Iowa State University Capstones, Theses and Graduate Theses and Dissertations Dissertations
2019 Controlling the deterioration of harvested grain/ seed to improve food security Bernard Darfour Iowa State University
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Controlling the deterioration of harvested grain/seed to improve food security
by
Bernard Darfour
A dissertation submitted to the graduate faculty
in partial fulfillment of the requirements for the degree of
DOCTOR OF PHILOSOPHY
Major: Industrial and Agricultural Technology
Program of Study Committee: Kurt A. Rosentrater, Major Professor Susana A. Goggi Carl J. Bern Thomas J. Brumm Joe P. Colletti
The student author, whose presentation of the scholarship herein was approved by the program of study committee, is solely responsible for the content of this dissertation. The Graduate College will ensure this dissertation is globally accessible and will not permit alterations after a degree is conferred.
Iowa State University
Ames, Iowa
2019
Copyright © Bernard Darfour, 2019. All rights reserved. ii
DEDICATION
I wholeheartedly dedicate this dissertation first to God Almighty. “With man this is impossible, but with God all things are possible.” Second, to my dear wife Janet
Ampofoa, and our lovely children Nana Yaa Osafo Darfour, Kwaku Acheampong Darfour, and Obeng Aseda Kwabena Darfour.
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TABLE OF CONTENTS
Page
TABLE OF CONTENTS ...... iii
LIST OF FIGURES ...... viii
LIST OF TABLES ...... xii
NOMENCLATURE ...... xiv
ACKNOWLEDGMENTS ...... xvii
ABSTRACT ...... xix
CHAPTER 1. GENERAL INTRODUCTION AND LITERATURE REVIEW ...... 1 1.1. Agriculture and Food Security in Ghana ...... 1 1.1.1. Food and Agriculture in Ghana ...... 1 1.1.2. Agricultural Sector Constraints ...... 2 1.1.4. Food Security Situation in Ghana ...... 7 1.1.5. Strategic Plans to Reduce Food Insecurity in Ghana ...... 8 1.1.6. Ghana’s Food Security Achievements ...... 9 1.2. Grain Cultivation and its Associated Problems: Overview of Ghana ...... 10 1.2.1. Grains Cultivated in Ghana ...... 10 1.2.2. Grain Losses in Ghana ...... 15 1.3. Maize in Ghana: An Overview of Cultivation to Processing ...... 17 1.3.1. Areas of Cultivation ...... 17 1.3.2. Consumption and Cost of Maize ...... 18 1.3.3. Post-Harvest Handling and Losses ...... 19 1.3.4. Post-Harvest Storage Methods ...... 20 1.3.5. Shelling and Cleaning of Grains ...... 25 1.3.6. Transport of Grains ...... 25 1.3.7. Grain Processing...... 26 1.4. Deterioration of Stored Seed: A Review ...... 27 1.4.1. Seed Quality, Vigor, and Viability ...... 27 1.4.2. Abiotic Factors Resulting in Seed Deterioration ...... 27 1.4.3. Biotic Factors ...... 28 1.4.4. Lipid Peroxidation (Biochemical) Deterioration of Stored Seeds...... 29 1.4.5. Resulting Effects of Seed Deterioration ...... 30 1.5. The Use of Synthetic and Botanical Insecticides in the Treatment of Maize Grains in Ghana: A Review ...... 31 1.5.1. Reasons for Maize Treatment after Harvesting ...... 31 1.5.2. The Various Techniques Used in Treating Maize Grains during Storage ... 32 1.5.3. Industrial Production of Chemicals Insecticides and Related Health and Environmental Issues ...... 33 1.5.4 Industrial Production of Natural (Essential Oils) Insecticides and
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Related Health and Environmental Issues ...... 35 1.5.5. Industrial Preparation of Powdered Botanical...... 37 1.5.6. Comparing Hazards and Challenges of Using Synthetic and Botanical Treatments ...... 38 1.5.7. Life Cycle Assessment (LCA) and Techno-Economic Analysis (TEA) of Crop Agriculture and Grain Treatment ...... 39 1.6. Deterioration of Stored Grain: A Review ...... 42 1.6.1. Factors that Affect Grain Storage ...... 42 1.6.2. Grain Respiration and Loss in Dry Matter ...... 43 1.6.3. Activities of Molds or Fungi, Insects, and Pests in Grain Deterioration...... 43 1.7. References ...... 44 Figures ...... 63 Table ...... 72
CHAPTER 2. RESEARCH PROBLEM, JUSTIFICATION, OBJECTIVES, AND HYPOTHESES ...... 73 2.1. Research Problem ...... 73 2.2. Research Justification ...... 73 2.3. Research Objectives ...... 75 2.4. Research Hypotheses ...... 76 2.5. Dissertation Outline ...... 78 2.6. References ...... 79
CHAPTER 3. STORABILITY OF ORGANIC AND CONVENTIONAL SORGHUM GRAINS AT CONSTANT RELATIVE HUMIDITY, AND VARIED TEMPERATURES ...... 83 Abstract ...... 83 3.1. Introduction ...... 84 3.2. Materials and Methods ...... 86 3.2.1. Experimental design ...... 86 3.2.2. Moisture content (MC) of grain ...... 86 3.2.3. Hermetic storage studies ...... 86 3.2.4. Non-hermetic storage studies ...... 87 3.2.5. Data collection and analysis ...... 87 3.3. Results and Discussion ...... 87 3.3.1. MC of grains in hermetic jars ...... 87 3.3.2. MC of grains in non-hermetic jars ...... 89 3.3.3. Percent mortality of S. zeamais ...... 90 3.3.4. Percentage loss in grain weight in non-hermetic jars ...... 91 3.3.5. The emergence of new S. zeamais in non-hermetic jars ...... 92 3.3.6. Depletion of oxygen (O2), the increase in carbon dioxide (CO2), and S. zeamais mortality in hermetic jars...... 93 3.4. Conclusions ...... 95 3.5. References ...... 96 Tables ...... 101 Figures ...... 105
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CHAPTER 4. ENVIRONMENTAL ASSESSMENT AND COST ANALYSIS OF THE MANUFACTURING, TRANSPORT, AND USE OF ACTELLIC SUPER AND NEEMAZAL INSECTICIDES FOR THE TREATMENT OF MAIZE GRAINS ...... 112 Abstract ...... 112 4.1. Introduction ...... 113 4.2. Materials and Methods ...... 115 4.2.1. Environmental assessment ...... 115 4.2.2. Cost Analysis ...... 117 4.3. Results and Discussion ...... 118 4.3.1. Global warming potential (CO2 equivalent emissions and impacts) ...... 118 4.3.2. Ecotoxicity and human health impacts ...... 119 4.3.3. Cost analysis ...... 122 4.4. Conclusions ...... 124 4.5. References ...... 126 Figures ...... 130
CHAPTER 5. PRE-HARVEST AND POST-HARVEST FARMER EXPERIENCES AND PRACTICES IN FIVE MAIZE GROWING REGIONS IN GHANA ...... 138 Abstract ...... 138 5.1. Introduction ...... 139 5.2. Materials and Methods ...... 139 5.2.1. The study area and administering of interviews in Ghana ...... 139 5.2.2. Data presentation ...... 140 5.3. Results and Discussion ...... 140 5.3.1. Demographic information on farmers ...... 140 5.3.2. Cultivated farm size, and grain handling before, during and after harvest ...... 141 5.3.3. Post-harvest grain drying, sorting, and storage ...... 143 5.3.4. Post-harvest grain treatment, and use of damaged ears...... 144 5.3.5. Molds infestation, knowledge of farmers, and AEAs’ activities ...... 145 5.3.6. Kinds of PHL and pest infestations ...... 146 5.4. Conclusions ...... 147 5.5. References ...... 148 Tables ...... 151 Figures ...... 158 Appendix 5.1. Questionnaire for Preharvest and Postharvest Maize Grain Losses, Harvest and Storage Practices, and Farmers' Knowledge of Mycotoxins...... 165
CHAPTER 6. INVESTIGATING THE PERIODIC PHYSICAL DISTURBANCE METHOD IN GHANA TO CONTROL ADULT SITOPHILUS ZEAMAIS ...... 167 Abstract ...... 167 6.1. Introduction ...... 168 6.2. Materials and Methods ...... 170 6.2.1. Research site and experimental design ...... 170 6.2.2. Data analysis...... 171 6.3. Results ...... 171
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6.4. Discussion ...... 172 6.5. Conclusions ...... 175 6.6. References ...... 175 Tables ...... 178
CHAPTER 7. ASSESSING THE EFFICACY OF HERMETIC STORAGE BAGS AGAINST WOVEN POLYPROPYLENE BAGS BY FARMERS IN GHANA ...... 181 Abstract ...... 181 7.1. Introduction ...... 182 7.2. Materials and Methods ...... 184 7.2.1. Experimental set-up ...... 184 7.2.2. Data analysis...... 185 7.3. Results ...... 186 7.4. Discussion ...... 187 7.4.1. Percent Number of Damaged Bags ...... 187 7.4.2. Percentage of damaged grain ...... 188 7.4.3. Mass of powder (fines) and grain weight loss ...... 189 7.4.4. Percent S. zeamais mortality ...... 190 7.4.5. Statistical comparison of woven polypropylene and GrainPro bags ...... 191 7.5. Conclusions ...... 192 7.6. References ...... 193 Figures ...... 197 Tables ...... 203
CHAPTER 8. EFFECTIVE CONTROL OF MOISTURE CONTENT OF STORED SEEDS IN HERMETIC STORAGE USING ZEOLITE BEADS ...... 205 Abstract ...... 205 8.1. Introduction ...... 206 8.2. Materials and Methods ...... 209 8.2.1. Reactivation of zeolite beads, and determination of zeolite beads capacity ...... 209 8.2.2. Determination of seeds moisture content (MC) ...... 210 8.2.3. Estimating the appropriate quantity of zeolite beads necessary for safe seed storage ...... 210 8.2.4. Experimental design ...... 210 8.2.5. Determination of seed germinability, viability, and vigor after storage .... 211 8.2.6. Data analysis...... 211 8.3. Results and Discussion ...... 212 8.3.1. The effectiveness of the zeolite beads in seed drying ...... 212 8.3.2. Precision and accuracy of zeolite beads in estimating the final MC of seeds ...... 213 8.3.3. Effects of zeolite beads on seed germination at 4 and 7 days ...... 214 8.3.4. Effect of zeolite beads on SGR ...... 217 8.4. Conclusions ...... 219 8.5. References ...... 220 Tables ...... 223 Figures ...... 226
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CHAPTER 9. COST ASSESSMENT OF FIVE DIFFERENT MAIZE GRAIN HANDLING TECHNIQUES ...... 228 Abstract ...... 228 9.1. Introduction ...... 229 9.2. Materials and Methods ...... 230 9.2.1. Goal and scope ...... 231 9.2.2. System boundary ...... 231 9.2.3. Functional unit (FU) ...... 231 9.2.4. Assumptions ...... 231 9.2.5. Experimental design ...... 232 9.3. Results and Discussion ...... 232 9.3.1. The annual capital and operational costs, and profits ...... 232 9.3.2. The annual capital and operational costs, and profits at percentage grain losses ...... 235 9.3.3. Economies of scale of capital and operational costs ...... 239 9.3.4. Breakeven points (in units)...... 240 9.4. Conclusions ...... 241 9.5. References ...... 243 Tables ...... 247 Figures ...... 251
CHAPTER 10. GENERAL CONCLUSIONS, RECOMMENDATIONS, AND FUTURE RESEARCH WORK ...... 264 10.1. General Conclusions ...... 264 10.2. Recommendations ...... 267 10.3. Future Work ...... 267
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LIST OF FIGURES
Page
Figure 1.1 Percentage of the Various Sectors of Agriculture Production in Ghana ..... 63
Figure 1.2 The Major Five Grains Cultivated in Ghana ...... 63
Figure 1.3 The Agro-ecological Zones in Ghana (FAO 2005, Modified), RESPA 2008) ...... 64
Figure 1.4 Different Platforms for Maize Drying in Africa (Hodges, 2001)...... 65
Figure 1.5 On-Ground Drying of Maize Grains in Africa (World Bank, 2011)...... 65
Figure 1.6 Mud Silos for Maize Storage in Nigeria (GKI, 2014 credited to IITA) ...... 66
Figure 1.7 Different Kinds of Metal Silos for Maize Storage (CGIAR, 2013) ...... 66
Figure 1.8 Purdue Improved Crop Storage (PICS) Bags for Grain Storage (FoodTrade, 2017)...... 67
Figure 1.9 PIDS Technology (Ileleji, 2012, PIDS-I Prototype) for Drying Grains...... 67
Figure 1.10 Shucking and Shelling Corn in Rural Ghana (MIT, 2015)...... 68
Figure 1.11 Different Types of Local Maize Shellers Used in Ghana (MIT, 2015) ...... 68
Figure 1.12 Unit Operations of Chemical Synthesis (Insecticides), and Energy and Mass Flows (In & Out)...... 69
Figure 1.13 Flow Chart for Essential Oil Production, and Material and Energy Flow ... 70
Figure 1.14 US Green House Emission in 2014 (EPA, 2016) ...... 71
Figure 3.1 The Conventional (a) and Organic (b) Grains Showing Extent of Damage Caused by S. zeamais After 30 Days of Storage ...... 105
Figure 3.2 Oxygen Concentration Measured at 15oC for 15 Days...... 106
Figure 3.3 Oxygen Concentration Measured at 20oC for 15 Days ...... 107
Figure 3.4 Oxygen Concentration Measured at 30oC for 15 Days...... 108
Figure 3.5 Carbon Dioxide Concentration Measured at 15oC for 15 days...... 109
Figure 3.6 Carbon Dioxide Concentration Measured at 20oC for 15 Days...... 110
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Figure 3.7 Carbon Dioxide Concentration Measured at 30oC for 15 Days...... 111
Figure 4.1 System Boundary for the Environmental Assessment: Sustainable Minds was used for the Manufacturing and Transport of Insecticides and TRACI was Used for Insecticides Usage ...... 130
Figure 4.2 CO2 Equivalent Emissions and Impacts of Pirimiphos-Methyl and Permethrin during Manufacturing and Transport (Air and Sea Freights) per kg of insecticide. Impact per FU (mPts) = ecological, resource depletion and human health damage...... 131
Figure 4.3 Ecotoxicity Impacts of Azadirachtin, Pirimiphos-Methyl, and Permethrin usage to Air, Water, and Soil per 1 Kg of Maize grain...... 132
Figure 4.4 Human Health Impacts of Azadirachtin, Pirimiphos-Methyl, and Permethrin usage to Air, Water, and Soil per 1 Kg of Maize grain...... 133
Figure 4.5 The Costs of Azadirachtin and Actellic Super Per Treatment of 1 kg of Maize at Present Price, and Dollar-to-Cedi Exchange Rate and an Inflation rate of -50%, 50%, and 100% ...... 134
Figure 4.6 Costs of Treating 1 Kg, 500 Kg, 1000 Kg, 1500 Kg, 2000 Kg, and 2500 Kg Capacities of Maize Grains by Using Azadirachtin & Actellic Super . 135
Figure 4.7 Change in the Costs of Treatment by Using Azadirachtin and Actellic Super at Different Capacities of Grains...... 136
Figure 4.8 The Unit Cost of Treating Maize Grain in Ghana (Economies of Scale). . 137
Figure 5.1 Improvised Corn Shelling Device, and a Plastic Gallon for the Hermetic Storage of Maize Grain in Ghana...... 158
Figure 5.2 Locally Made Shelling Machine Used by Some Farmers to Shell Maize in the Northern Region of Ghana ...... 158
Figure 5.3 Shelled Grain Being Dried on the Bare Floor in Brong Ahafo Region, Ghana...... 159
Figure 5.4 Traditional Granary for Maize Storage Used by Some Farmers in Ghana...... 160
Figure 5.5 Basil Herb Plant Used for Treating Maize Grain by Some Farmers in Ghana ...... 161
Figure 5.6 The Percent of Maize Farmers that Observed Post-Harvest Losses in Maize Grain...... 162
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Figure 5.7 Different Kinds of Post-Harvest Losses Observed by Maize Farmers in Ghana...... 163
Figure 5.8 The Losses (%) in Maize Grain Due to the Different Kinds of Pest Infestations in Ghana...... 164
Figure 7.1 Percent of Woven Polypropylene and GrainPro Bags Damaged by S. zeamais During the 6 Months of Grain Storage in Ghana...... 197
Figure 7.2 Percent of Maize Grain Damaged by S. zeamais in Both Bags During the 6 Months of Grain Storage in Ghana ...... 198
Figure 7.3 Weight (g/1 kg) of Powder Produced as a Result of Grain Damaged by S. zeamais During the 6 Months of Grain Storage in Ghana ...... 199
Figure 7.4 Percent Mortality of S. zeamais in Both Storage Bags During the 6 Months of Grain Storage in Ghana ...... 200
Figure 7.5 Maize Grain in Intact (a) and Mice-Damaged (b) GrainPro Bags; and Maize Grain in Damaged Woven Polypropylene Bags (c) During the 6 Months of Grain Storage in Ghana...... 201
Figure 7.6 Quality of Maize Kernels Stored in Woven Polypropylene Bags (a) and GrainPro Bags (b) During the 6 Months of Grain Storage in Ghana ...... 201
Figure 7.7 Powder (flour) Produced in Woven Polypropylene Bags Due to S. zeamais (a), and Kernel Spillage Due to Mice Attack on GrainPro Bags (b) During the 6 Months of Grain Storage in Ghana ...... 202
Figure 8.1 Percent Germination at 4 Days of All Seeds with Initial MC (%) Stored With or Without Zeolite Beads, and Stored for 1, 3, and 6 Months in Warm and Cold Temperatures...... 226
Figure 8.2 Percent Germination at 7 Days of All Seeds with Initial MC (%) Stored With or Without Zeolite Beads, and Stored for 1, 3, and 6 Months in Warm and Cold Temperatures...... 227
Figure 9.1 System Boundary for the Cost Analysis of the Various Handling Methods ...... 251
Figure 9.2 The Annual Capital and Operational Costs (US Dollars), Total Annual Benefits and Profits (US Dollars) Made on Each Handling/Storage Method at 2.8 Mg/year Handling Capacity at 0%, 30%, 50%, and 70% Grain Price Increase...... 252
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Figure 9.3 The Annual Capital and Operational Costs (US Dollars), Total Annual Benefits and Profits (US Dollars) Made on Each Handling/Storage Method at 14 Mg/year Handling Capacity at 0%, 30%, 50%, and 70% grain Price Increase...... 253
Figure 9.4 The Annual Capital and Operational Costs (US Dollars), Total Annual Benefits and Profits (US Dollars) Made an Each Handling/Storage Method at 28 Mg/year Handling Capacity at 0%, 30%, 50%, and 70% Grain Price Increase...... 254
Figure 9.5 The Annual Capital and Operational Costs (US Dollars), Total Annual Benefits and Profits (US Dollars) Made an Each Handling/Storage Method at 2.8 Mg/year Handling Capacity at 0% to 7%, and 0% to 30% Grain Quantity Losses...... 255
Figure 9.6 The Annual Capital and Operational Costs (US Dollars), Total Annual Benefits and Profits (US Dollars) Made an Each Handling/Storage Method at 14 Mg/year Handling Capacity at 0% to 7%, and 0% to 30% Grain Quantity Losses ...... 256
Figure 9.7 The Annual Capital and Operational Costs (US Dollars), Total Annual Benefits And Profits (US Dollars) Made an Each Handling/Storage Method at 28 Mg/year Handling Capacity at 0% to 7%, and 0% to 30% Grain Quantity Losses ...... 257
Figure 9.8 Economies of Scale of Capital and Operational Costs ($/Mg/y) of Using Metal Silo and All Accessories...... 258
Figure 9.9 Economies of Scale of Capital and Operational Costs ($/Mg/y) of Using Metal Silo Only ...... 259
Figure 9.10 Economies of Scale of Capital and Operational Costs ($/Mg/y) of Using PICS Bags Only ...... 260
Figure 9.11 Economies of Scale of Capital and Operational Costs ($/Mg/y) of Using Woven Polypropylene Bags and Phosphine Tablets...... 261
Figure 9.12 Economies of Scale of Capital and Operational Costs ($/Mg/y) of Using Woven Polypropylene Bags Only...... 262
Figure 9.13 Breakeven Point Units (The Quantity of a Particular Handling Capacity Needed to Breakeven) of Each Handling Method Per Handling Capacity (Year) ...... 263
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LIST OF TABLES
Page
Table 1.1 Estimated Ghana’s Maize Market Composition (Gage et al., 2012) ...... 72
Table 3.1 Moisture Content of the Conventional and Organic Grains at 15oC ...... 101
Table 3.2 Moisture Content of the Conventional and Organic Grains at 20oC ...... 102
Table 3.3 Moisture Content of the Conventional and Organic Grains at 30oC ...... 103
Table 3.4 Percent Mortality of S. zeamais, and Loss of Grain Weight in the Conventional and Organic Grains in the Hermetic & Non-Hermetic Jars . 104
Table 3.5 Correlation Between the Moisture Content of Grains, Mortality of S. zeamais, and Loss in Grain Weight...... 104
Table 5.1 Regions and Districts in Which the Interviews Were Administered on Maize Farmers in Ghana ...... 151
Table 5.2 Demographic Data on Maize Farmers in Ghana...... 152
Table 5.3 Sizes of Farms Cultivated by Maize Farmers, and Different Means of Harvesting Grain in Ghana...... 152
Table 5.4 Pre-Harvest Losses and Associated Agents Experienced by Maize Farmers in Ghana ...... 153
Table 5.5 Harvesting of Grains, Threshing, and Number of Months of Storing Maize Grain by Farmers in Ghana...... 154
Table 5.6 Post-Harvest Practices Used by Maize Farmers, and Weevil Infestations in Ghana ...... 155
Table 5.7 Treatment of Shelled Maize Grain, and Handling of Damaged Ears by Maize Farmers in Ghana ...... 156
Table 5.8 The Use of Harvested Maize Grain, Knowledge of Maize Farmers on Mycotoxins, and Activities of AEAs in Ghana...... 157
Table 6.1 The Number of S. zeamais Dead and Alive, and the Percent Mortality at 30, 60 and 90 Days of Grain Storage...... 178
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Table 6.2 Comparing the Percent Mortality of S. zeamais between the Disturbed and Undisturbed Samples at 30, 60 and 90 Days of Grain Storage...... 179
Table 6.3 Comparing the Percent Mortality of S. zeamais in the Disturbed or Undisturbed Samples at 30, 60 and 90 Days of Grain Storage ...... 179
Table 6.4 Comparing the Percent Mortality of S. zeamais in the Disturbed Samples per Each Farmer at 30, 60 and 90 Days of Grain Storage...... 180
Table 7.1 The Average Number of Live and Dead S. zeamais per 1 kg of Grain, and Percent Mortality During the 6 Months of Grain Storage in Ghana. ... 203
Table 7.2 ANOVA Showing Significant Differences between the Use of GrainPro and Woven Polypropylene Bags among the Seven Farmers During the 6 Months of Grain Storage in Ghana ...... 204
Table 8.1 The Initial MC of Seeds, and Storage Condition and Months Used in Seeds Storage. Final MC of Seeds Stored With or Without Zeolite Beads After 1, 3 and 6 Months of Storage ...... 223
Table 8.2 Mean MC and Standard Deviation from the Mean (S.D.) between the Expected and the Final MC for Maize Seed Stored for 1, 3 and 6 Months in Jars With or Without Zeolite Beads in Warm and Cold Temperatures .. 224
Table 8.3 The Number of Normal Seedlings and Seedling Growth Rate (SGR in mg/seedling) of All Seeds with Initial MC (%) Stored with or without Zeolite Beads, and Stored for 1, 3, and 6 Months in Warm and Cold Temperatures...... 225
Table 9.1 The Specifications and Prices of Equipment and Materials Used in the Cost-Analysis ...... 247
Table 9.2 Assumptions on Utility and Services Costs, and Some Parameters Used in the Cost-Analysis ...... 248
Table 9.3 Equations Used in the Cost-Analysis Calculations...... 249
Table 9.4 Experimental Design and Parameters Used in the Cost-Analysis ...... 250
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NOMENCLATURE
AEAs Agricultural Extension Agents
AOSA Association of Official Seed Analysts
APHLIS African Postharvest Losses Information System
ASAE American Society of Agricultural Engineers
CFD Computational Fluid Dynamics
CGIAR Consultative Group on International Agricultural Research
CIMMYT International Maize and Wheat Improvement Center
EMC Equilibrium Moisture Content
FAO Food and Agriculture Organization
FASDEP Food and Agriculture Sector Development Policy
FAOSTAT Food and Agricultural Organization of the United Nations-Statistics division
FAPDA Food and Agriculture Policy Decision Analysis
FFG Feed the Future Ghana
GHG Green House Gases
GIZ Deutsche Gesellschaft für Internationale Zusammenarbeit
HSD Honestly Significant Difference
IBD International Business Daily
ICRISAT International Crops Research Institute for the Semi-Arid Tropics
IFAD International Fund for Agricultural Development
IFBC International Food Biotechnology Council
IFPRI International Food Policy Research Institute
IPCC Intergovernmental Panel on Climate Change
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IPM Integrated Pest Management
IRRI International Rice Research Institute
ISSER Institute of Statistical, Social and Economic Research
ISO International Standard Organization
ISTA International Seed Testing Association
Kwh Kilowatt-hour
LCA Life Cycle Assessment
MC Moisture Contents
MDG Millennium Development Goal
MoFA Ministry of Food and Agriculture-Ghana.
NAFCO National Food Buffer Stock Company
NOx Nitrous oxide
N2O Nitrogen dioxide
NPAS Northern Presbyterian Agricultural Services
PAN Pestizid Aktions-Netzwerk
PBB Pilot Program Based Budget
PG Percent Germination
PHL Postharvest Loss
PICS Purdue Improved Crop Storage
PIDS Purdue Improved Drying Stove
PSC Postharvest Service Centers
PSE Penn State Extension
RESPA Re-use of Ecological Sanitation Products
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R.H Relative Humidity
SARI Savanna Agricultural Research Institute
SDC Swiss Agency for Development and Cooperation
SGR Seedling Growth Rate
SRID Statistics Research Information Directorate
SSA Sub-Saharan Africa
TRACI Tool for the Reduction and Assessment of Chemical and other Environmental Impacts
USAID United States Agency for International Development
USDA United States Department of Agriculture
EPA Environmental Protection Agency, United States of America
WFP World Food Program
WHO World Health Organization
WMO World Meteorological Organization
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ACKNOWLEDGMENTS
I would like to sincerely thank my principal advisor Dr. Kurt A. Rosentrater for his in-depth support by way of his exceptional guidance, advice, patience, and encouragement throughout my study in ISU. By the form of his mentorship, I have improved in many facets of life including but not limited to hard work, teamwork, and dedication to work.
His incredible experience has rejuvenated me in many endeavors which would be beneficial to myself, and society. I would equally like to express my heartfelt gratitude to my committee members Dr. Susana A. Goggi, Dr. Carl J. Bern, Dr. Thomas J. Brumm, and
Dr. Joe P. Colletti for their indispensable contributions towards my success in this Ph.D. program. Their valuable advice, discussions, prompt feedbacks among other things immensely helped me to come this far.
I would also like to thank the United States Agency for International Development-
Ghana (USAID-Ghana), under the Feed the Future programme through the auspices of the
Agricultural Technology Transfer-Ghana (ATT-Ghana) programme. Without their financial support, I wouldn’t have made such progress in my Ph.D. education at this crucial stage of my career. I would like to also thank the management of the Ghana Atomic Energy
Commission (GAEC), and the Biotechnology and Nuclear Agriculture Research Institute
(BNARI) for the permission granted me to pursue my Ph.D. education. I would gracefully also like to appreciate the dedication, friendship, and the enormous help received from
Denise Bjelland, Eduarda Becerra, and Tamara Martin from the Office of Global Programs in the College of Agriculture, ISU. I even lack words to express how thankful I am to them.
Also, I would like to thank all my friends, my colleagues, department faculty and staff at Iowa State University. I must confess, I am immensely indebted to each individual
xviii who made my study in ISU successful and enjoying. It is such an unforgettable experience working with you all.
Last but not least, I would like to thank my parents, siblings, wife, children, and my spiritual father Rev. Thomas Asiedu and family. Their prayers, frequent calls to inquire about my health and success, and their love and encouragement had been beneficial. My deepest wish and prayer is “And my God will meet all your needs according to the riches of his glory in Christ Jesus.” Thank you for faithfully assuming the mantle in my absence.
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ABSTRACT
The agriculture sector is the largest source of employment for Ghanaians and it is dominated by smallholder farmers. The challenges in the agriculture sector are many which include food insecurity. Maize offers a significant source of calories, and accounts for 50% of the total cereal production in Ghana, with the reported postharvest loss (PHL) between
5% and 70%. Improving food security through a reduction of PHL is imperative for meeting current development objectives. Sitophilus zeamais can inflict serious damage to maize in storage leading to about 20% to 50% or more losses within 3 to 6 months. The lack of industrial processing of maize and improper storage facilities have compelled farmers to sell their bumper harvest at low prices, and stored grains get rotten. Grain or seed deterioration caused by insects, diseases, rodents, physiological or chemical changes, and pathogenic microorganisms can be minimized by applying appropriate storage and treatment techniques. About 80% to 90% of Ghanaian farmers use pesticides, and about
20% of pesticides used across the world could be found in developing nations, and this poses environmental and health dangers. Complete dependence on pesticides is unsustainable, and the environmental and health implications are unavoidable. Synthetic chemicals although effective against S. zeamais, they are misused or misapplied exposing farmers and consumers, and the environment to unforeseen risks. The overall objective of this research was to use non-chemical techniques to control the deterioration of stored grain/seed to minimize food insecurity, and to improve the financial security of farmers.
Small-sized grains like sorghum are important for food security. Hence, the storability of organic and conventional sorghum grains at constant RH and different temperatures was studied. Susceptibility of the two grain types to S. zeamais, grain
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moisture, and rate of changes in O2 and CO2 concentrations in hermetic jars were similarly considered. Organic and conventional sorghum grains were stored in an environmental
o o o chamber at 15 C, 20 C and 30 C, and 75% RH for 0, 15 and 30 days. The daily CO2 and
O2 concentrations measured in the hermetic jars showed an increase in CO2 and a decrease in O2 as the temperature increased. The changes in CO2 and O2 concentrations in the hermetic jars might have resulted in the 100% S. zeamais Mortality. The quality and quantity of sorghum grain stored in hermetic jars were maintained, especially at low temperatures.
Further, the environmental impacts assessment and cost analysis of the active ingredients in actellic super (pirimiphos-methyl and permethrin) and NeemAzal
(Azadirachtin) for maize grain treatment were evaluated. A functional unit of 1 kg of grain or insecticide was used in the analysis. Pirimiphos-methyl manufacturing had the lowest
CO2 eq.kg/kg emissions and impacts (mPts/kg), and permethrin manufacturing had worse
CO2 eq.kg/kg emissions and impacts. The CO2 eq.kg/kg emissions and impacts were severe when pirimiphos-methyl and permethrin were air shipped, hence sea transport is encouraged. Pirimiphos-methyl usage had the highest ecotoxicity impacts, and permethrin had the least. Azadirachtin had no human health impacts, however, pirimiphos-methyl exhibited human health impacts while permethrin was negligible. The price of the
NeemAzal was 224% high compared to actellic super as NeemAzal is applied in a larger quantity.
A semi-structured questionnaire was used to collect data on the different kinds of pre-harvest and post-harvest losses that maize farmers in Ghana encounter, storage practices, and farmers’ awareness and knowledge of mycotoxin contamination. The male
xxi maize farmers were many compared to females, and at least 70% of farmers were over 40 years of age. Over 50% of farmers except the Northern region completed at least basic education. At least 90% of farmers experienced at most 2% pre-harvest losses. Farmers observed PHL of between 60% and 100%. Typically, grains were stored in polypropylene bags for 3 to 12 months. Farmers used synthetic insecticides, and pepper or basil or neem plant materials to control maize weevils during grain storage. The Northern region had the highest usage of plant material for grain treatment, and the least maize weevil infestations.
In addition, the efficacy of the periodic physical disturbance method on S. zeamais mortality, and the adoptability of the method by subsistence farmers in Ghana was studied.
The maize grains were non-hermetically stored in plastic buckets for 30, 60 and 90 days at
27±5oC. The buckets were physically disturbed for about 2.5 minutes twice a day. The physical disturbance did not cause any significant S. zeamais mortality. The failure of the method could be due to human error or the large number of S. zeamais used inundated the technique or the high temperature, RH and grain MC favored the growth and development of S. zeamais. Importantly, despite the failure of the method in causing S. zeamais mortality, the quality of grain in the disturbed buckets was maintained.
The study also considered the evaluation of the advantages of GrainPro bags over woven polypropylene bags during maize grain storage. All the woven polypropylene bags but no GrainPro bags were damaged by S. zeamais. The percentage of damaged grain in woven polypropylene bags was between 91.9% and 94.4%, and from 0.2% to 0.7% in
GrainPro bags. Hundred percent S. zeamais mortality was achieved in the GrainPro bags compared to less than 10.0% in the woven polypropylene bags. Grains were better stored in GrainPro bags compared to woven polypropylene bags.
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Similarly, the study also focused on seed storage using zeolite beads. Maize seeds of the same variety at 15.3%, 11.3%, and 9.8% moisture were stored in airtight glass jars for 1, 3 and 6 months. Seeds at 15.3% MC stored without zeolite beads had increased moisture, and decreased germination and vigor. Seeds at 11.3% and 9.8% MC stored with or without zeolite beads had moisture maintained or decreased, however, germination and vigor increased. Germination linearly increased from 91.0% to 99.0% during the 1 to 6 storage months. The SGR at 6 months was generally high. Maize seeds with high initial
MC can be stored safely, and lose moisture during storage when using zeolite beads.
Zeolite beads did not negatively affect seed germination and vigor, and therefore an alternative to seed refrigeration.
Further, the cost-effectiveness of five different maize grain handling techniques was studied with computer simulation. The annual capital and operational costs of using m. silo + acc. or m. silo were so high, and the expenditure could only be afforded through farmers-cooperatives. But the capital and operational costs of using either PICS or w. PP.
+ Phos. or w. PP. were comparatively so low, and most individual farmers could afford.
The annual capital and operational costs decreased with the increased scale of production.
Using PICS or w. PP. or w. PP. + Phos., the breakeven was reached even at the low production scale of 2.8 Mg. Nonetheless, the high percentage of grain losses mostly related to using w. PP., and w. PP. + Phos. should not be disregarded. Handling grain mechanically with m. silo + acc. or m. silo through a farmers-cooperative could improve food security and financial prospects of farmers. Individually, PICS bags or other hermetic bags rather than w. PP. or w. PP. + Phos. could be used to improve food security and income security.
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CHAPTER 1. GENERAL INTRODUCTION AND LITERATURE REVIEW
1.1. Agriculture and Food Security in Ghana
1.1.1. Food and Agriculture in Ghana
MoFA (2007) reported that agriculture is dominantly practiced on smallholder level using simple technology in producing about 80% of the total agricultural output in Ghana.
According to the report, about 2.74 million households own a farm or are keeping livestock.
In reference to the 2000 census, 50.6% (4.2 million people) of the labor force, were directly involved in agriculture. From the census, about 90% of most farmlands were not up to two hectares in size, and mostly oil palm, rubber, coconut, maize, rice and pineapples farms are vast. Generally, agriculture in Ghana is rainfall dependent, although in 1999 an estimated
6,000 farm enterprises across Ghana used some means of irrigation. Reports indicate that the average farmland irrigated in 2002 was around 11,000 ha with an estimated potential area for irrigation of 500,000 ha. Generally, 51% of Ghana’s cereal needs are locally produced, 60% of fish requirements are locally produced, 50% of meat is locally produced, and less than 30% of agro-based industries’ raw materials are locally produced (fig. 1.1).
The agriculture sector controls the economy of Ghana, accounting for 23% of the national
Gross Domestic Product (GDP) in 2012 (FAO and FAPDA, 2015). Agriculture is still the largest share contributor to the GDP. Since 2000, there has been a total of between 35.8% and 37% contribution to the GDP from agriculture. Agricultural growth increased from around 4% in 2000 to 6% in 2005, with the greatest growth contribution from the cocoa industry. According to the report by FFG (2014), there has been consistency in growth and poverty reduction over the past two decades making Ghana a successful African country.
The annual GDP has grown between 4% and 8% over the past decade, and this yearly
2 growth is perceived to exist for years to come. Poverty reduction, especially in southern
Ghana has been driven by agricultural growth, and agriculture sector employs the largest number of people, and these people are predominantly smallholder farmers that produce food and cash crops. Over the past 10 years, Ghana’s overall poverty reduction rate has been from 52% to 28%. Despite Ghana’s progress in agriculture, Ghana still imports about
70% and 15% respectively of rice and maize consumed. The rise in incomes and increasing urban growth rate is expected to increase the demand for both crops.
1.1.2. Agricultural Sector Constraints
There are aggregated factors hindering agricultural growth, and these factors are discouraging farmers from investing and producing. Some of these factors are limited access to changes in technology and the existence of poor infrastructure. Diversity in
Ghana’s agroecology has compounded these challenges. Ghana’s Ministry of Food and
Agriculture in 2007 listed some constraints in the agriculture sector.
1.1.2.1. Human resource and managerial skills
The agricultural sector having over 60% of the population including farmers, traders and processors constitute the largest sector. Agriculture is also a critical sector for women; about half (48.7%) of the total female population is self-employed in agriculture, with the majority being engaged in food production. Although the current population of farmers is aging, the youth are not willing to engage in agriculture. The literates are not much engaged in agriculture, and therefore dissemination of information, novel methods, regulations, and policies are paramount (MoFA, 2007).
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1.1.2.2. Natural resource management
Agriculture in Ghana is based on natural resources, comprising of production of crops and livestock, wildlife hunting, rain-dependent agriculture, and fish from natural water bodies. Sustainability of natural resources is threatened by some practices such as the burning of the bush, and improper use of modern technologies such as irrigation and agrochemicals. It is reported that 69% of Ghana‘s total land surface at a cost of 2% of GDP is considered prone to severe erosion (MoFA, 2007).
1.1.2.3. Technology development and dissemination
Low productivity in agriculture can be due to poor conditions of soils, irregular pattern of rainfall, disease and pest outbreaks, lack of access to good varieties of planting materials and seeds. Lack of access to good market incentives and relevant inputs, limited access to processing technologies, transports, handling and storing of commodities of the crop, fish, and livestock are challenging factors. There is also limited knowledge in post- harvest management, most especially of perishable produce, resulting in high post-harvest losses of about 20% to 50% for fruits, vegetables, roots and tubers, and about 20% to 30% for cereals and legumes. The women have been using traditional processing technologies, which have low yields, strenuous, and not be of good product quality (MoFA, 2007).
1.1.2.4. Infrastructure
Movement of agricultural commodities is a challenge as road and transport infrastructures are inadequate and poor. This constraint particularly has retarded agriculture growth and development in some high potential areas. Most feeder roads connecting farms to villages are very poor compelling farmers to carry their produce on their heads from farms to markets. Poor road infrastructure also has a toil on the cost of important inputs such as fertilizer. Most markets have limited infrastructures such as suitable commodity
4 specific storage facilities, toilet facility, good and hygienic environment, accessibility by car or truck and limited space (MoFA, 2007).
1.1.2.5. Market access
There is also limited marketing skills, limited processing and product development for good utilization of raw materials and mostly weak commodity value chains. The increasing consciousness of food safety and phytosanitary in international trade require a growing challenge to market access, especially for high-value agricultural export commodities. The majority of local consumers and producers have a low consciousness about food safety, and this has caused farmers, processors and traders not to follow good practices in agriculture and manufacturing (MoFA, 2007).
1.1.2.6. Food insecurity
Ghana faces eminent food insecurity as the average yield has not been growing. In almost two decades the importation of commercial food and food aid have reached about
4.7% of food needs. Food production and availability per year are dependent on rainfall during and between growing seasons, and the level of production. This creates food insecurity at household levels, making community areas poor and chronically distressed.
Ghana is generally food secure, but there are pockets of food insecurity existing in all regions as a result of acute limited resources and limited alternative livelihood chances for most people to meet their dietary needs. Adverse weather conditions and bushfires have had a severe impact on smallholder farm enterprises (MoFA, 2007).
1.1.2.7. Irrigation development and management
Drylands less than 1% are using irrigation, and improper management of the present systems further limits their effectiveness. There are public irrigation systems that operate at approximately one-third of their designed capacity. This has caused low yield and low
5 cropping intensity because of lack of good operation and maintenance of irrigation facilities. Formal irrigation development is highly supply-driven, and its over-reliance has limited the areas under irrigation (MoFA, 2007).
1.1.3. Food Security Indicators
Food security was agreed to exist when: “All people, at all times, have physical and economic access to sufficient, safe and nutritious food to meet their dietary needs and food preferences for an active and healthy life” (FAO, 1996). Achieving food security requires that the aggregate availability of physical supplies of food is sufficient, that households have adequate access to those food supplies through their own production, through the market or other sources, and that the utilization of those food supplies is appropriate to meet the specific dietary needs of individuals. Food security is a complex phenomenon that exhibits itself in numerous physical conditions resulting from multiple causes. The World
Food Summit of 1996 established four dimensions of food security: availability, access, stability, and utilization.
1.1.3.1. Food availability
FAO (2014a) indicated that one of the key determining factors of food security depends on the availability of food and its constituents. There could be the availability of dietary energy but not diversified enough to provide the macro and micronutrients essential for a healthy life. Information on food available for consumption is mainly obtained at an aggregate level through food balance sheets, which give data on the quantity of energy and protein available on each day per person at the national level. Dietary energy supply could be a good indicator of food availability, but other indicators, such as food adequacy, are needed to provide information on the gap between food supply and average energy
6 requirements. Between 1990 and 2011, the level of energy supply obtained from cereals, roots, and tubers slightly dropped in West Africa.
1.1.3.2. Food accessibility
Hunger will continue to be an issue as long as the available food is not adequately distributed among the population. All people should have access to food physically and economically. Access to food is basically determined by incomes ability of households and individuals to access social support, and prices of food. Beyond economic affordability, physical access to food is enhanced by the availability of infrastructures, such as rail lines and tarred roads. As regards roads, from 2005 to 2010, Ghana among other seven other nations had the highest road density (14 to 110 km per 100 square km of land area).
Aggregate FAO projections show that, even with decreasing consumption, global agricultural production still needs to increase by 60% (and nearly 80% in developing countries) in the next four decades to cope with a 39% increase in population and increase global dietary energy supply beyond 3000 kcal per person per day. This translates into the additional production of almost one billion tons of cereals annually by 2050. In 2009,
Ghana among eight other African nations had the highest food supply of primary food crops, which ranged between 2730 and 3349 kcal/cap/day.
1.1.3.3. Food utilization
“Utilization is a measure of a population’s ability to obtain sufficient nutritional intake and nutrition absorption during a given period” (Hauck and Youkhana, 2008). The diversified poor meal is often associated with a deficiency in micronutrient, and it is a strong indicator for child stunting and maternal nutritional status (Ruel, 2003; Savy et al.,
2005; Ruel et al., 2010). Anemia caused by iron deficiency is known to be very common among individuals with meals low in animal protein and high in rice or whole wheat
7
(Banerjee and Duflo, 2011). Progress in food access and availability is not always associated with progress in food usage. Food handling, preparation and storage influence food utilization.
1.1.3.4. Food stability
This refers to the stability of availability, access, and usage at all times with no risks. The main risks which might have great effects on availability, access, and usage are extreme weather conditions, energy scarcity, economic and social disruption, and poor functioning global markets. Stability emphasizes having mechanisms in place in assuring the availability, access, and usage which is likely to change with risks. To address such risks, production systems need to be promoted and supported, ensuring sustainable investment in rural development, and improving market governance. The common factors associated with the stability parameters are focused on the availability and access parameters. Over the past 50 years, the world’s crop production has increased three times.
Growth in crop production corresponds to increase in crop yields in the arable land on which crops are planted which together with increases in crop intensification, such as higher multiple cropping, or reducing fallow periods, can lead to an expansion in the harvested area (Pangaribowo et al., 2013).
1.1.4. Food Security Situation in Ghana
A recent report prepared by MoFA (2015) discussed that 5% of Ghana’s population
(1.2 million people) are food insecure. The World Food Programme in 2009 reported that approximately 453,000 people in Ghana are food insecure with 34% in the Upper West region, 15% in the Upper East, and 10% in the Northern region (WFP, 2009). About two million people are vulnerable to become food insecure nation-wide, which means an unexpected natural or human-made shock will greatly affect the pattern of their food
8 consumption. People vulnerable to food insecurity totaling 1.5 million live in the rural and urban areas of the following seven regions of Ghana: Brong-Ahafo 11%, Ashanti 10%,
Eastern 8%, Volta region 7%, etc. The remaining 0.5 million people are found in the three
Northern regions.
Months of inadequate household food provisioning is defined as the time between stock depletion and the next harvest (Bilinsky and Swindale, 2007). Food insecurity in areas that are subsistence-oriented is measured using months of inadequate household food provisioning. Areas that are subsistence-oriented produce primarily for home consumption and only a few amounts of the products are sold in the market. Quaye (2008) reported that most farmer households experience a significant level of food insecurity lasting from 3 months to 7 months. Upper East Region was the worst affected because it experienced six months of food shortage (Nyanteng and Asuming-Brempong, 2003).
1.1.5. Strategic Plans to Reduce Food Insecurity in Ghana
To reduce food and nutrition insecurity, Ghana’s Ministry of Food and Agriculture outlined the following in 2012 (MoFA, 2012): i. Modernizing agriculture by improving productivity, mechanization, irrigation and water management. ii. Maintaining national strategic stocks such as food storage, distribution, and improved nutrition. iii. Preventing and managing emergencies and expanding national strategic stocks through effective early warning systems. iv. Enhancing peoples’ knowledge of the importance of optimum nutrition by improving advocacy on nutrition education and food fortification.
9 v. Reducing post-harvest losses, and improving storage and distribution systems through capacity building of relevant stakeholders. This includes proper methods for harvesting, primary processing, grading, storing, and ensuring good linkages between producers and markets. vi. Ensuring food production systems (macro and micronutrients and food fortification) as an essential aspect of food processing. vii. Reducing risks resulting from natural disasters and disease/pests outbreaks and ensuring adequate food stocks availability.
1.1.6. Ghana’s Food Security Achievements
Ghana economic growth has been resilient over the past three decades with an average yearly GDP growth of 4.5% since 1983, and appreciably 14% in 2011 (IFAD,
2012). This was attributed to a stable political environment and market reforms, the rise in prices of gold and cocoa, and a favorable environment for investments (World Bank,
2011a). Ghana has experienced high per capita economic growth rates, averaging 3.3% annually, mostly due to agriculture. At the same time, the per capita food production increased by 55% between 1990 to 1992, and 2008 to 2010. A Large part of Ghana’s population is experiencing the healthy GDP growth, averaging 5% per year since 2001, as extreme poverty declined from 51.7% in 1991 to 28.5% in 2006 (FAO/IFAD/WFP, 2015).
In just 15 years, about 5 million people have had improved situations and have moved from poverty level due to the broad sharing of rapid economic growth.
Growth in agriculture is more rapid than growth in the non-agriculture sectors in recent years. This growth expands by an average annual rate of 5.5%, compared to 5.2% for the whole economy. However, growth in agriculture heavily relies on rainfall patterns and land expansion. Ghana has made impressive progress towards the international hunger
10 targets and is among countries close to reaching global hunger targets. The more populous countries in Africa that have reached the MDG 1c hunger target, and WFP goal of halving the number of hungry people by 2015, includes Ghana, Angola, Cameroon, Mali, and
Gabon (FAO/IFAD/WFP, 2015).
1.2. Grain Cultivation and its Associated Problems: Overview of Ghana
1.2.1. Grains Cultivated in Ghana
1.2.1.1. Maize (Zea mays L.)
Maize is the principal staple crop produced and consumed in Ghana (fig. 1.2). It is produced predominantly by smallholder, poorly resourced farmers under rain-fed conditions. The crop is well adapted and grows in most of the ecological zones of Ghana including the northern savannah (Adu et al., 2014). Maize is grown in most part of Ghana although the middle to southern parts (transitional zone and forest zone) are the most grown areas (Rondon and Ashitey, 2011). The major source of calories in Ghana is obtained from maize and has nearly replaced traditional staple crops like sorghum and pearl millet in northern Ghana (SRID-MoFA, 2011). The average maize production per year between
2007 and 2010 was 1.5x106 Mg (Rondon and Ashitey, 2011). An average maize grain yield on farmers’ fields is about 1.7 t/ha versus an estimated achievable yield of about 6.0 t/ha
(SRID-MoFA, 2011).
In Ghana, maize planting is done in April or May, and the harvesting is done in
August or September for the major season. Maize accounts for over 50% of total grain output, although yearly yields have been growing meagerly by only 1.1%. In 2012, Ghana recorded 1.2–1.8 Mg/ha of maize yield which was less than the yield of 4–6 Mg/ha obtained in on‐station trials (IFPRI, 2014). There are some limiting factors to maize production in
Ghana which include drought during critical early stages of crop growth, low soil nutrient
11 levels (particularly nitrogen and phosphorus), striga, and pest and disease infestations. Poor management practices such as low plant populations, inappropriate planting time, inadequate control of weeds, lack of credit, limited use of inputs (especially fertilizer and improved seeds) as well as untimely application of adequate quantities of fertilizers, inadequate drying and storage facilities leading to high postharvest losses, and reduced market access are other limitations to maize production (Adu et al., 2014).
Maize grain is used predominately at domestic or household levels rather than industrial or commercial scale. All kinds of foods are prepared from maize grain, serves as a useful component in poultry and livestock feeds, and also in the brewing industry.
1.2.1.2. Rice (Oryza sativa L.)
It was estimated that Africa’s rough rice production was 14.6 million tons/year on
7.3 million hectares between 1989 and 1996 (Traore, 2005). Rice production remains at low levels although, West Africa has vast available areas and the largest planted rice area of about 4.1 million hectares. This could probably be attributed to improper crop management procedures, limited research and extension activities, and less use of improved varieties (Badawi, 2004; Anon, 2008). The average rice production in Ghana is
300000 metric tons, about 30% of the total rice required, and therefore the remaining 70% is imported. In 2013, 640000 metric tons of rice was imported into Ghana.
Rice (fig. 1.2) now competes with traditional staple foods, and rice consumption increases with population growth since rice continues to be part of the main meal in most homes as rice is relatively convenient to prepare, and has good taste. The fast-growing rate of fast food restaurants and vendors in the major cities is a contributing factor to the increased demand for rice. Most urban consumers prefer imported rice because of its higher quality, and about 76% of total rice consumed in urban areas is imported rice (MoFA,
12
2010). The yearly per capita consumption of rice from 1999–2001, and 2010–2011 was between 17.5 kg and 24 kg (IFPRI, 2014). According to MoFA, only 20% of locally grown rice is consumed in urban areas, with the rest consumed in rural areas. Domestic rice production and supply has not increased with the increasing demand for high-quality rice and the changing consumer preferences towards imported fragrant, long-grain white rice
(Rondon and Ashitey, 2011).
1.2.1.3. Sorghum (Sorghum bicolor)
Sorghum (a ‘grassroots’) is a traditional crop largely grown by subsistence farmers
(Offei et al., 2002). Sorghum (fig. 1.2) is mostly cultivated in the Guinea and Sudan savannah Zones in the Upper West, Upper East and Northern regions of Ghana with a respective average rainfall of 1000 mm and 990 mm per year. Sorghum is considered a staple crop food in Ghana, and are the baseline crops of farmers in the savannah zones.
Sorghum is third in rank after maize and rice concerning the quantity of cereal production, with 12% of total cereal production value. There is averaged increased yield from 0.9
Mg/ha to 1.2 Mg/ha although averaged yields of 2 Mg/ha are attainable (SRID-MoFA,
2004). Sorghum is not grown in large-scale, and only under the mercy of rain, and mostly in mixed cropping and intercropping systems. A limited amount of sorghum is important compared to other crops like maize and tomato grown in the four agro-ecological zones
(Diao et al., 2010).
Sorghum cannot be considered a major food security crop or a top-ranked cash crop. The lack of early sorghum varieties, insufficient or delayed rainfall, infertile land, limited seeds, attack by termites during storage, infestation by striga and black ants, insect- like mold-causing mirid head bugs (Eurystylus immaculatus) attack and diseases like smut are some pertinent reasons (Kudadjie et al., 2004). The three Northern regions where
13 sorghum is grown has about 40% of the population living below the poverty line (Asenso-
Okyere et al., 2000). Sorghum is resilient to drought and high temperatures which makes it crucial for food security in these regions (Kudadjie et al, 2004).
Sorghum consumption per capita started to increase between 2006 and 2007. The majority of farmers (69%) cultivate sorghum for their consumption only, 25% grow sorghum for both consumption and the market, and while very few (6%) grow sorghum for the market only. Sorghum has multiple uses as food, feed, and shelter. Sorghum grains can be milled and used to prepare food (“tuo zaafi”, porridge and “masa”) as well as a local alcoholic drink (“pito”), and the leaves can be used as fodder for farm animals, and the stalks are used for fencing, staking, roofing, weaving baskets and mats, and also for fuel.
Sorghum can be used as an adjunct or as the main ingredient in the brewing of beer.
Recently, breweries in Ghana are increasingly using malted sorghum as a substitute for barley. It is, however, worth noting that the appropriate malted sorghum potential demand from industries could reach up to 10,000 Mg/year. Brewery demand was estimated at around 2,500 Mg/year which is well below the potential. There is a limited supply of sorghum to brewery industries as Guinness Ghana is only getting 2% of the sorghum it requires (4000 Mg/year) for beer production (Angelucci, 2013).
1.2.1.4. Pearl millet (Pennisetum glaucum)
Millet crop is from the grass family, and the seeds are small and hard. Millets grow well in dry areas under rain-fed and less fertile and moisture conditions (FAO and
ICRISAT, 1996), making them the preferred cereal crop in drier areas (Kasei et al., 2014).
Millet (fig. 1.2) is known to be one of the oldest cereal crops for domestic use of humans.
Pearl millet domestication in northern Ghana dates back to about 1250 BC (Davies, 1968) or 1459 BC as reported by D‘Andrea et al., (2001). Pearl millet is grown mainly in the
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Northern, Upper East, and Upper West of Ghana (covering 29% of total land area), (SRID-
MoFA, 2011). Northern Ghana covers about 41% of the land area of Ghana and is located within the Sudan and Guinea Savanna zones (semi-arid zone or interior Savanna) (Bennett-
Lartey and Oteng-Yeboah, 2008).
The reason millet thrives well in Northern Ghana compared to other crops is that it produces grain yield under warm and dry conditions, and infertile and low water holding soils (CGIAR, 1996). Millet is first in importance as food and less in essence as a cash crop. It is a traditional crop grown by most households for food and sold only as a last resort for money. After prolong dry season, millet is the first crop to be harvested and so regarded as a hunger breaker (Kudadjie et al., 2004). In Ghana, Pearl millet is grown mainly as a food crop with the stalks used variously as fodder, roofing material, and fencing material or source of saltpeter for cooking traditional food.
1.2.1.5. Wheat (Triticum aestivum L)
There is some local production of wheat, but domestically produced wheat is less than a tenth of the total available supply. This cereal grows best in dry, and not too warm or too cold environments and therefore resulting in less domestic production. Ghana`s hot weather does not favor the cultivation of wheat (Effraim, 2013). Ghana is the fourth largest importer of wheat in the Sub-Saharan Region and the second largest importer of wheat from the U.S in the Sub-Saharan region (www.fao.org, 2000; Kessel, 1999). The importation of wheat is from Canada, Argentina, and the European Union and no more from the U.S. Wheat (fig. 1.2) has been long and commonly used as a cereal crop in Ghana.
Ghana has three major wheat milling companies having a total capacity of 1,600 tons/day, and operating at only 80% as a result of the stable consumption trend.
15
Wheat consumption was estimated to be approximately 300,000 Mg in 2010/2011, and the estimated per capita consumption was about 12.5 kg. Almost 80% of the wheat flour is used in bread making, while the remaining 20% is used in preparing cakes and other pastries. Demand by industries for soft wheat flour is increasing, but most of the flour is sold in the open market (Rondon and Ashitey, 2011). There is controversy over the credibility and source of the unbranded wheat sold at the open market (Effraim, 2013).
1.2.2. Grain Losses in Ghana
In considering increasing food production to feed over 9.1 billion people with safe food by the year 2050 (Parfitt et al., 2010), an important factor also to be considered is to reduce food loss and waste (Hodges et al., 2011). It is estimated that about 30% of the world’s produced food is lost or wasted (FAO-World Bank, 2010; Prusky, 2011). This loss is about 1.3 billion Mg per year in a world where over 870 million people go hungry
(Gustavsson et al., 2011). The World Bank (2011b) revealed that each year, substantial volumes of food are lost after harvest in sub-Saharan Africa (SSA), with an estimated value of USD 4 billion for grains alone. According to the report, the magnitude of food loss exceeds the value of total food aid received in SSA over the last decade, and also equivalent to the yearly cereal imports values to SSA. In addition, such losses are estimated to be equivalent to the annual caloric requirement of 48 million people. Experts are in recent times advocating for investing in postharvest loss (PHL) reduction to enhance food security
(GIZ, 2013a). Reports by the FAO and World Bank approximated that up to 47% of $940 billion needed to eradicate hunger in SSA by 2050 will be required in the postharvest sector
(FAO-World Bank, 2010). To alleviate poverty and improve nutrition require a drastic reduction in food losses.
16
The World Food Conference of 1974, resolved to bring about a 50% reduction in
PHL by 1985 (Parfitt et al., 2010). Although some approaches have been employed to reduce PHL, limited success has been achieved (World Bank, 2011b), an indication that these approaches have not yielded compelling results in SSA. PHL between 10 and 40%, and as high as 50 and 70% are usually reported (FAO-World Bank, 2010; Kader, 2005;
Lundqvist et al., 2008; Parfitt et al., 2010; Prusky, 2011), and also most often from unknown sources. Moreover, reports and several other studies (FAO-World Bank, 2010;
Gustavsson et al., 2011; Parfitt et al., 2010; Prusky, 2011) also indicate the existence of major data gaps in quantifying PHL in SSA. In Ghana, the trend of marketing is a contributing factor to PHL. This is because the producers are mostly not part of the marketing chain and rather sell the grains at the farm gate to traders from the city markets.
The grains are then sold wholesale or retail in urban markets (Rondon and Ashitey, 2011).
According to the World Bank (2011b), losses can occur (i) at harvest, (ii) during conditioning, (iii) at handling, (iv) during transportation and distribution, (v) at storage due to pests, spillage, spoilage, and contaminations, (vi) during processing due to inefficient technologies, and finally, (vii) during marketing.
A significant increase in the food supply in Sub-Saharan Africa could be achieved by investing in reducing post-harvest food losses (World Bank, 2011b). The creation of
National Food Buffer Stock Company (NAFCO) was part of the Government of Ghana strategy in reducing post-harvest losses, ensuring price stability, and establishing emergency grain reserves (Rondon and Ashitey, 2011). NAFCO is a state-owned enterprise intended to buy, preserve, store, sell, and distribute excess grains in warehouses across the country. The recent world food and financial crises have necessitated focusing on post-
17 harvest losses. PHL of 20% or more is unacceptable for Ghana, and Africa in grain production (World Bank, 2011b).
1.3. Maize in Ghana: An Overview of Cultivation to Processing
1.3.1. Areas of Cultivation
The agro-ecological zones for maize cultivation in Ghana can be mainly grouped into four (fig. 1.3). The system of maize cultivation differs among these agro-ecological zones (Morris et al., 1999).
1.3.1.1. Coastal Savannah zone
The coastal savannah zone comprises a narrow belt of savannah that runs along the coast and widens towards the east side of Ghana. Maize mostly intercropped with cassava is grown by farmers. This zone experiences bimodally distributed annual rainfall totaling around 800 mm, and maize planting normally begins at the onset of the major rainy season
(March or April). Low productivity has been reported due to light soil texture and low fertility.
1.3.1.2. Forest zone
The forest zone lies down just inland the coastal savannah. Most of Ghana’s forest is semi-deciduous, with a small area of high rain forest in the South-Western part of the country close to the border with Côte d’Ivoire. The cultivated maize is mostly intercropped with cassava, plantain, and cocoyam. The annual rainfall averaging about 1,500 mm is observed, and maize is planted both in the major and minor rainy seasons (March and
September respectively).
1.3.1.3. Transition zone
The forest zone gradually gives way to the transition zone towards the Northern part of Ghana. This zone is an essential area for commercial grain production and is
18 characterized by thick, friable soils, and the relatively sparse tree cover allowing for progressive cultivation. Annual rainfall averaging about 1,300 mm is bimodally distributed. Maize cultivation is done both in the major and minor rainy seasons mostly as a monocrop or intercrop.
1.3.1.4. Guinea savannah zone
Most of the lands in the Northern part of Ghana are in this zone. There is a single season of rain per year averaging 1,100 mm. Although sorghum and millet are the predominant cereals, maize is equally grown. Maize can be intercropped with legumes and other crops. Generally, maize production happens in almost every part of Ghana, but more than 70% of the maize output is from three of the agro‐ecological zones (guinea savanna, forest zone, and transition zone). The five principal maize growing areas are in the
Northern, Brong‐Ahafo, Ashanti, Central and Eastern Regions (Amanor‐Boadu, 2012).
1.3.2. Consumption and Cost of Maize
Reports indicate that 90% of the world’s calorific requirement is provided by only thirty crops, with wheat, rice, and maize alone providing about half the calories consumed globally (MA, 2005b). The per capita consumption of maize in Ghana in 2000 was estimated at 42.5 kg (MoFA, 2000) and estimated national consumption of 943000 Mg in
2006 (SRID-MoFA, 2007). One million metric tons of maize is reported to be marketed annually in Ghana. A substantial quantity of maize grains produced (table 1.1) remains within households of producers as a primary staple food (Gage et al., 2012). The maize grain is consumed in different forms in various traditions and cultures, and a large proportion of the maize is used in the poultry industry as feed. Only about 20% to 25% of the total maize marketed is used for industrial processing and purposes. The wholesale
19 price of maize is dependent on proximity to markets (location and transport), and the year’s season, with prices generally high during the off seasons (Amanor‐Boadu, 2012).
1.3.3. Post-Harvest Handling and Losses
Quality cannot be compromised in the agricultural production chain, and post- harvest handling of produce is a critical factor in determining standards and quality. Post- harvest handling involves the management of produce before processing which involves drying, storage, protection against pests, and moisture regulation. This step importantly requires quality control processes, a key in competitive products marketing. There has been the application of traditional methods since olden days to preserve produce until the emergence of modern, and advance post-harvest techniques. The benefits of modern post- harvest handling are many, and most farmers in Ghana appreciate these processes.
Ragasa et al. (2014) reported that maize accounts for 50% of the total cereal production in Ghana, and reportedly has postharvest losses of between 5% and 70%
(FAOSTAT/FAO Statistical Division, 2012). To improve food security, there should be a reduction in PHL. Because losses increase the cost of products and thereby reducing consumers’ purchasing power, divert income out of farmers’ pockets, and hinder food availability (Opit, 2014). This report also indicated that the amount of grain stored in warehouses in Ghana is rapidly increasing, and some private and public sector organizations have formed Postharvest Service Centers (PSC) to increase agriculture production, food quality and reduce PHL. The grains held by PSC are stored in warehouses and are virtually not given protection from insects and pests, and atmospheric air.
The National Food Buffer Stock Company (NAFCO) purposely created by Ghana’s
Government was to reduce post-harvest losses, ensure price stability, and establish emergency grain reserves (Rondon and Ashitey, 2011). NAFCO is a state-owned enterprise
20 buys, preserves, stores, sells, and distributes excess grains mostly maize in warehouses across the country. Africa and Ghana cannot afford to experience 20% or more grain PHL
(World Bank, 2011b).
1.3.4. Post-Harvest Storage Methods
Stored maize can be attacked by 20 different species of insect pests including the maize weevil, Sitophilus zeamais (Mots.) (Coleoptera: Curculionidae), and the larger grain borer (LGB), Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae). It has been reported that 90% worldwide postharvest losses are due to insects, and mite infestation; and therefore the need to control them (Vachanth et al., 2010). Owusu-Akyaw (1991) reported that about 20% of maize and cowpea produced annually are lost to S. zeamais.
The produce can be contaminated with insect bodies and frass, and toxic chemicals like quinines (Kabir et al., 2011). There are various traditional and modern techniques used for storing the maize grains or cobs.
1.3.4.1. Traditional techniques
Maize drying is to allow a moving, relatively less humid and dry air takes moisture away from the grain.
1.3.4.1.1. In-field drying
The cobs may be stacked or ‘stooked’ in the field to allow for further drying. Further losses are likely to happen due to more scattering, and exposure to pests and insects.
1.3.4.1.2. On-platform drying
Threshing of grain is mostly preceded by further drying in homesteads. The maize cobs may be hung on racks or placed on purposely constructed platforms (fig. 1.4). This method has many advantages compared to the infield drying, but the percent of grain loss is relatively high.
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1.3.4.1.3. On-ground drying
The grains are typically spread out on the ground floor to allow drying (fig. 1.5).
The grains which may be on the bare floor could absorb moisture, be contaminated with dirt and foreign materials, and also be exposed to rains, insects, pests, livestock, and birds.
In recent times, people are commonly drying maize on plastic sheets or mats. This practice of ground floor drying is discouraged because of the following reasons (Proctor, 1994;
World Bank, 2011b):
• Have to keep watch all the time to keep the grains from rain, etc.
• Grains can be washed away when there is a sudden downpour or be brought under shelter at night or when about to rain.
• There is a higher risk of contamination from dust, soil, stones, animal droppings, fungal, and insect infestation.
• Losses from birds, poultry, and domestic animals, and quantitative losses are very high.
• The method is time-consuming and can be labor intensive when the harvest is huge.
Unfortunately, this method is the most practiced by farmers.
1.3.4.1.4. The use of mud silos
The use of mud silos was commonly practiced in the Northern part of Ghana (fig.
1.6). These silos are constructed with mud and roofed with grass straws in which the grains are kept for storage. Considering the different methods discussed, this method is the best, but losses are still relatively high.
1.3.4.2. Modernized techniques
1.3.4.2.1. The use of metal silos
Farmers now store grains relatively safe in affordable metal silos (fig. 1.7). These metal silos minimize or prevents to a larger extent exposure to pests, insects and the
22 weather conditions, and help increase food security (Proctor, 1994). The relatively high costs of the metal silos are a challenge now because the smallholder farmers consider it expensive to buy as an individual (FAO, 2008).
1.3.4.2.2. The use of solar dryers
Solar dryers help reduce grain moisture to a safer level, and therefore storage can be done safely for quite a longer period (Heinz, 1995). Solar drying can be used to dry all food types, and it is considered an effective preservation technique in Africa. More importantly, the solar drying operates in a clean, and sanitary environment with minimum labor and space required. Like metal silos, solar dryers are relatively expensive, and therefore not priceworthy to be owned by individual farmers (Balakrishnan, 2006). Some farmers’ cooperative could own solar dryers to be shared among members to reduce costs
(FAO, 2008).
1.3.4.2.3. The use of chemicals
Farmers sometimes have to turn to the use of chemical control methods despite the associated health issues.
1.3.4.2.3.1. The use of fumigants and contact insecticides
Gaseous fumigants and residual contact insecticides are mostly used to control insects in stored grains (White, 1995; Obeng-Ofori, 2007 and 2011). The dried grains are fumigated and then packed into bags for storage. Fumigants are reported not to be having a residual effect but can penetrate through stacks or bulk product killing all life stages of insects. The major drawbacks in the use of fumigants are that they do not protect against grain reinfestations, they are extremely poisonous and could result in death if not well- handled (Danilo, 2003).
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1.3.4.2.3.2. The use of layer by layer dusting of maize cobs (sandwich method)
The dried, and well-cleaned maize cobs are treated layer by layer as they are put into the granary. This treatment is effective against most traditional storage insect pests of maize but relatively less effective in controlling large grain beetle. Some recommended chemicals used are Actellic 1%, Malathion 2%, Malathion 2%, Etrimfos 1%, Gardona
3.25%, and Methacrifos 2% (Danilo, 2003). The development of resistant insects’ strains and health hazards to grain handlers could broadly be attributed to widespread and overdose use of synthetic chemicals (Zettler and Cuprus, 1990; White, 1995; Obeng-Ofori et al., 1998). Annual cereal grain losses could be up to 50% even with the heavy chemical usage although the average losses stand at roughly 20% (Obeng-Ofori, 2011). Misuse of insecticides by farmers is predominant, and health and environmental problems are inevitable (Baributsa et al., 2010).
1.3.4.2.4. The use of the hermetic technique
To overcome the problems associated with fumigation and insecticides use, hermetic (airtight) storage technology is the most appropriate method. Calderon and
Navarro (1980) pioneered modern hermetic storage in Ghana which consisted of a sealed storage system containing a modified atmosphere. This technique is based on the principle of creating oxygen depletion and increasing carbon dioxide in the ecological system of sealed storage structure (Navarro et al., 2001; Obeng-Ofori, 2011). Research has shown that hermetically stored grains maintain their freshness and taste, seeds maintain their vigor and the ability to germinate. The first triple-layer hermetic bags used in Ghana was developed by Purdue University (fig. 1.8) and was effective in storing cowpea. The Purdue
Improved Cowpea Storage (PICS) bags consists of two sealed plastic (polyethylene) bags placed inside a third woven nylon or polypropylene bag for strength. These bags are now
24 called Purdue Improved Crop Storage (PICS) bags used for storing all sorts of grains including maize. The effectiveness of the PICS bag in controlling Sitophilus zeamais (Mot) has been tested in Ghana. The results showed that the PICS were effective against S. zeamais and can be used for grains storage (Anankware et al., 2013).
1.3.4.2.5. The use of Purdue Improved Drying Stove (PIDS)
Farmers who primarily depend on open-air sun drying are faced with challenges as harvesting coincides with the minor rainy season. Grains not dried to safe moisture levels cannot be efficiently stored using PICS technology. To enhance drying and quality of grains, and also not to compromise the credibility of the use of PICS bags, the PIDS (fig.
1.9) was tested in Ghana (Ileleji, 2012).
This technology was tested and is not for commercial use although the technology is being improved. This technology works on the principles below:
• It combines an efficient cooking stove and crop dryer in one unit.
• The concept is an indigenous idea but optimized with engineering.
• Maize cobs are used as fuel to reduce drying energy and save firewood use.
Some observed setbacks which limited the use of this technology were: a. The production of smoke and coloring from soot. b. Controlling heat loss and maintaining a target temperature of 60°C in chambers 1 and 2 was a challenge. c. Wind control during the operation was a challenge. d. There is the need to understand the use of different biomass fuels, and also to model using CFD (computational fluid dynamics) to understand heat transfer dynamics.
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1.3.5. Shelling and Cleaning of Grains
The most recommended way to store maize is in a shelled form. In many rural areas of developing countries including Ghana, the maize kernels are shelled mostly by using the fingers. Shelling the harvested maize by hand (fig. 1.10) typically takes weeks. The shelling becomes painful and causes injuries to fingers when the kernels are hard to shell. In situations where harvest is huge, shelling is commonly done by loading maize cobs in sacks, and the loaded sacks are beating with sticks. The beating may result in physical damage to the grains making the grains more vulnerable to pests and molds, and also causes germ damage. The use of industrial maize shellers and small-scale hand-cranked or pedal- powered maize shellers are often unaffordable or difficult to obtain by subsistence farmers.
Simple tools have been developed to make it possible to shell maize several times faster than by the fingers. These tools have been developed in different types and sizes using locally available materials (fig. 1.11). Recently, some individuals own shellers that render services to farmers. The owners operate in the act of barter trading, where they take one bag out of the total of ten shelled bags. Cleaning of shelled grains is an important step to consider, and this is done by winnowing which involves letting the grains drop from a height and allowing natural air to carry the chaff and foreign materials out of the grains.
This method, however, is time consuming, tedious, inefficient and causes grain losses.
Grain cleaning makes the grains wholesome, increases market value, and reduces mold and insect development.
1.3.6. Transport of Grains
Maize grain transport is equally an arduous task, and the process also can result in insects and microbial contamination. The harvested maize cobs are moved to the farmyard from the farm. The shelled grains are also transported from farmyards to various markets.
26
Women and children are those who usually carry the produce either on their heads or shoulders to the various destinations. Harvested grains can be carried from fields or farm yards to different destinations by using motor trucks or cars, but this is dependent on the availability of access roads and the costs affordability of the farmer. The means of transport also depends on factors like the quantity of produce, distances to be covered, the availability of motor trucks (Danilo, 2003). The degree of grain deterioration during grain transport is mostly proportional to the distance to cover.
1.3.7. Grain Processing
The growth in processed food sale is about three-quarters of total world food sales.
Processed food makes up about half of the total food expenditures in developed countries, whiles in developing countries it comprises only a third or less (Regmi and Gehlhar, 2005).
Domestic use of maize is greatly predominating industrial processing of maize in Ghana.
Besides boiling or roasting of the whole fresh maize cob as a meal, fermented meals prepared from maize are commonly eaten in most homes. Some examples of fermented maize meals in Ghana are “koko” (porridge), “banku”, “tuo zaafi”, “akple”, “kenkey” etc.
Poultry and livestock feed prepared from maize are the major industrial processing, and a limited quantity of maize grains are processed onto shelves. The limited commercial or industrial processing of maize is causing tremendous food insecurity in Ghana. Tons of maize were wasted in barns and warehouses in the Northern Region of Ghana following a glut in the market (Ghanaweb.com, 2013) which has been the phenomenon for decades. A glut in the maize market sometimes leaves many farmers impoverished as they are forced to sell their produce cheaply due to lack of proper storage facilities and industrial processing. It is also worth noting, the extent of grain rot in stored barns and warehouses during seasons of a glut in maize.
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1.4. Deterioration of Stored Seed: A Review
1.4.1. Seed Quality, Vigor, and Viability
A good seedling mainly depends upon a good quality seed. Good quality seeds under proper management practices reward higher production or yield. Good quality seeds have high vigor, uniformity, structural soundness in addition to inherent genetic and physical purity (Hussian et al., 2014). The protein content of seeds also determines its vigor, increased in protein makes seeds vigorous (Warraich et al., 2002). Seeds storage reserves are also important scale in seed quality which influences germination, seed vigor, seedling establishment, and yield. The initial seed quality before storage may be influenced by factors like seed harvest maturity, conditions during storage, mode of handling, and probably previous viability lost before storage. Seed germination rate is affected by seed aging during storage (Bewley et al., 2013). Any deterioration can be observed in the percent reduction in germination rate, reduction in seed vigor and viability, subsequent seed death, and production of weak seedlings (Tilebeni and Golpayegani, 2011).
1.4.2. Abiotic Factors Resulting in Seed Deterioration
Various factors can influence seed longevity in storage, but seed MC, ERH, and temperature are most important (Lawrence and Maier, 2010; Bewley et al., 2013). During post-maturation and pre-harvest period, high relative humidity and temperature could cause seeds to deteriorate in quality, vigor and viability, thus field weathering (Bhatia et al., 2010). Weathering lapse between onsets of physiological maturity and harvesting in the field. In the field, the seed physiological quality is affected by the environmental factors that precede the time of harvesting (Pádua et al., 2009). Harsh environmental factors (high temperature and humidity) at the stage of seed filling and maturation may hasten the maturation of seed. This leads to a significant decrease in seed quality, and low crop yields
28
(Pádua et al., 2009). At low temperature and humidity, seeds viability is conserved for longer periods as deteriorative processes are delayed (Mohammadi et al., 2011). Delaying harvesting, particularly if seed moisture is high extends field exposure and intensify seed deterioration (Khatun et al., 2009; Bewley et al., 2013). Drying of high MC seed at very high temperatures also affects seed quality. However, during storage seed damage is inevitable (Balesevic-Tubic et al., 2005).
1.4.3. Biotic Factors
Biotic factors particularly molds (fungi) and insects influence longevity of seed in storage. The two fungi types that attack seed are field fungi, and storage fungi. Field fungi affect seed in the field prior to harvesting, and during storage fungi attack seed. Field fungi
(e.g., Fusarium spp.) thrive in high moisture environments such as rainfall at the time of harvesting or high moisture level of seed (Bewley et al., 2013). Storage fungi (Aspergillus spp.) thrive best when moisture levels of seed are low. Storage fungi do not establish on seed with MC in equilibrium with less than 68% ambient RH (Bewley et al., 2013).
Therefore, when moisture content, temperature, and relative humidity are low, the risk of fungi invasion is minimized. These fungi produce harmful stuff that is injurious to seed cells and cause seed deterioration. Inadequate drying of seed can favor the growth of molds or fungi, hence a decrease in seed quality or quantity. Deterioration by bacteria is limited as they require free water to grow. Storage bacteria are active around 90% RH where fungi are already very active (Malik and Jyoti, 2013). Reed et al., (2007) indicated that high initial MC is favorable for high seed infection. Insects and mites could seriously attack stored seed when there is warm and humid storage environment. Insects are inactive below
8% and active around 15% seed moisture content. Different kinds of insect pests make maize seed vulnerable but the commonest insects pest is Sitophilus zeamais, and Sitophilus
29 oryzae also attack rice seeds. Rodents attack stored seeds when the seeds are not kept in properly shielded places to prevent rodents’ access.
1.4.4. Lipid Peroxidation (Biochemical) Deterioration of Stored Seeds
The physiology of a seed is influenced greatly by its biochemical constituents.
During storage, the biochemical constituents such as carbohydrate, protein and oil contents decrease, and arise in free amino acids, free fatty acids, and electrical conductivity is observed (Ameer et al., 2013).
Lipid peroxidation occurs in polyunsaturated fatty acids in the presence of oxygen during storage (Smith and Berjak, 1995). Peroxidation (auto-oxidation) is generally initiated when the moisture content is low, and auto-oxidation reduces in effect with increasing moisture. This is because water limits access to oxygen by sensitive sites as metal ions are hydrated, and also catalytic effectiveness is lowered. Because of this, the diffusion efficacy of chelators and antioxidants are increased, and the hydroperoxides decomposition is constrained by hydrogen bonding (Kappus, 1991). The primary cause of seed deterioration is linked to non-enzymatic peroxidation activity of free radicals and may cause damage to seed membrane (Sung and Chiu, 1995). Reports have indicated that seed quality parameters decrease with increasing storage period and biochemical changes (Goel et al., 2003; Loycrajjou et al., 2008; Cakmak et al., 2010; Ameer et al., 2013).
Polyunsaturated fatty acids experience spontaneous oxidation if oxygen is present.
This produces a very reactive intermediates free radical (hydroperoxides). Hydrogen (H-) is first abstracted from a methylene group (-CH2-) next to a double bond. Peroxy radical
(LOO-) is formed after getting diene conjugation and oxygen reactions. The peroxy radical reacts with another unsaturated fatty acid (LH) to form a primary oxidation product (lipid
- hydroperoxide, ROOH). Lipid peroxidation using superoxide anion radicals (O2 ) occurs
30 within hydrated, and metabolically active systems. Highly potentate oxidant (hydroxyl radical, OH-, and single oxygen) are formed from the reaction between superoxide and
H2O2. The potentate oxidant could initiate great destruction in larger polymers and membrane lipids. The lipid peroxidation chain recycles when hydroxyl radical abstracts hydrogen from a lipid methylene group (Górecki et al., 1996).
Seeds have defense mechanisms in tissues which protect them from lipid peroxidation and free radicals production. Natural antioxidants (tocopherols (vitamin E), ascorbate, glutathione, and b-carotene) play an effective role in quenching superoxide (O-
2) and lipid peroxy radicals (Górecki et al., 1996).
The cellular function is affected in several ways by lipid peroxidation. Peroxidation of membrane lipids makes them dysfunctional, DNA is denatured, and hence mRNA to proteins translation is constrained. The nature of proteins is greatly influenced based on hydration levels. Protein-protein crosslinking occurs between lipid hydroperoxides and proteins interactions at relatively high moisture content. Browning reactions occur as aldehydes (lipid breakdown products) form covalent bonds with proteins. Peroxidative degradation is most prevalent in long-term storage, but not always before viability is lost.
Signs of lipid peroxidation are unlikely to be exhibited when seeds age under high humidity conditions (Górecki et al., 1996).
1.4.5. Resulting Effects of Seed Deterioration
Seed deterioration causes considerable damage to seeds. Some prominent effects of the deterioration are reduction in the percent seed emergence and germination, seed vigor and viability is lost, membrane integrity is lost and subsequent solute leakage, reduction in biosynthesis and energy producing ability (respiration), reduced germination rate and loss of seedling vigor (abnormal seedling), low growth uniformity, and reduced
31 storage potential (Malik and Jyoti, 2013) resulting in food insecurity and putting farmers in financial constraints.
1.5. The Use of Synthetic and Botanical Insecticides in the Treatment of Maize Grains in Ghana: A Review
1.5.1. Reasons for Maize Treatment after Harvesting
Harvested grains are highly susceptible to deterioration if they had previously not been infected on the field. Various techniques are employed to protect grains from PHL categorized into quality, quantity, and economic losses (Tefera, 2012; Zorya et al., 2011;
Kader, 2005) from possible attacks of insect, diseases, rodents, and pathogenic microorganisms.
Mihale et al. (2009) reported that in developing countries insects can cause pre- harvest and post-harvest losses of 15% to 100% and 10% to 60% respectively of grains.
The principal causative agent of field and storage losses are insect pests (Suleiman et al.,
2013). Farmers store grains with the purpose of having access to food till future harvest season, getting seeds for next planting season, and selling at attractive prices on a later day.
Stored grains are most seriously under the attack of insect pests causing severe economic damage. Some of the common insect pests are S. zeamais, S. oryzae, etc. (Gitonga et al.,
2015).
Molds and fungi can attack grains in storage and cause catastrophic losses. Fungi growing on stored grains can produce deadly toxins (mycotoxins), making the grains unsuitable for food or feed. Rodents can greatly cause damage to cereals qualitatively and quantitatively (Mdangi et al., 2013). They are capable of causing qualitative losses of grain through discoloration, and physical contaminants including furs and excreta (Brown et al.,
2013c).
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To alleviate poverty, we need to reduce food insecurity and poor nutrition and increase income levels of smallholder farmers in developing nations (Shiferaw et al., 2011;
Affognon et al., 2015) by reducing post-harvest losses using the appropriate allowable storage time. Strategies employed to minimize PHL in should be comprehensive than storage techniques (Affognon et al., 2015). However, to reduce if not to eradicate post- harvest losses, treating grains before they are stored is almost inevitable.
1.5.2. The Various Techniques Used in Treating Maize Grains during Storage
Precautions are needed to maintain the quality and quantity of newly harvested grains to prevent losses. It is recommended that grain moisture content is reduced as early as possible through drying. Environmental conditions like relative humidity and temperature should also be controlled during storage. Additionally, application of chemicals to grains before and during storage should be done.
Insect pests can cause about 10% of harvested food loss in storage (PSE, 2016).
Hence, to increase food resource availability grains should substantially be protected from insect pests. Damages associated with insects are typically accompanied by molds attack as the insects produce heat and water to provide a favorable environment for survival and deterioration by storage fungi. Therefore, adequate grain protection is provided by preventing insect infestation by chemical application. The chemical application can be for preventing or controlling insects attack. To achieve effective prevention of insect infestation, thorough sanitation should be practiced.
The following are practiced, residual insecticide treatment for long-term storage
(more than nine months) and fumigation (insecticides and fumigants). Storage areas could be fumigated to keep insects away, kill existing insects, and keep grains from subsequent attack. Some of these chemicals prevent molds and bacterial activity. Although grain
33 protectant may be applied, the grain is not 100% protected from insect infestation.
Chemicals may be applied again during storage, and these chemicals are usually fumigants.
The diffusing fumigants (gas) penetrates the product and respiratory system of insects. One commonest fumigant used is phosphine.
These chemicals can be applied as residual spray on the floor and sides of storage facility (Malathion), grain protectants (Actellic 5E), surface treatments or topdressing after the bin is loaded (Methoprene (Diacon II)), bin headspace (Dichlorvos resin strips), and fumigation (Aluminum phosphide) (PSE, 2016). Smallholder farmers in Ghana mostly use
Actellic Super (Pirimiphos-methyl and Permethrin) dust (Obeng-Ofori, 2010). This chemical is effective when the right dose is used, although it may not be commonly available in some rural areas. The problem may be the possibility of it been adulterated by unscrupulous traders (Stevenson et al., 2014).
Herbal and aromatic plants contain essential oils that are one potentially important source used to treat grains. Essential oils have proven to be potent fumigants to control many insects during storage (Benzi et al., 2009; Ebadollahi et al., 2010; Christian and
Goggi, 2008). Essential oils are secondary metabolites in plants having strong aromatic compounds (Koul et al., 2008). The composition of essential oils is complex and vary with the period of harvesting, geographical region, planting conditions (Van Zyl et al., 2006), and method used in extracting the oil (Yang et al., 2005).
1.5.3. Industrial Production of Chemicals Insecticides and Related Health and Environmental Issues
Agrochemical use in Ghana is growing, and it is part of Ghana’s agricultural successes. Pesticides used in Ghana are mostly imported with very few local productions
(Fianko et al., 2011). About 80-90% of Ghanaian farmers are estimated to use pesticides
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(NPAS, 2012). Per the contribution of the agrochemicals industrials, Ghana’s government has therefore allowed tax exemptions for foreign enterprises engaged in pesticide production and trade for at least five to ten years. Mechanical equipment imported by foreign enterprises for personal use is also exempted from import duties, sales, and license tax. In 2011, pesticide dealers in the pesticide market were estimated to be around 6,000
(International Business Daily 2011). According to the World Health Organization (WHO),
20% of the world’s pesticide use is located in developing nations, and this poses environmental and health threats (Hurtig et al., 2003). Large concentrations of pesticide contaminate were detected among families located in agricultural areas (McCauley et al.,
2001), and closer to farming fields (Quandt et al., 2004). According to the Northern
Presbyterian Agricultural Services, in 14 farming villages over 25% and 20% of farmers suffered from the direct inhalation of chemicals and spillage of chemicals on the body respectively (NPAS, 2012). Organochlorine pesticide residues like dichlorodiphenyltrichloroethane (DDT) were detected in blood and breast milk of farmers that cultivate vegetable in Ghana (Ntow, 2008). There are also some environmental issues when it comes to the application of pesticides. There are chemical and biological insecticides to control insects, and these insecticides have their active and inert ingredients.
The active ingredients have the potency of killing the pests. Synthetic insecticides commonly in use are chlorinated hydrocarbons, organophosphates (widely used), and carbamates.
In the production of insecticides, active ingredients, solvent, and emulsifiers are the raw materials needed for the formulation (fig. 1.12). Typically, other elements like catalyst and packing material are needed for the finished product. The production also requires
35 utility inputs like electricity and water. The active ingredient is fed into the formulation plant using a feeding screw conveyor or siphoned pump. Similarly, the other required materials are then released into the jacketed kettle. Controlled heat is applied to the mixture while stirring until obtaining a homogeneous mixture. A stable homogeneous mixture consisting of active and inert ingredients is to be formed. The holding tank receives the formulated products which enter the packing machine, and automated capping and labeling machines. Precautionary measures are employed during production to suck volatiles with a vacuum system. This sucked volatiles are then passed through the activated carbon packed column to be filtered before releasing into the atmosphere. The collected waste is then evaporated using solar heat, and the solid is incinerated or buried in a landfill.
1.5.4 Industrial Production of Natural (Essential Oils) Insecticides and Related Health and Environmental Issues
Aromatic plants in the Mediterranean and tropical countries are reported to contain essential oils. Essential oils are almost distributed across all plant organs of aromatic plants
(Burt, 2004; Pandey et al., 2014). Essential oils may contain different concentrations of about 20-60 components. Essential oils are distinguished by their high concentrated (20% to 70%) major constituents (Pandey et al., 2014). The larger compositions of essential oils have the potency to be used as a botanical pesticide. Essential oils in recent years have become alternative pest control insecticide to synthetic insecticides. Essential oils are specific against insect pests, biodegradable, and commercially applicable (Park et al.,
2003). The potency of essential oils has been tested on some bruchid pests (Owusu, 2001;
Tripathi et al., 2002; Odeyemi et al., 2008; Asawalam et al., 2008b; Matta, 2010; Danga et al., 2015). They have different modes of actions depending on the major chemical constituents and insects’ susceptibility (Isman, 2000). Different kinds of essential oils have
36 been tested against various insects, and there were differences in oil potency depending on doses applied and the various experimental situations. According to Souza et al. (2008), the insecticidal effect is in the range of 20% to 60% within five days per the plant extract.
Different formulations of Niger seed oil and 5% Malathion dust protected maize seed against S. zeamais for about 90 days (Yuya et al., 2009). Many research has indicated that the major components of these oils are effective alternatives to synthetic fumigants (Lee et al., 2001a, b; Velluti et al., 2004; Lee et al., 2005; Mahfuz and Khalequzzaman, 2007;
Somda et al., 2007; Christian and Goggi, 2008; Adjei, 2011). Some essential oils have antifungal activity (Burt, 2004; Natarajan et al., 2003; Joshi, 2006).
There are different methods used in extracting essential oils from plant materials.
The methods include maceration (oil vegetable solvent used), cold pressing (for citrus), solvent extraction (hydrocarbon solvent used), enfleurage (intensive, traditional way of extracting oil from flowers, alcohol solvent), hydrodistillation (primitive countries), carbon dioxide and supercritical carbon dioxide extraction (most modern technologies, CO2 solvent), turbo distillation (for coarse plant material), and steam distillation (most commonly used).
The most commonly used method of essential oil extraction (steam distillation) is explained under this section. Steam distillation is for temperature sensitive materials that are insoluble in water and decomposes at their boiling point. The components of essential oils can have boiling points reaching 200°C or above. However, distilled substances volatilize during steam or boiling water at around 100°C. Botanical material (Fresh/dried) is fed to the plant chamber (fig. 1.13). The material is softened by the steam passing through the cells, and the essential oils are then vaporized. At high temperature, the steam cause
37 enough oil to evaporate. The evaporated tiny droplets of essential oil, and steam molecules through a tube are condensed and collected into the still's condensation chamber. Decanting or skimming off the top film separates the essential oil from the water. The distillation byproduct (floral water or hydrosol) may harbor many of the therapeutic properties of the plant material. The plant material, distillation time, temperature, pressure, and the quality of the distillation equipment determine the final quality of a steam distilled essential oil.
Precautionary, chamber's pressure and temperature should not be excessive to prevent oil constituents from being altered or destroyed. Steam distillation is relatively a cheap process, basic to operate, and the oils produced have known properties. Gas chromatography is used for identifying the composition of essential oils, and to separate the oil components the GC is fused with silica capillary columns.
Essential oils are specific in action against insect, biodegradable (environmentally friendly), and commercially applicable (Park et al., 2003).
1.5.5. Industrial Preparation of Powdered Botanical
This example provides a process (Sankaram et al., 1999) for preparing a dry powdered extract of about 88% of azadirachtin from a neem plant material (seeds). The neem seeds are disintegrated into powder, and the powder is subjected to a batch of continuous percolation in a column at a favorable temperature using the appropriate alcohol derivative. The concentrated extract is stirred with petroleum ether or hexane to separate the phase (boiling point 60°C to 80 °C). The dense azadirachtin-containing phase is stirred in a water-insoluble organic solvent, and then the phase is conventionally separated. Upon concentration petroleum ether or hexane is added to the organic phase at ambient temperature while stirring. The azadirachtin dissolved in the petroleum ether or hexane is
38 subjected to open column chromatography to make up to 49% powdered azadirachtin.
HPLC is used to enrich the powder to 88%.
1.5.6. Comparing Hazards and Challenges of Using Synthetic and Botanical Treatments
The effect of seed treatment is one of the several factors that influence the cost, risk, and benefits of seed treatments. Synthetic pesticides are the most used chemicals against grain pest infestation. Synthetic pesticides have many detrimental effects on insect pollinators, aquatic organisms, and humans and animals. There are also reports about insect resistance to pesticides (Mahmud et al., 2002), increased susceptibility of crops to insect pests (Pimentel, 1977), and this has made high the cost to control the environmental and social damage (Pimentel et al., 1980). In Australia and India, resistance to phosphine is very high which is likely to fail to control insects (Leelaja et al., 2007). At least there are reports of about 500 species of insects and mites that are resistant to pesticides (Georghiou,
1990). Report by WMO (1995) identified Methyl bromide as a greenhouse gas causing ozone depletion, and in developed countries, it has been banned, and developing nations were to phase it out in 2015.
The challenges outlined above have called for more effective alternative biodegradable natural pesticides which have wider selectivity. Natural insecticides being biodegradable, are also less toxic to mammals. However, plant compounds can be toxic; hence research seeking non-toxic compounds are ongoing (Yingjuan et al., 2008). Natural and cheaper method for controlling cereals storage pests in Ghana was to use plant materials Owusu (2001). Income of rural farmers is increased through the sale of safe and quality product as natural insecticides are used (Obeng-Ofori, 2007; Rajashekar and
Shivanandappa, 2010). Using natural insecticides can help in controlling many pests and
39 diseases, reduce desertification, and deforestation (Obeng-Ofori, 2010). The challenges with the use of commercially formulated botanicals are that they are costlier compared to synthetic insecticides, and scarce to find. Most botanicals lack data on their efficacy and toxicity.
1.5.7. Life Cycle Assessment (LCA) and Techno-Economic Analysis (TEA) of Crop Agriculture and Grain Treatment
LCA is a tool used to assess the environmental footprint of a product’s lifespan
(Guinee et al., 2002). Impacts of climate change, ecotoxicity, a product or process, waste, etc. can all be assessed using LCA (Roy et al., 2009; Walker et al., 2011). Per ISO 14040 standard, the main purposes of LCA are for improving processing and production, environmental performance assessment, and to make decisions (Tillman, 2000). The IPCC indicated that 14% of the total non-CO2 emissions are associated with agriculture (Li et al.,
2010). In 2005, the soil was the main source of GHS in the form of N2O in three large continents and can be attributed to the high application of manures and nitrogen fertilizers in the soils (EPA, 2006; IPCC, 2007). The majority of fossil fuels’ CO2 emissions are anthropogenic and estimated to (10-15%). Initially, however, more substantial uncertainties surrounded CO2 emissions associated with agriculture which was estimated to be between 10% and 150% (IPCC, 2006).
Biomass burning and forestry could be a major contributing factor. In 2005, agriculture recorded between 5.1 and 6.1 Gt CO2 eq./yr GHG emissions, and forestry and land use activities like forest degradation, fires caused by peat, and drainage recorded 7.5-
-1 8.5 Gt CO2 eq.yr (IPCC, 2005). Agriculture contributed one-third to the average human-
-1 activity related GHGs of about 50 Gt CO2 eq.yr that year (Smith et al., 2007). Carbon dioxide equivalent emissions from croplands’ fossil fuel usage were estimated to be
40
-1 between 0.4 and 0.6 Gt CO2 eq.yr in 2010 (IPCC, 2014). The highest total annual emission from agriculture was recorded in 2011 (5,335 Mt CO2 eq.), and almost 9% higher than the average from 2001-2010 (Tubiello et al., 2014). From 2001 to 2011, global annual emissions increased by 14% (4,684 to 5,335 Mt CO2 eq.) in many developing countries including Ghana. But in developed countries like the US, there was a decrease of -3%.
Within 2001-2011, the largest contributors to global emissions on continent basis were
Asia (44%), the Americas (26%), Africa (15%) and Europe (12%) (Tubiello et al., 2014).
In 2011, the annual total worldwide emissions linked to the use of fertilizers was
725 Mt CO2 eq., equaling around 14% of the entire agricultural emissions in that year. The emissions in non-Annex I countries which include Ghana was more than 70% of the total.
Sixty-three percent, 20%, 13%, and 3% were the emissions contributed respectively by
Asia, Americas, Europe and Africa (Tubiello et al., 2014). It is estimated that global fertilizer emissions could increase by 32% in 2030, and 48% in 2050, and it is supposed to reach almost 900 Mt CO2 eq. in 2050. More than 480 million tons of GHG emissions to the atmosphere each year come from synthetic fertilizers and pesticides production, although annual emissions from pesticides production are comparatively low (between
0.003 and 0.14 Pg CO2 eq.) (Bellarby et al., 2008). Estimates of carbon emission for production, transportation, storage and transfer of insecticides was estimated to be between
-1 1.2 and 8.1 kg CO2 eq.kg (Pimentel, 1980). West and Marland (2002) estimated 4.6 kg
-1 CO2 eq.kg for production, packaging, and transport of insecticides. Estimated CO2 emission from the production of insecticides was reported to be between 1.2-11.9 kg CO2 eq.kg-1 (Lal, 2004).
41
Greenhouse gas data show that emissions over the past 50 years from agriculture, forestry, and fisheries almost doubled and expected to cause 30% rise by the year 2050 if actions for reductions are not made (FAO, 2014b). The FAO concerning 2001-2010 emissions has projected worldwide agricultural emissions to rise respectively in 2030 and
2050 by 18% and 30% and to reach emissions greater than 6,300 Mt CO2 eq. in 2050.
Similarly, N2O emission is estimated to have 50% rise by 2020 (relative to 1990) (Mosier and Kroeze, 2000; EPA, 2006). In 2014, agriculture emission in the US was 9% (fig. 1.14), which was the lowest compared to the other sectors (EPA, 2016).
The application of treatment to grains before storage involves the use of income.
Whether the insecticide to be used is synthetics or natural involves cost. The costs and environmental impacts of both types of insecticides are not the same, although their potency could be the same depending on the active ingredients and target insects. Synthetic insecticides are known to be less costly but have a high negative environmental impact which is vice versa to the use of natural insecticides concerning cost and environmental impact. In recent times, the use of actellic super which contains pirimiphos-methyl (1.6%) and permethrin (0.3%) is common in Ghana and most African countries, and this chemical has proven to be potent against many grains storage insects.
Majority of farmers (80% to 90%) in Ghana use synthetic pesticides in crop management against insects and diseases (NPAS, 2012). Farmers in Africa uses about 4% of the pesticides in the world. The purchase of pesticides is a financial constraint to farmers
(NPAS, 2012). On average farmers spends around 600 cedis a year per acre on chemical fertilizer and pesticide, and probably 200 cedis on pesticides (NPAS, 2012). Due to low labor cost and availability of plant material in developing nations, simple botanical
42 insecticides can be developed for farmers (Leatemia, 2003). Similarly, Amoabeng et al.
(2014) indicated that the available inexpensive plant's species could be used to control insects rather than synthetic insecticides, and farmers won’t be financially constraint.
Complete dependence on pesticides is unsustainable, and we also cannot escape the environmental and health implications. A socio-economic assessment in Mali reported a substantial increase in pesticide imports decades ago which was about US$10 million in cost annually. Mistakenly, we are concerned about avoiding yield losses without considering the cost-effectiveness of the method used (Fleischer et al., 1999).
Techno-economic assessment (TEA) in principle is a cost-benefit comparison using different methods. The TEA when used comes out with the better insecticide affordable by farmers regarding cost, and the LCA comes out with the better insecticides regarding environmental impact. A trade-off should be reached regarding which insecticide to be used to have a sustainable environment (world).
1.6. Deterioration of Stored Grain: A Review
1.6.1. Factors that Affect Grain Storage
The quality of grain concerning biochemical activities, loss in dry matter, allowable storage time and the entire management of stored grain is affected by temperature and grain moisture content (Lawrence and Maier, 2010). Moisture has immense effects on biological and biochemical activities of grain in storage. Therefore, the moisture of grain and surrounding air has to be controlled and reduced (Jayas and White, 2003). Moisture of grains increases due to the respiratory activities of the grains, molds, and insects. The heat and water vapor produced a result in further grain deterioration (Freer et al., 1990). RH of storage air affects stored grain moisture as grains are hygroscopic and exchange moisture
43 with the surrounding air. Increase in temperature and RH enhance the growth of molds that result in nutrient losses of grain (Shah et al., 2002).
1.6.2. Grain Respiration and Loss in Dry Matter
Increase in grain MC increases respiration rate, hence, to safely store grain, grain and surrounding air moisture should be well managed (Hayma, 2003). The end products of grain respiration (CO2, moisture, and heat) increase storage temperature and loss of grain dry matter (Lee, 1999).
1.6.3. Activities of Molds or Fungi, Insects, and Pests in Grain Deterioration
Mold and fungi contamination is a serious safety problem in tropical regions
(Kaaya and Kyamuhangire, 2006). Storage fungi require grain MC in equilibrium with
70% to 90% RH to invade grain (Reed et al., 2007). Moisture content and temperature importantly influence the molds or fungi growth (Alborch et al., 2011). Mold infestation results in grain discoloration, loss of dry matter, changes in stored reserves, and loss in quality (Chuck-Hernández et al., 2012). Storage fungi could cause at least 50% of maize grain losses in tropical countries (Fandohan et al., 2003). Grain damage and cracking expose grain to fungal growth and surviving (Fandohan et al., 2006).
Globally, losses that occur in stored grains are caused by insect infestations. In tropical countries, S. zeamais is the major pest of maize grain (Kanyamasoro et al., 2012).
According to Hellevang (2005), maize allowable storage time is the time of reaching grain dry matter decomposition of 0.5%. The loss in corn dry matter is critically related to the
1 CO2 produced. About 7.33g of CO2 kg- of dry matter is needed to lose 0.5% of dry matter
(Bern et al., 2002).
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Figures
Agro-based Meat 50% industry < 30% Cereals 51%
Fish 60%
Cereals Fish Meat Agro-based industry
Figure 1.1. Percentage of the Various Sectors of Agriculture Production in Ghana (MoFA, 2007).
Maize grain Rice grain Sorghum grain Millet grain Wheat grain
Figure 1.2. The Five Major Grains Cultivated in Ghana.
64
Figure 1.3. The Agro-ecological Zones in Ghana (FAO 2005 (Modified), RESPA 2008).
65
Figure 1.4. Different Platforms for Maize Drying in Africa (Hodges, 2001).
Figure 1.5. On-Ground Drying of Maize Grains in Africa (World Bank, 2011).
66
Figure 1.6. Mud Silos for Maize Storage in Nigeria (GKI, 2014 credited to IITA).
Figure 1.7. Different kinds of Metal Silos for Maize Storage (CGIAR, 2013).
67
Figure 1.8. Purdue Improved Crop Storage (PICS) Bags for Grain Storage (FoodTrade, 2017).
Figure 1.9. PIDS Technology (Ileleji, 2012, PIDS-I Prototype) for Drying Grains.
68
Figure 1.10. Shucking and Shelling Corn in Rural Ghana (MIT, 2015).
Figure 1.11. Different Types of Local Maize Shellers Used in Ghana (MIT, 2015).
69
Energy In: Electricity Mass In: water, chemical auxiliaries, auxilliary media Recycling of Catalyst
Truck, Gasoline
Chemical Operation/Process/ Packaging & Active Chemical Raw material Bought Products Reactions & Unit Operations Transport
CO2, NOx
Mass out: Waste water, solid waste, gas waste, Energy out: Hheat
Byproduct & Non-reacted raw materials
Figure 1.12. Unit Operations of Chemical Synthesis (Insecticides), and Energy and Mass Flows (in & out).
70
Plant material Raw Materials Harvested Manual Harvest, CO2
Tracks, Gasoline Raw Materials Transported CO2, CO & NOx
Water Raw Materials Cleaned and Graded Waste Water
Electricity Raw Materials Weighed and Put into Vessel
Electricity, water Steam Distillation Heat, water vapor
Collection in a Filter Jar
Electricity Oil Separated from Water Hydrosol
Essential Oil Heat, Water vapor, water,
Electricity, chemicals, packaging material Quality Control & Packaging
Gasoline, truck Transportation & Marketing CO2, NOx
Figure 1.13. Flow Chart for Essential Oil Production, and Material and Energy Flows.
71
Figure 1.14. US Green House Emission in 2014 (EPA, 2016).
72
Table
Table 1.1. Estimated Ghana’s Maize Market Composition (Gage et al., 2012).
Quantity Percentage of Percentage of (Mg) Total Consumption Marketed Maize 1,785,000 Total maize consumption
801,000 45 Subsistence consumption by the producer. Households & post-harvest losses
410,000 23 42 Animal feed market (largely poultry)
328,000 18 33 Human consumption (informally traded)
246,000 14 25 Formally traded for processing (industrial & processed food)
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CHAPTER 2. RESEARCH PROBLEM, JUSTIFICATION, OBJECTIVES, AND HYPOTHESES
2.1. Research Problem
Farmers face challenges of Sitophilus zeamais during the storage of maize seeds and grains (previous study). Some of these farmers apply synthetic chemicals which are although effective against S. zeamais, they also complained about the inappropriate (misuse or misapply) use of these chemicals by their colleagues. This exposes farmers that use these synthetic chemicals and consumers to health risks, and there is also environmental footprint concern. Therefore, there is a need for alternative methods for storing seeds and grains that could eliminate the use of synthetic insecticides in Ghana, and concurrently enhance farmers finance.
2.2. Research Justification
Harvested grains are highly susceptible to deterioration even if they have previously not been infected in the field. Various techniques are employed to protect grains from PHL which results in economic losses due to the reduction in grain quality and quantity from the possible attacks by insect, diseases, rodents, and pathogenic microorganisms (Kader,
2005; Zorya et al., 2011; Tefera, 2012). The damage caused by Sitophilus zeamais to stored grains in Sub-Saharan regions is enormous and has been a threat to food security for decades. Mihale et al. (2009) reported that in developing countries insects can cause grain pre-harvest and post-harvest losses of 15% to 100% and 10% to 60% respectively. Efforts to control grain infestation for decades are unprecedented. Mechanical or physical techniques (Banks, 1987; Paliwal et al., 1999; Bbosa et al., 2014; Suleiman et al., 2015), chemical treatments (Cogburn et al., 1975; Brattsten et al., 1986; Collins et al., 2000;
Pourmirza, 2006); gamma irradiation (Brown et al., 1972; Darfour et al., 2012); and
74 hermetic treatments (Bern et al., 2013; Murdock and Baoua, 2014) are all practiced to control infestation and damage of grains by stored product insects.
However, the most predominant treatment method used is the synthetic chemical treatment, and it is very effective (Brattsten et al., 1986; Collins et al., 2000; Pourmirza,
2006) when the right dose is used. The excessive use of synthetic chemicals has many environmental and health detrimental impacts (Markowitz, 1992; Gupta et al., 2001; Hurtig et al., 2003). Insect pests are also becoming resistant to pesticides (Mahmud et al., 2002), and there is an increasing cost to the environment and society (Pimentel et al., 1980).
Carbon emissions associated with the manufacturing, transport, and storage of insecticides
-1 was estimated to be between 1.2 and 11.9 kg CO2 eq.kg (Pimentel, 1980; West and
Marland, 2002; Lal, 2004). Most synthetic chemicals are becoming less effective against storage product insects. For example, Phosphine, a synthetic compound predominantly used in Ghana has been reported in Australia and India to be less effective against insects
(Leelaja et al., 2007).
Besides these general and global challenges linked to synthetic chemical usage, first, farmers in Ghana are faced with the possibility of buying adulterated synthetic chemicals from unscrupulous traders (Stevenson et al., 2014). Second, synthetic chemicals may not be readily available in most rural markets for purchase. Third, farmers and consumers face health dangers associated with misapplication and excessive use of synthetic chemicals. According to the study by NPAS (2012), over 25% of farmers suffered from the direct inhalation of chemicals, and 20% of farmers suffered from spillover from chemicals. Fourth, the cost of treatment could be unbearable to farmers most especially if
75 they have to use environmentally friendly chemicals like botanicals. Leatemia (2003) reported that farmers that use botanical insecticide which is safe get less economic benefits.
Other investigators have proven that the application of physical control methods is simple, affordable, safe, and efficient against insects’ pests (Facknath, 1993; White et al.,
1997; Suleiman et al., 2016). Although botanical insecticides are friendly and effective to use, they are expensive (Obeng-Ofori, 2010) and rare in developing nations. Since the life of a seed mostly depends on its MC, controlling seed MC in storage is very important due to the influence on seed viability. The use of zeolite beads is efficient to dry seeds safely
(UC Davis, 2009). Zeolite beads work efficiently by forming microcrystalline pore structures that bind water specifically and tightly (Hay et al., 2012; Hay and Timple, 2013) until equilibrium is reached. Activated zeolite beads can absorb 20% to 25% of its dry weight in water, it is cheap, safe and efficient (Bradford et al., 2018).
2.3. Research Objectives
The overall research objective was to use non-chemical techniques to control the deterioration of stored grain/seed to improve food security, and financial security of farmers. The specific objectives of the research were:
1. To compare the storability, susceptibility, grain moisture, rate of oxygen depletion, and weight losses in the hermetic and non-hermetic storage of sorghum grains.
2. To perform an environmental impacts assessment and cost analysis on the manufacturing, transport, and usage of actellic super (pirimiphos-methyl and permethrin) and NeemAzal (azadirachtin) for maize grain treatment in Ghana.
3. To assess pre-harvest and postharvest losses encountered by farmers, storage practices, and farmers’ awareness and knowledge of mycotoxin.
76
4. To determine the efficacy of the periodic physical disturbance method on the mortality of S. zeamais, and the possibility to adopt the technology in Ghana.
5. To tests and ascertain the benefits of storing maize grain using hermetic bags (GrainPro bags) against woven polypropylene bags.
6. To evaluate the feasibility of using zeolite beads in storing maize seeds in Ghana, and determine any effects the zeolite beads might have on seed germination and vigor.
7. To evaluate the cost-effectiveness of five different maize grain handling techniques.
2.4. Research Hypotheses
The hypotheses tested were based on the specific objectives assigned to each chapter.
Chapter 3
Ho: A constant RH and different temperatures will not affect sorghum grain
MC, the rate of O2 depletion and CO2 accumulation, the susceptibility of
organic and conventional sorghum grains to S. zeamais, and S. zeamais
mortality in hermetic and non-hermetic storage.
Ha: A constant RH and different temperatures will affect sorghum grain
MC, the rate of O2 depletion and CO2 accumulation, and susceptibility of
organic and conventional sorghum grains to S. zeamais, and S. zeamais
mortality in hermetic and non-hermetic storage.
Chapter 4
Ho: There is no difference in global warming potential, ecotoxicity and
human health impacts, and treatment cost between the manufacturing, transport,
77
and usage of actellic super (pirimiphos-methyl and permethrin) and NeemAzal
(azadirachtin) in treating maize grain in Ghana.
Ha: There is a difference in global warming potential, ecotoxicity and
human health impacts, and treatment cost between the manufacturing, transport,
and usage of actellic super (pirimiphos-methyl and permethrin) and NeemAzal
(azadirachtin) in treating maize grain in Ghana.
Chapter 5
No hypothesis because descriptive statistics were used.
Chapter 6
Ho: Periodic physical disturbance will not cause adult S. zeamais mortality
during storage of maize grains.
Ha: Periodic physical disturbance will cause adult S. zeamais mortality
during storage of maize grains.
Chapter 7
Ho: Hermetic bags (GrainPro bags) will not effectively store maize grain
better than woven polypropylene bags.
Ha: Hermetic bags (GrainPro bags) will effectively store maize grain better
than woven polypropylene bags.
Chapter 8
Ho: The zeolite beads will not effectively reduce seeds MC during storage.
Ha: The zeolite beads will effectively reduce seeds MC during storage.
Ho: The zeolite beads will not affect seed germination and vigor after
storage.
78
Ha: The zeolite beads will affect seed germination and vigor after storage.
Chapter 9
Ho: All five grain handling techniques will cost-effectively be the same.
Ha: At least one of the handling techniques will be most cost-effective.
2.5. Dissertation Outline
This dissertation is organized into 10 chapters. Chapter 1 contains a general introduction and literature review. Chapter 2 includes the research problem, justification, objectives, hypotheses, and dissertation outline. Chapter 3 through 9 are the articles in the format of Applied Engineering in Agriculture for subsequent submission. Chapter 3 focuses on the storability of organic and conventional sorghum grains at a constant RH and different temperatures. Secondly, the susceptibility of the sorghum grains to S. zeamais, and rate of depletion or accumulation of oxygen and carbon dioxide when sorghum grains are stored hermetically was determined. Chapter 4 focuses on the environmental impacts assessment and cost analysis of the manufacturing, transport, and use of actellic super and
NeemAzal insecticides in the treatment of maize grains in Ghana. Chapter 5 looks at the experiences of farmers in five maize-grown regions in Ghana regarding pre-harvest and post-harvest practices, and farmer’s knowledge of mycotoxins contaminations. Chapter 6 looks at the efficacy and adoptability of the periodic physical disturbance method to control adult S. zeamais in Ghana. Chapter 7 focuses on the efficacy of hermetic storage bags over woven polypropylene bags during maize grain storage in Ghana. Chapter 8 looks at the effectiveness of safely storing seeds with zeolite beads irrespective of the seed MC. Any possible effect of zeolite beads on seed germination (viability) and vigor was determined.
Chapter 9 looks at the possibility of farmers forming cooperatives to have the capability to
79 use modern technology of handling grain. Current technologies maintain grain quality and quantity with minimal losses, and this increases farmers’ sales and profits. The cost- effectiveness of five modern and conventional techniques were analyzed in this chapter.
Lastly, chapter 10 contains the general conclusions, recommendations, and recommended future research work based on the various chapters and the research outcomes.
2.6. References
Banks, H. J. (1987). Impacts, physical removal and exclusion for insect control in stored products. In: E. Donahaye & S. Navarro (Ed.), Stored-Product Protection. Proc. 4th Intl. Working Conf., pp. 165-184. Maor-Wallach Press, Caspit, Jerusalem,
Bbosa, D., Brumm, T. J., Bern, C. J., & Rosentrater, K. A. (2014). Evaluation of hermetic maize storage for smallholder farmers. Proceedings and presentations of ICABBBE 16th International Conference on Agricultural and Biosystems Engineering Conference, 29-30 September 2014, Los Angeles, United States of America, paper 380.
Bern, C. J., Yakubu, A., Brumm, T. J., & Rosentrater, K. A. (2013). Hermetic storage systems for maize stored on subsistence farms. In: ASABE Annual International Meeting. Paper number: 131591815, St. Joseph, MI: ASABE.
Bradford, K. J., Dahal, P., Asbrouk, J. V., Kunusoth, K., Bello, P., Thompson, J., & Wu, F. (2018). The dry chain: Reducing postharvest losses and improving food safety in humid climates. Trends in Food Science and Technology, 71, 84-93.
Brattsten, L. B., Holyoke, C. W., Leeper, J. R., Affa, K. F. (1986). Insecticide resistance: Challenge to pest management and basic research. Science, 231, 1125-1160.
Brown, G. A., Brower, J. H., & Tilton, E. W. (1972). Gamma radiation effects on Sitophilus zeamais and S. granarius. Journal of Economic Entomology, 65, 203-205.
Cogburn, R., Simonaitis, R., & Richard, A. (1975). Dichlorvos for control of stored- product insects in port warehouses: Low-volume aerosols and commodity residues. Journal of Economic Entomology, 68, 361-365.
Collins, P. J., Nayak, M. K., & Kopittke, R. (2000). Residual efficacy of four organophosphate insecticides on concrete and galvanized steel surfaces against three Liposcelid psocid species (Psocoptera: Liposcelidae) infesting stored products. Journal of Economic Entomology, 93, 1357-1363.
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Darfour, B., Ocloo, F. C. K., & Wilson, D. D. (2012). Effects of irradiation on the cowpea weevil (Callosobruchus maculates F.) and moisture sorption isotherm of cowpea seed (Vigna unguiculata L. Walp). Arthropods, 1, 24-34.
Facknath, S. (1993). Effect of grain tumbling on infestation by some insect pests. Revue Agricole et sucrière de l'Ile Maurice, 72, 5-8.
Gupta, A., Upadhyay, R. K., & Saxena, P. N. (2001). Toxicity evaluation of certain blood biochemical parameters in Passer domesticus (Linn.). Journal of Scientific and Industrial Research, 60, 668-674.
Hay, F. R., Thavong, P., Taridno, P., & Timple, S. (2012). Evaluation of zeolite seed ‘Drying Beads®’ for drying rice seeds to low moisture content prior to long-term storage. Seed Sci. & Technol., 40, 374-395.
Hay, F. R., & Timple, S. (2013). Optimum ratios of zeolite seed Drying Beads® to dry rice seeds for genebank storage. Seed Sci. & Technol., 41(3), 407-419.
Hurtig, A. K., San Sebastián, M., Soto, A., Shingre, A., Zambrano, D., & Guerrero, W. (2003). Pesticide use among farmers in the Amazon basin of Ecuador. Arch Environ Health, 58, 223-228.
Kader, A. A. (2005). Increasing food availability by reducing postharvest losses of fresh produce. In International postharvest symposium 682 (pp. 2169-2176). Available online at http://ucce.ucdavis.edu/files/datastore/234-528.pdf. Retrieved on 30 July 2016.
Lal, R. (2004). Carbon emission from farm operations. Environment International, 30, 981-990.
Leatemia, J. A. (2003). Development of a botanical insecticide from Ambon and surrounding areas (Indonesia) for local use. Ph.D. thesis. The University of British Columbia.
Leelaja, B. C., Rajashekar, Y., Vanitha, P., Begum, K., & Rajendran, S. (2007). Enhanced fumigant toxicity of allyl acetate to stored-product beetles in the presence of carbon dioxide. Journal of Stored Products Research, 43(1), 45-48.
Mahmud, M. K., Khan, M. M. H., Husain, M., Alam, M. I., & Afrad, M. S. I. (2002). Toxic effects of different plant oils on pulse beetle Callosobruchus chinensis Linn. (Coleoptera: Bruchidae). J. Asiat. Soc. Bangladesh, Sci., 28(1), 11-18.
Markowitz, S. B. (1992). Poisoning of an urban family due to misapplication of household organophosphate and carbamate pesticides. Clinical Toxicology, 32, 295-300.
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Mihale, M. J., Deng, A. L., Selemani, H. O., Kamatenesi, M. M., Kidukuli, A. W., & Ogendo, J. O. (2009). Use of indigenous knowledge in the management of field and storage pests around Lake Victoria basin in Tanzania. African Journal of Environmental Science and Technology, 3(9), 251-259.
Murdock, L. L., & Baoua, I. B. (2014). On Purdue improved cowpea storage (PICS) technology: Background, mode of action, future prospects. J. Stored Prod. Res., 58, 3-11.
NPAS. (2012). Northern Presbyterian agricultural services. Ghana’s pesticide crisis: The need for further government action, April 2012, pp. 2-50.
Obeng-Ofori, D. (2010). Residual insecticides, inert dust, and botanicals for the protection of durable stored products against pest infestation in developing countries. In Stored Products Protection, M.O. Carvalho, P. G. Fields, C. S. Adler et al., Eds., Proceedings of the 10th International Working Conference on Stored-Product Protection, pp. 774-788, Julius-K¨uhn-Archiv 425.
Paliwal, J., Jayas, D. S., White, N. D. G., & Muir, W.E. (1999). Effect of pneumatic conveying of wheat on mortality of insects. Applied Engineering in Agriculture, 15, 65-68.
Pimentel, D., Andow, D., Dyson-Hudson, R., Gallahan, D., Jacobson, S., Irish, M.…Vinzant, B. (1980). Environmental and social costs of pesticides: A preliminary assessment. Oikos, 34, 125-140.
Pourmirza, A. A. (2006). Effect of acorlien vapors on stored-radiation sensitivity and damage in phosphine-resistance and susceptible strains of Rhyzopertha dominica. Journal of Economic Entomology, 99, 1912-1919.
Rajashekar, Y., Reddy, P. V., Begum, K., Leelaja, B. C., & Rajendran, S. (2006). Studies on aluminum phosphide tablet formulation. Pestology, 30(4), 41-45.
Stevenson, P. C., Arnold, S. E. J., & Belmain, S. R. (2014). Pesticidal plants for stored product pests on small-holder farms in Africa. In D. Singh (Ed.), Advances in Plant Biopesticides (pp. 149-172). Retrieved from http://www.bbc.co.uk/news/world- asia-india-23436348.
Suleiman, R., Rosentrater, K. A., & Bernard, C. (2016). Periodic physical disturbance: An alternative method to control Sitophilus zeamais, the maize weevil infestation. Ph.D. diss. Ames, Iowa State: Iowa State University of Science and Technology, Department of Agricultural and Biosystems Engineering.
Suleiman, R., Rosentrater, K. A., & Bern, C. (2016). Postharvest practices and mycotoxins of maize in three agro-ecological zones in Tanzania. Ph.D. diss. Ames, Iowa State: Iowa State University, Department of Agricultural and Biosystems Engineering.
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Tefera, T. (2012). Post-harvest losses in African maize in the face of increasing food shortage. Food Security, 4(2), 267-277.
UC Davis. (2009). New technology for postharvest drying and storage of horticultural seeds. www.hortcrsp.ucdavis.edu/main/4seeds.html (Retrieved 5 September 2018).
West, T. O., & Marland, G. A. (2002). Synthesis of carbon sequestration, carbon emissions, and net carbon flux in agriculture: Comparing tillage practices in the United States. Agriculture, Ecosystems & Environment, 91, 217-232.
White, N. D., Jayas, D. S., & Demianyk, C. J. (1997). Movement of grain to control stored- product insects and mites. Phytoprotection, 78, 75-84.
Zorya, S., Morgan, N., & Rios, L. D. (2011). Missing food: The case of postharvest grain losses in Sub-Saharan Africa. The international bank for reconstruction and development/ The World Bank. Report No. 60371-AFR. The World Bank, Washington, DC.
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CHAPTER 3. STORABILITY OF ORGANIC AND CONVENTIONAL SORGHUM GRAINS AT CONSTANT RELATIVE HUMIDITY, AND VARIED TEMPERATURES
Modified from a manuscript to be submitted to the Applied Engineering in Agriculture
Abstract
Sorghum (Sorghum bicolor L. Moench) is an ancient cereal grain. Sitophilus zeamais is an insect, and it is considered a major damaging pest of grains. The aim of the study was to compare the storability of organic and conventional sorghum grains at constant RH and different temperatures. Susceptibility of the two grain types to S. zeamais, grain moisture, and the rate of changes in O2 and CO2 concentrations in airtight jars were similarly studied. Two replicates of each type of grain, three temperature conditions (15oC,
20oC, and 30oC), relative humidity of 75%, and three storage periods (0, 15, and 30 days) were used in a completely randomized design. The experiment was done in an environmental chamber. Daily oxygen (O2), and carbon dioxide (CO2) concentrations were measured in the hermetic jars using oxygen meter. The percent mortality of S. zeamais was determined on the 15th day (hermetic), and the 15th and 30th days (non-hermetic), and also the percentage loss in grain weight was determined on day 30. In the hermetic jars that contained S. zeamais, O2 depleted from 21% to 7.6%, but O2 concentration almost remained constant in the control. Carbon dioxide concentration increased from 0.03% to
11.1%. High concentrations of CO2 and low concentrations of O2 were observed as the temperature was increased. The changes in CO2 and O2 concentrations might have resulted in the 100% S. zeamais mortality in the hermetic jars. The loss in grain weight increased with increased temperatures and worsened in conventional grains. At 30oC and 30 days in the non-hermetic jars, only one new S. zeamais emerged from the conventional grains. The
84 conventional grain was more susceptible to changes in storage conditions and damage by
S. zeamais. Importantly, the quality and quantity of sorghum grain stored in airtight containers were maintained, especially when stored at low temperatures compared to high temperatures.
Keywords: Sorghum; relative humidity; temperature; oxygen and carbon dioxide; mortality of insects.
3.1. Introduction
Sorghum (Sorghum bicolor L. Moench) is an ancient cereal grain and thought to have originated over 8,000 years ago in Northern Africa. Sitophilus zeamais is an insect, and it is considered a major damaging pest of grains. According to FAO (2016), World cereal production in 2016 was anticipated to fall short of the projected demand in 2016/17 slightly. World sorghum production in 2016/2017 has been estimated by the USDA to be
63.99x106 Mg slightly above 2015/2016 estimate which was 60.86x106 Mg. The estimated
63.99x106 Mg for 2016/2017 could represent a worldwide increase of 3.13x106 Mg or
5.14% in sorghum production. The USDA (2016) also estimated the US and Ghana to produce sorghum of about 10,338,000 Mg and 300,000 Mg in 2016/2017, respectively.
There has been double-digit growth in consumer demand for organically produced goods since the 1990s (USDA, 2015).
To store sorghum grain safely for many months, it should be dried to low moisture of around 12%. However, to maintain grain quality during storage, using S. zeamais resistant sorghum varieties rather than insecticides is essential. Both organic and conventional sorghum grains may have genomes which resist attack by S. zeamais, but the extent of their susceptibility may be different. S. zeamais can damage both corn and sorghum grain. S. zeamais begins grain infestation in the field before harvest. Eggs are
85 further deposited in kernels during storage, and eggs hatch into larvae. Both the adult and larvae feed on the stored grain and cause severe damage to grain. The use of airtight grain storage technique reduces grain damage associated with storage (Moussa et al., 2014).
Hermetic storage eliminates gaseous exchange between stored grain and the external environment. Insects found in airtight bags or jars are denied O2 as the limited O2 is exhausted through respiration. This results in the mortality of insects (Quezada et al., 2006;
Murdock et al., 2012).
Grain in storage deteriorates when its MC changes with varying storage temperature and RH. The quantity of moisture exchanged within grain column, corresponds to temperature and RH of the surrounding air. When the air temperature is increased at constant RH, equilibrium moisture content (EMC) decreases (Sadaka and
Bautista, 2014). High air temperature increases the rate of moisture absorption. MC in equilibrium with 70% RH is reported as safe for grain storage (Pixton and Warburton,
1971). Extensive grain deterioration due to microbial growth occurs at above 75% RH
(Darfour et al., 2012). To limit mold growth during storage, 75% RH and grain MC of less than 10% were used. Many storage studies have been conducted on large-sized grains like corn, and there are limited storage studies on small-sized grains like sorghum. This necessitated the current storage study as small-sized grains are important for food security.
The aim of the study was to compare the storability of organic and conventional sorghum grains at constant RH and different temperatures. Susceptibility of the two grain types to
S. zeamais, grain moisture, and rate of changes in O2 and CO2 concentrations in airtight jars were similarly studied.
86
3.2. Materials and Methods
3.2.1. Experimental design
The conventional and organic sorghum grains used in this experiment were purchased from Nu World Foods Inc., U.S.A. The conventional grain was cultivated using conventional practices while the organic grain was cultivated using organic practices. Two replicates of each type of grain, three temperature conditions (15oC, 20oC, and 30oC), RH of 75%, and three storage times (0, 15, and 30 days) were used in a completely randomized block design (temperature was used as the block). The experiment was done in a Forma
Environmental chamber (Model 3940 series, Thermal Scientific Inc. Marietta, OH 45750).
The temperature values were selected to depict temperature range that occurs in Ghana.
Sitophilus zeamais were obtained from stock in the ABE Department at Iowa State
University.
3.2.2. Moisture content (MC) of grain
ASAE S352.2 (ASAE, 2001) was used to determine the MC of sorghum grain. Ten grams of the samples were measured in triplicates into an oven at 130ºC for 18 h. The initial MC was determined on the first day of the experiment, and the final MC was determined on 15th and 30th days of grain storage.
3.2.3. Hermetic storage studies
The 125 mL glass jars were loaded with 30 g each of sorghum grain type, and 15 adult S. zeamais were placed into each jar. The control and treatment jars were sealed using
Dow Corning high vacuum grease to ensure full air-tight. All the jars were stored inside
o o o the environmental chamber at 15 C, 20 C, and 30 C, and 75% RH. Daily O2 and CO2 concentrations were measured from 1st day to 15th day through a septum using an oxygen
87 meter (CheckPoint II handheld gas analyzer, Dansensor A/S, a Mocon Company, DK-4100
Ringsted, Denmark). Mortality of S. zeamais and MC (%) were determined at 15 days.
3.2.4. Non-hermetic storage studies
About 80 g of each sorghum grain type and 15 adult S. zeamais were loaded into a
246 mL glass jars which had screened lids for air exchange. All jars were stored in the same chamber as the hermetic jars at 15oC, 20oC, and 30oC, and 75% RH. Percent mortality of S. zeamais and grain weight loss were determined on 15 and 30 days. In determining the loss in grain weight, kernels were visually inspected, and the damaged and undamaged kernels were counted, weighed, and recorded. Kernels with characteristic visible holes caused by S. zeamais were considered damaged. The percentage loss in grain weight was determined using Adams and Schulten (1978) equation:
(Wu∗Nd) – (Wd∗Nu) Weight loss (%) = ∗ 100 ……………………………………... (3.1) (Wu)∗(Nd+Nu)
Where Wu= Weight of undamaged kernel, Nu= Number of undamaged kernel, Wd=
Weight of damaged kernel, and Nd= Number of damaged kernel.
3.2.5. Data collection and analysis
The experiment was conducted as follows: At 15oC and 75% RH, 20oC and 75%
RH, and 30oC and 75% RH. The data were analyzed using ANOVA, and means that were significantly different were separated using Tukey-Kramer HSD. The O2 and CO2 concentrations data were graphed using excel.
3.3. Results and Discussion
3.3.1. MC of grains in hermetic jars
At 15oC (table 3.1), MC remained the same for conventional and organic grains stored with or without S. zeamais. At 20oC (table 3.2), MC of conventional grain stored
88 with or without S. zeamais increased in MC with increased storage days, while MC of organic grain remained the same. At 30oC (table 3.3), MC of both conventional and organic grains stored with or without S. zeamais increased with increased days of storage.
The atmospheric changes inside airtight jars are due to respiratory activities of live organisms (grains, insects, and fungi) within the jars. Oxygen level in airtight containers reduces as respiration and metabolism increase, and end products of respiration also increase (Annis, 1990; Banks, 1981). Water vapor is an end product of respiration
(oxidation), and therefore the increase in grain MC at 20oC and 30oC might be the reason.
Thus, the hygroscopic low moisture grain might have absorbed the water vapor released from respiration. The grain MC at 15oC was stable, but the increased grain MC at 20oC and
30oC might be attributed to the increased temperature. An increase in temperature increases the rate of respiration and metabolism (Bewley et al., 2013). According to Bailey (1981), different cereal varieties have different respiration rates. The rate of grain respiration depends on grain major components such as starch and protein (Bewley et al., 2013). The increase in grain MC in hermetic jars can lead to grain deterioration. High grain moisture may be sufficient to activate lipoxygenase enzymes to initiate lipid peroxidation
(deterioration). Lipid peroxidation is likely initiated at MC above 14% (Malik and Jyoti,
2013). When deterioration increases, grain quality and quantity tend to reduce, and food security and income of farmers reduce. In a similar study, Reuss et al. (1994) revealed increased MC of wheat grain as hermetic storage temperature was increased. It is therefore essential to store low MC sorghum grain at low temperatures and RH even if hermetic storage is used. This is to reduce respiration and metabolism that subsequently reduce or maintain stored grain MC. No visible molds were seen, and grain MC was not significantly
89 affected, irrespective of the presence or absence of S. zeamais. The high mortality of S. zeamais during the early stages of storage might be the reason for the significantly low grain MC even though grain was stored with S. zeamais.
3.3.2. MC of grains in non-hermetic jars
At 15oC (table 3.1), MC of both conventional and organic grains increased with days. On day 30, both grain types stored with or without S. zeamais had the highest MC.
Similarly, at 20oC (table 3.2), MC of both the conventional and organic grains increased with days. However, there was no significant difference in MC at 15 and 30 days. The increase in grain MC was expected because the moisture of non-hermetically stored grain is affected by temperature and moisture (RH) of air. The moisture of the sorghum grain might have equilibrated with the surrounding air moisture, and therefore the increased in the grain MC. At 75% RH, the grain might have absorbed moisture from the air which resulted in increased grain MC. This is because grains are hygroscopic, and the grain used had low initial MC. As explained by Bern et al. (2011), during storage when the air temperature is increased at fixed RH, moisture migration between grain and surrounding air increases. Therefore, grain with low initial MC stored under high temperature and RH records increased MC. The MC obtained in this study were between 13.77% and 16.65% at the three different temperatures. The increase in grain MC, especially as the temperature was increased can be attributed to moisture migration from the surrounding air to the low moisture hygroscopic grain. It is therefore prudent to store low MC sorghum grain at low temperatures and RH in non-hermetic conditions to prevent moisture migration from surrounding air to grain. Increase in grain MC can cause grain deterioration and losses, and may increase food insecurity and poverty levels of farmers. The findings closely compare
90 to sorghum grain MC data of 14.1% to 15.7% at 15oC, 13.9% to 15.5% at 20oC, and 13.6% to 15.2% at 30oC (Sadaka et al., 2015).
3.3.3. Percent mortality of S. zeamais
In the non-hermetic jars, percent mortality of S. zeamais was between 3.33% and
16.67%, and 6.67% and 23.33% at 15oC and 30oC, respectively. However, percent mortality of S. zeamais was high at 20oC (33.33% to 86.67%) in the conventional and organic grains. Generally, S. zeamais mortality was between 3.33% and 86.67% in non- hermetic jars, and 100% in hermetic jars. At all three temperatures, 100% S. zeamais mortality was recorded in the hermetic jars (table 3.4). This was not surprising since similar findings from other hermetic storage experiments have been reported (Bern et al., 2011;
Yakubu et al., 2011; Murdock et al., 2012). The 100% mortality was not achieved on the same day among the three temperature conditions. The 100% mortality was at 7 and 9 days in organic and conventional grains, respectively at 15oC. The 100% mortality was at 5 and
7 days in organic grains and conventional grains, respectively at 20oC. The 100% mortality was at 4 days in organic and conventional grains at 30oC. Since 100% mortality of S. zeamais was not achieved on the same day, airtight containers should not be opened during storage without allowing ample storage days for S. zeamais to demise. The differences in mortality between organic and conventional could be due to several reasons. It could be surmised that S. zeamais were not able to easily access nutrients from the grain’s food reserves, especially in the organic grain. Besides asphyxiation due to reduced O2 level, starvation might also induce insect mortality. For example, in figure 3.1, a few quantities of organic grain compared to conventional grain were observed to have holes created by S. zeamais. The seed coat of the organic grain might have been less accessible to S. zeamais to obtain food for survival. Therefore, the 100% S. zeamais mortality in organic grain at
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15oC and 20oC during the early days of storage might also be attributed to starvation.
Sorghum grains that are less susceptible to S. zeamais should be cultivated if available.
The increased storage temperature hastened the days to achieve 100% mortality of
S. zeamais in hermetic jars. S. zeamais is a cold-blooded organism and therefore has a bodily temperature similar to the surrounding air (Neven, 2000; Palumbo, 2011). Hence, the temperature is likely an important abiotic factor that influences the life and habit of S. zeamais. Temperature compared to other abiotic factors can effectively influence the life of insects (Bale et al., 2002). At 30oC, the 100% S. zeamais mortality at 4 days was probably because of the increased storage temperature. When the temperature is increased, respiratory and metabolic activities of S. zeamais also increase (Neven, 2000; Petzoldt and
Seaman, 2006; Palumbo, 2011) resulting in increased O2 consumption and swift O2 depletion in airtight jars. The depleted O2 in the airtight jars might have subsequently caused the high S. zeamais mortality. Farmers can reduce damage caused by S. zeamais when grain is stored in airtight jars at optimum temperature. Yakubu et al. (2011) reported a 100% mortality of S. zeamais at 6 days (27oC), similar to the findings of this study.
3.3.4. Percentage loss in grain weight in non-hermetic jars
The percentage of losses in grain weight were highest in conventional grain at 20oC and 30oC. But there was no significant difference in loss in grain weight between 15 and
30 days (table 3.4). The loss in grain weight correlated negatively with S. zeamais mortality, but averagely with MC of grains (table 3.5). Insects are poikilothermic, and therefore their behavioral activities such as flight, movement, reproduction, feeding, and oviposition are influenced by changes in temperature (Neven, 2000; Petzoldt and Seaman,
2006; Palumbo, 2011). The metabolic activities of S. zeamais including feeding increase with an optimal increase in temperature, hence the high losses in grain weight at 20oC and
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30oC. Grain storage in non-hermetic jars is therefore appropriate at low temperatures to reduce feeding activities of S. zeamais to have safe storage. The high loss in grain weight in the conventional grain could be associated with inherent genetic differences between the two grain types. The inherent differences could be varietal differences (thus, differences in grain seed coat, stored reserves, maturation, and size) (Bailey, 1940; Bailey, 1981; Jian and
Jayas, 2012; Bewley et al., 2013), differences in planting environment and cultural practices (Nedel, 2003) (e.g. organically or conventionally cultivated), and grain preference by S. zeamais. The quantity of conventional grain infested outnumbered that of organic grain (fig. 3.1). If available, farmers are encouraged to use varietal sorghum seeds resistant to insects (e.g. S. zeamais) attack to minimize PHL. This is critically important in
SSA where average temperature favors S. zeamais survival and growth.
3.3.5. The emergence of new S. zeamais in non-hermetic jars
No S. zeamais emerged from grains at 15oC and 20oC. When storage temperature is low, the rate of mortality, respiration, and reproduction of insects (Sitophilus species) lessen (De Lima, 1990; IRRI, 2006). Farmers can safely store grain at low temperatures as
S. zeamais reproduction or emergence is reduced. However, this favors farmers in temperate regions rather than SSA. This is because in SSA the average temperature is above 20oC, and refrigeration storage is costly to farmers. Only one S. zeamais emerged from conventional grain at 30oC and 30 days. The 30oC storage temperature was within the temperature range for possible development and emergence of new S. zeamais. Growth and development of insects increase between 5°C and 10°C, and 30°C and 35°C (FAO,
1994; IRRI, 2008). Optimally, the development of S. zeamais happens around 27°C
(Arannilewa et al., 2006), and best multiplication at 30ºC and above 65% RH (Villers et al., 2006). The high survival and development rate of S. zeamais in SSA could be ascribed
93 to the existing high temperature and RH which favor S. zeamais. Therefore having low temperature and RH at storage is important to minimize S. zeamais multiplication and PHL.
3.3.6. Depletion of oxygen (O2), the increase in carbon dioxide (CO2), and S. zeamais mortality in hermetic jars
Oxygen concentration was about 21% in jars without S. zeamais at all the three temperatures. But O2 concentration in jars with S. zeamais at all the three temperatures depleted (figures 3.2, 3.3, and 3.4). The rate of O2 depletion was quick in jars that contained conventional grain compared to that of organic grain. Minimum O2 concentration was 7.6% at 4 days in jars that contained conventional grain at 30ºC. Minimum O2 concentration was
15% at 9 days, and 10.05% at 7 days at 15ºC and 20ºC, respectively. Carbon dioxide concentration increased in jars with S. zeamais in both organic and conventional grains.
However, CO2 concentration was maintained in jars without S. zeamais at 15 days (figures
3.5, 3.6, and 3.7). As O2 concentration reduced, CO2 concentration increased in jars with
S. zeamais at all the three temperatures especially as the temperature was increased. The
CO2 concentration was between 0.03% and 11.1% across all the three temperatures.
When temperature increases, respiratory activities of S. zeamais and grains also increase, hence high amount of O2 is consumed and CO2 is produced as an end-product.
Biotic organisms (insects, fungi, and grain) consume O2 in airtight jars through respiration, which increases CO2 concentration (White and Jayas 2003). The respiratory activities of the S. zeamais might have resulted in the decreased O2 concentration and increased CO2 concentration in the hermetic jars with S. zeamais. S. zeamais mortality increased with reducing O2 concentration, and the rapidity of O2 depletion depended on increased temperature. Respiration increases with increased temperature, grain MC, and degree of fungal or insect infestation (Bell and Armitage, 1992). The reduced O2 concentration might
94 have resulted in the 100% mortality of S. zeamais. The rapid attainment of 100% mortality increased with increased temperature. According to Navarro et al. (2007), low O2 concentration and 100% mortality occur within a matter of days to 2-weeks, although mostly a function of grain MC. IRRI (2008) attributed S. oryzae mortality to respiratory activities of rice grain and S. oryzae that reduced O2 concentration from 5% to 10%.
Although S. zeamais was not used in the hermetic study of wheat by Reuss et al. (1994),
O2 concentration decreased (0 to 550 ppm) with increased temperature, and CO2 concentration increased. Navarro (2006) and Navarro et al. (1994) reported that increased temperature and rapid O2 intake by insects in airtight jars increased mortality.
In this study, grain respiration had minimum impact on O2 and CO2 concentrations which could be due to the low initial grain MC. Grain respiration depends also on grain
MC, and respiration is high in damp grains. Respiration increased in damped wheat grain stored at high temperature (White et al., 1982 a). The low initial grain MC might have affected the respiration rate, hence, the final O2 concentration was not below 7% compared to other findings. The O2 concentrations reported in other studies were less than 5%
(Gummert et al., 2004), and 3% (Navarro, 1978; Banks and Annis, 1990; Fleurat, 1990).
Importantly, even at 16% of O2 concentration, 100% S. zeamais mortality was achieved.
These findings contradict the prior assertion that S. zeamais mortality is only achievable at
O2 concentration below 5% or 3% (Navarro, 1978; Banks and Annis, 1990; Fleurat, 1990;
Gummert et al., 2004). The pattern of O2 concentration regarding the increase after an initial decrease was similar to previous findings (Villers et al., 2010; Bbosa et al., 2014).
High concentration of CO2 (>20%) is toxic to many stored-product insects at a suitable temperature (Annis, 1987; Jian and Jayas, 2012). The concentration of CO2 or O2
95
depends on the rate of respiration, grain MC and temperature. However, CO2 in airtight jars can also increase when dead insects decompose (Hyde et al., 1973; Navarro et al.,
1994, 1990). The 100% S. zeamais mortality could also be due to the elevated CO2 concentration. According to White and Jayas (2003), 7.5% to 19.2% of CO2 caused death in many beetles including flat grain beetles. High CO2 concentration maintains the quality of stored grain (White and Jayas, 2003; Banks 1981). Farmers mostly in SSA can control
S. zeamais in grains by reducing O2 concentration or increasing CO2 concentration. Since farmers in SSA do not have the technique to introduce high CO2 concentration or reduce
O2 concentration in stored grain bags, the hermetic technique is most appropriate, easy, affordable, and effective. This is achievable when suitable temperature, airtight jars and sufficient days are employed in the storage of low moisture grains.
Genetic factors, cultural practices adopted (organic or conventional, planting time and density, etc.), and environmental conditions during seed formation can affect the chemical composition of seeds of different species and cultivars of the same species
(Nedel, 2003). Differences in chemical compositions (not considered in this study) might have influenced the feeding preference of S. zeamais, and the stored reserves and rate of respiration of the grains. However, Gindri et al. (2017) observed no differences in the physiological quality of seeds produced from organic and conventional farming systems.
3.4. Conclusions
Grain MC equilibrated with air moisture during storage resulting in increased grain final MC in non-hermetic jars. At 15oC, respiratory and metabolic activities reduced, and hence grain MC was maintained in hermetic jars. Grain MC increased in airtight jars at
20oC and 30oC due to increased respiratory and metabolic activities of S. zeamais and grains. Oxygen concentration depleted in airtight jars, and CO2 increased. This might be
96 linked to increased respiratory activities of S. zeamais and grains as the temperature was increased. S. zeamais mortality was 100% in airtight jars, but 3% to 87% in non-hermetic jars. The loss in grain weight increased at 30oC because the feeding activity of S. zeamais increases with increased temperature in non-hermetic jars. The loss in grain weight was high in conventional grain compared to organic grain, and this increased as temperature was increased. The conventional grain was more susceptible to S. zeamais damage than organic grain. One S. zeamais emerged from conventional grain in non-hermetic jars at
30oC and 30 days. The emergence might be asserted to the high 30oC temperature optimal for S. zeamais growth and multiplication. Sorghum grains were safely stored in airtight jars than non-airtight jars. It was better storing grains at low temperatures compared to high temperatures. Farmers found in SSA who cannot afford grain refrigeration should first dry down grain to low MC. The low moisture grain can then be stored in airtight jars at relatively low temperature and RH to achieve reduced grain deterioration and S. zeamais infestation and damage. Sorghum seed resistant to S. zeamais can be cultivated if available.
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Gummert, M., Rickman, J., & Bell, M. (2004). Grain Storage Hermetically Sealed Systems. International Rice Research Institute. http://www.knowledgebank.irri.org/factsheetsPDFs/PostHarvest_Mangement/fs_ grainStorageHermetic.pdf. Retrieved on 9 July 2017.
Hyde, M. B., Baker, A. A., Ross, A. C., & Lopez, C. (1973). Airtight grain storage. In: J. W. Heaps (Ed.), Insect Management for Food Storage and Processing (2nd ed., pp. 105-146). St. Paul, MN, USA: FAO Agric. Serv. Bull. 17 71, AACC International.
IRRI. (2008). Grain storage and pest management. Hermetic grain storage systems. International Rice Reseach Institute. http://www.irri.org/. Retrieved on 11 July 2017.
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Malik, C. P., & Jyoti, M. (2013). Seed deterioration: A review. Int. J. LifeSc. Bt & Pharm. Res., 2(3), 375-385.
Moussa, B., Abdoulaye, T., Coulibaly, O., Baributsa, D., & Lowenberg-DeBoer, J. (2014). Adoption of on-farm hermetic storage for cowpea in the west and central Africa in 2012. Journal of Stored Products Research, 58, 77-86.
Murdock, L. L., Margam, V., Baoua, I., Balfe, S., & Shade, R. E. (2012). Death by desiccation: Effects of hermetic storage on cowpea bruchids. Journal of Stored Products Research, 49, 166-170.
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Tables
Table 3.1. Moisture Content (MC) of the Conventional and Organic Grains at 15oC.
Moisture Content (%)
Time (Day) Hermetic Non-Hermetic
Conventional Organic Conventional Organic
With Without With Without With Without With Without S. S. S. S. S. S. S. S. zeamais zeamais zeamais zeamais zeamais zeamais zeamais zeamais
0 8.99± 8.99± 9.59± 9.59± 8.99± 8.99± 9.59± 9.59± 0.08b 0.08b 0.08a 0.08a 0.08d 0.08d 0.08d 0.08d
15 8.99± 8.93± 9.59± 9.58± 14.22± 15.81± 14.55± 13.77± 0.08b 0.00b 0.08a 0.08a 0.28c 0.85ab 0.19bc 0.18c
30 - - - - 16.55± 16.41± 16.14± 16.21± 0.19a 0.00a 0.19a 0.29a
Means ± standard deviation connected by the same letter are not significantly different for hermetic or non-hermetic storage, P < 0.05. MC was not measured at 30 days in the hermetic storage.
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Table 3.2. Moisture Content (MC) of the Conventional and Organic Grains at 20oC.
Moisture Content (%)
Time (day) Hermetic Non-Hermetic
Conventional Organic Conventional Organic
With Without With Without With Without With Without S. S. S. S. S. S. S. S. zeamais zeamais zeamais zeamais zeamais zeamais zeamais zeamais
0 8.99± 8.99± 9.59± 9.59± 8.99± 8.99± 9.59± 9.59± 0.08b 0.08b 0.08a 0.08a 0.08c 0.08c 0.08c 0.08c
15 9.65± 9.41± 9.59± 9.47± 14.36± 13.90± 13.90± 14.81± 0.170a 0.00a 0.08a 0.08a 1.20ab 1.47b 0.55b 0.19ab
30 - - - - 16.48± 16.48± 15.88± 16.48± 0.29a 0.10a 0.19ab 0.10a
Means ± standard deviation connected by the same letter are not significantly different for hermetic or non-hermetic storage, P < 0.05. MC was not measured at 30 days in the hermetic storage.
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Table 3.3. Moisture Content (MC) of the Conventional and Organic Grains at 30oC.
Moisture Content (%)
Time (day) Hermetic Non-Hermetic
Conventional Organic Conventional Organic
With Without With Without With Without With Without S. S. S. S. S. S. S. S. zeamais zeamais zeamais zeamais zeamais zeamais zeamais zeamais
0 8.99± 8.99± 9.59± 9.59± 8.99± 8.99± 9.59± 9.59± 0.08d 0.08d 0.08c 0.08c 0.08c 0.08c 0.08c 0.08c
15 9.95± 9.71± 10.07± 9.89± 16.01± 15.81± 15.79± 15.78± 0.085ab 0.085b 0.08a 0.00ab 0.19ab 0.47ab 0.40ab 0.33ab
30 - - - - 16.65± 16.64± 16.65± 16.65± 0.00a 0.97a 0.00a 0.97a
Means ± standard deviation connected by the same letter are not significantly different for hermetic or non-hermetic storage, P < 0.05. MC was not measured at 30 days in the hermetic storage.
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Table 3.4. Percent Mortality of S. zeamais, and Loss of Grain Weight in the Conventional and Organic Grains in the Hermetic and Non-Hermetic Jars.
Sorghum grain type/ Mortality (%) in Mortality (%) Mean losses storage temperature hermetic jars in non-hermetic (%) in non- jars hermetic jars At 15oC (Conventional/30 days) - 10.00±14.14c 0.48±0.00bc At 15oC (Conventional/15 days) 100.00 (9 days) 3.33±4.71c 0.26±0.04c At 15oC (Organic/30 days) - 16.67±23.57c 0.23±0.02c At 15oC (Organic/15 days) 100.00 (7 days) 6.67±0.00c 0.13±0.05c At 20oC (Conventional/30 days) - 70.00±14.14ab 0.61±0.16abc At 20oC (Conventional/15 days) 100.00 (7 days) 33.33±18.86bc 0.55±0.09abc At 20oC (Organic/30 days) - 86.67±0.00a 0.13±0.05c At 20oC (Organic/15 days) 100.00 (5 days) 44.67±9.43bc 0.19±0.06c At 30oC (Conventional/30 days) 23.33±4.71c 1.02±0.19a At 30oC (Conventional/15 days) 100.00 (4 days) 20.00±9.43c 0.97±0.24ab At 30oC (Organic/30 days) - 20.00±9.43c 0.48±0.27bc At 30oC (Organic/15 days) 100.00 (4 days) 6.67±0.00c 0.30±0.01c
Means ± standard deviation in the same column connected by the same letter are not significantly different at P < 0.05. In parentheses are the number of days that the 100% mortality was achieved.
Table 3.5. Correlation between the Moisture Content of Grains, Mortality of S. zeamais, and Loss in Grain Weight
Loss (%) Mortality Moisture Significant (%) content (%) probability (5%) Loss (%) -0.08 0.70
Mortality (%) 0.04 0.86
Moisture 0.52 0.01 content (%)
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Figures
a b
Figure 3.1. The Conventional (a) and Organic (b) Grains Showing the Extent of Damage Caused by S. zeamais After 30 Days of Storage.
106
25
20
15
10 Oxygen (%) Oxygen Concentration
5
0 0 5 10 15 20
Days
Organic with S. zeamais Organic without S. zeamais Conventional with S. zeamais Conventional without S. zeamais
Figure 3.2. Oxygen Concentration Measured at 15oC for 15 Days.
107
25
20
15
10 Oxygen (%) Oxygen Concentration
5
0 0 5 10 15 20 Days
Organic with S. zeamais Organic without S. zeamais Conventional with S. zeamais Conventional without S. zeamais
Figure 3.3. Oxygen Concentration Measured at 20oC for 15 Days.
108
25
20
15
10 Oxygen (%) Oxygen Concentration 5
0 0 5 10 15 20
Days
Organic with S. zeamais Organic without S. zeamais Conventional with S. zeamais Conventional without S. zeamais
Figure 3.4. Oxygen Concentration Measured at 30oC for 15 Days.
109
15
13
11
9
7 Concentration Concentration (%)
2 5 CO
3
1
0 5 10 15 20 -1 Days
Organic with S. zeamais Organic without S. zeamais Conventional with S. zeamais Conventional without S. zeamais
Figure 3.5. Carbon Dioxide Concentration Measured at 15oC for 15 Days.
110
15
10
Concentration Concentration (%) 2
CO 5
0 0 5 10 15 20
Days
Organic with S. zeamais Organic without S. zeamais Conventional with S. zeamais Conventional without S. zeamais
Figure 3.6. Carbon Dioxide Concentration Measured at 20oC for 15 Days.
111
12
10
8
6 Concentration (%) Concentration
2 4 CO
2
0 0 5 10 15 20
Days
Organic with S. zeamais Organic without S. zeamais Conventional with S. zeamais Conventional without S. zeamais
Figure 3.7. Carbon Dioxide Concentration Measured at 30oC for 15 Days.
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CHAPTER 4. ENVIRONMENTAL ASSESSMENT AND COST ANALYSIS OF THE MANUFACTURING, TRANSPORT, AND USE OF ACTELLIC SUPER AND NEEMAZAL INSECTICIDES FOR THE TREATMENT OF MAIZE GRAINS
Modified from a manuscript to be submitted to the Applied Engineering in Agriculture
Abstract
The damage caused by Sitophilus zeamais to stored grains in Sub-Saharan Africa is enormous and has caused a rise in food insecurity for decades. The public has recommended the use of botanicals with insecticidal properties because of the environmental and human health hazards associated with the utilization of synthetic chemicals. The objectives of this study were to evaluate the environmental impacts of the active ingredients in actellic super (pirimiphos-methyl and permethrin) and NeemAzal
(azadirachtin), and to perform cost analysis on the usage of actellic super and NeemAzal for maize grain treatment. Environmental footprint associated with the manufacturing and transport of pirimiphos-methyl and permethrin was assessed with a functional unit of 1 kg of insecticides. The cost analysis on the usage of azadirachtin, and actellic super to treat maize grain was performed using a unit of Ghana cedis per kilogram of grain. Pirimiphos- methyl manufacturing had the lowest CO2 eq.kg/kg emissions and impacts (mPts/kg), and permethrin manufacturing had worse CO2 eq.kg/kg emissions and impacts. The CO2 eq.kg/kg emissions and impacts became severe when pirimiphos-methyl and permethrin were shipped by air, but CO2 eq.kg/kg emissions and impacts were encouraging when sea transport was used. Pirimiphos-methyl had the highest ecotoxicity impacts followed by azadirachtin, and then permethrin. Azadirachtin had no human health impacts. However, pirimiphos-methyl showed levels of human health impacts, and the impact due to permethrin was negligible. The price of the actellic super was about 224% less than that of
113 azadirachtin. The dollar-to-cedi exchange rate and inflation rate were so important in determining the costs of using insecticides. Treatment cost increased as grain capacity was increased irrespective of the insecticide used. Treatment cost using azadirachtin was huge compared to actellic super because azadirachtin is applied in large concentration. Although treatment cost increased as grain capacity was increased, the economies of scale favored the larger capacity.
Keywords: Treatment of maize grains; azadirachtin; actellic super; environmental assessment; cost analysis.
4.1. Introduction
The damage caused by Sitophilus zeamais to stored grains in Sub-Saharan Africa
(SSA) is enormous and has been a threat to food security for decades. Efforts to control grain infestation for decades are unprecedented. Mechanical or physical techniques (Banks,
1987; Paliwal et al., 1999; Bbosa et al., 2014; Suleiman et al., 2016), chemical treatments
(Cogburn et al., 1975; Brattsten et al., 1986; Collins et al., 2000; Huang and Subramanyam,
2004; Pourmirza, 2006; Abd-El-Aziz and Sherief, 2010); gamma irradiation ( Brown et al.,
1972; Darfour et al., 2012); and hermetic treatments (Murdock et al., 2003; Bern et al.,
2013; Murdock and Baoua, 2014) are all employed to control grain infestation and damage.
It is easy, cheap, and effective to manage grain in storage using physical techniques
(Facknath, 1993; White et al., 1997). However, the most predominant treatment method is the use of synthetic chemicals, however, the excessive use of these chemicals has many environmental and health detrimental impacts (Farage, 1989; Markowitz, 1992; Gupta et al., 2001). One of the most recently used synthetic insecticides in SSA including Ghana is actellic super. This is a broad spectrum insecticidal dust used to control many cereal weevils. Actellic super is composed of two compounds which are Pirimiphos-methyl (80
114 g) and Permethrin (15 g). Actellic super is toxic and can persist on grains for several months. The manufacturing of synthetic fertilizers and pesticides contributes more than
480x106 ton of greenhouse gas (GHG) emissions to the atmosphere each year. Carbon emissions associated with the manufacturing and transport, and storage of insecticides was
-1 estimated to be between 1.2 and 11.9 kg CO2 eq.kg (Pimentel, 1980; Lal, 2004).
The public has recommended the use of botanicals with insecticidal properties because of the health hazards and ecological challenges linked to synthetic insecticides usage. These botanicals are biodegradable, locally available, and inexpensive in controlling insects in stored products (Owusu, 2001; Cherry et al., 2005; Isman, 2006; Matta, 2010;
Danga et al., 2015). Azadirachtin is the predominant compound with insecticidal ability found in Azadirachta indica (Schmutterer, 1990). Azadirachtin pesticide (botanical) is environmentally friendly, so selective, persists shortly, pest specific, not harmful to organisms of no interest, and has low effect on the ecosystem (Koul et al., 1990; Ascher,
1993; Barrek et al., 2004). There is a worldwide increase utilization of azadirachtin insecticide to control insects due to its potency (Mordue and Blackwell, 1993).
Grain producers treat grains at a cost. The insecticides used in treating grains are bought from agrochemical agents, and prices of insecticides change with time, and this puts financial constraints on farmers. Farmers and other stakeholders need to have optimal knowledge of the chemical treatment of grain. Also understanding how synthetic chemicals and botanicals impact the environment, and the cost of maize grain treatment is important.
The objectives of this study were to evaluate the environmental impacts of the active ingredients in actellic super (pirimiphos-methyl and permethrin) and NeemAzal
115
(azadirachtin), and to perform cost analysis on the usage of actellic super and NeemAzal for maize grain treatment. The assumptions made were based on existing factors in Ghana.
4.2. Materials and Methods
4.2.1. Environmental assessment
The environmental impacts assessment of the active ingredients in actellic super
(pirimiphos-methyl and permethrin) during manufacturing and transport, and human health and ecotoxicity impacts assessment associated with the usage of pirimiphos-methyl, permethrin, and azadirachtin (NeemAzal) were performed. Sustainable Minds database was used for the manufacturing and transport impacts assessment of pirimiphos-methyl and permethrin, and TRACI (Tool for the Reduction and Assessment of Chemical and other Environmental Impacts) database was used for the human health and ecotoxicity impacts assessment of pirimiphos-methyl, permethrin, and azadirachtin. This is not a full life cycle assessment (LCA).
4.2.1.1. Goal and scope
The goal of this study was to evaluate the environmental, human health, and ecotoxicity impacts of pirimiphos-methyl, permethrin, and azadirachtin. This was to help farmers and decision-makers decide on the appropriate insecticide (synthetic or botanical) to use.
4.2.1.2. Functional unit
The focus of this study was on the active ingredients in actellic super (synthetic) and NeemAzal (botanical) insecticides which are used to treat maize grain. Therefore, a functional unit of 1 kg of pirimiphos-methyl, and permethrin was used in the manufacturing and transport analysis. The functional unit of the ecotoxicity and human health impacts
116 was based on the quantity (kg) of pirimiphos-methyl, permethrin, and azadirachtin required to treat 1 kg of maize grain.
4.2.1.3. System boundary
Figure 4.1 shows the system boundary for the manufacturing and transport of pirimiphos-methyl and permethrin, and usage of pirimiphos-methyl, permethrin, and azadirachtin.
4.2.1.4. Impacts categories
The impacts categories for this study were global warming potential (CO2 equivalent emissions and impacts), human health impacts (cancer or non-cancer) and ecotoxicity impacts.
4.2.1.5. Assumptions and estimates
Since actellic super is most commonly imported from Kenya, freight from Kenya to Ghana was assumed to be 2739 mi (air), and 5862.071 mi (Sea: Via Cape of Good Hope,
10 Knots). Actellic super contains pirimiphos-methyl (16 g/kg), and permethrin (3 g/kg),
-2 and the application rate used was 5.0x10 kg per 90 kg of maize (according to users’
-4 -4 protocol). Regarding the 5.6x10 kg per 1 kg of maize grain, 4.7x10 kg of pirimiphos-
-5 methyl, and 8.8x10 kg of permethrin were required to treat 1 kg of grain. According to
Nukenine et al. (2011), 0.012 kg of NeemAzal is required to treat 1 kg of maize to achieve
-2 99% mortality within 14 days. Therefore, 1.2x10 kg of azadirachtin was applied to 1 kg of grain in the analysis.
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4.2.2. Cost Analysis
4.2.2.1. Goal and scope
The cost analysis of maize grain treatment using actellic super and NeemAzal
(azadirachtin) was performed. This can help farmers select the most cost-effective insecticide (natural or synthetic) to use.
4.2.2.2. Unit cost of treatment
The unit cost of treatment used was Ghana cedi per 1 kg of grain (GHȻ/kg). Thus, the cost of treating 1 kg of grain using azadirachtin and actellic super.
4.2.2.3. System boundary
Domestic transport fares, costs of other handling implements (like gloves, nose mask, etc.), and cost of the woven polypropylene storage bags were excluded from the analysis. The costs are similar in both case scenarios. Farming inputs and structures, and storage materials (bins or bags) were not considered in the system boundary.
4.2.2.4. Assumptions and estimates
The grain storage period was assumed to be 6 months. The average baseline costs of treating 1 kg of maize grain were GHȻ0.0112 and GHȻ0.005 for NeemAzal and actellic super, respectively (based on agrochemical shops in Ghana). Dollar-to-cedi exchange rate and an inflation rate of minus 50%, and plus 50% and 100% were used. Based on the baseline costs, the cost analysis was performed using 1, 500, 1000, 1500, 2000 and 2500 kg grain capacities. Percent rebate was applied to purchasing a larger quantity of insecticides based on the price list used by FREB Pharmaceuticals Ltd (agrochemicals producer/agent in Kenya on January 29, 2015). The rebates used were 15%, 30%, 45%,
60%, and 75%, and was applied at 500 kg grain capacity intervals. However, insecticides’
118 price rebate of 75% was applied to 2500 kg (and above) grain capacity. The data were graphed, and regression analysis was then applied.
4.3. Results and Discussion
4.3.1. Global warming potential (CO2 equivalent emissions and impacts)
The CO2 eq. emissions impacts measured were ecological, resource depletion, and human health damage (fig. 4.2). Generally, pirimiphos-methyl manufacturing had the lowest CO2 eq. emissions and impacts (9.6 CO2 eq.kg/kg and 0.71 mPts/kg). Permethrin manufacturing was worse concerning CO2 eq. emissions and impacts (25 CO2 eq.kg/kg and
1.7 mPts/kg). Permethrin manufacturing emitted 15.4 CO2 eq.kg/kg higher than pirimiphos-methyl manufacturing. Pirimiphos-methyl manufacturing and transport (sea and air) was even better than permethrin manufacturing regarding CO2 eq. emissions and impacts. The emissions (CO2 eq.kg/kg) and impacts (mPts/kg) were severe when pirimiphos-methyl and permethrin were shipped by air from Kenya to Ghana. For example, air transport of permethrin emitted 11.0 kg CO2 eq. more than permethrin manufacturing.
Air transport of pirimiphos-methyl emitted 10.4 CO2 eq.kg/kg more than pirimiphos- methyl manufacturing. However, CO2 eq.kg/kg emissions and impacts (mPts/kg) of the sea transport of pirimiphos-methyl and permethrin were similar to their manufacturing.
Carbon emissions associated with manufacturing and transport, and storage of insecticides was estimated to be between 1.2 and 8.1 kg CO2 eq./kg (Pimentel, 1980). West and Marland (2002) estimated 4.6 kg CO2 eq./kg emissions in manufacturing, packaging, and transport of insecticides. About 1.2-11.9 kg CO2 eq./kg emitted from insecticides manufacturing was reported by Lal (2004), after recalculating carbon equivalent from earlier reports. The pirimiphos-methyl manufacturing emissions (CO2 eq.kg/kg) for this study was within the CO2 eq.kg/kg range reported by Lal (2004). But the emissions (CO2
119 eq.kg/kg) from permethrin manufacturing was above that range. Thus, permethrin manufacturing contributes largely to GHG emissions and global warming, hence its manufacturing must be stopped. To ensure permethrin and pirimiphos-methyl are not manufactured, farmers could be entreated to desist from the purchase and use of actellic super. According to PAN-Germany (2010), permethrin (pyrethroid) is highly toxic to bees.
The EPA (US) listed permethrin (pyrethroid) as a possible human carcinogen, highly bioaccumulative, and persistent in water. Therefore, the use of permethrin affects food security, the health of humans, the environment, and causes global warming. Importantly, pirimiphos-methyl (organophosphate) is not classified among the most dangerous pesticide
(PAN-Germany, 2010). Pirimiphos-methyl manufacturing had low emissions (CO2 eq.kg/kg) and impacts (mPts/kg), but its composition in actellic super is five times more than permethrin. Therefore, GHG and global warming effects of pirimiphos-methyl might be similar to permethrin. Hence, the manufacturing and transport of pirimiphos-methyl and permethrin should be discouraged. However, if the manufacturing and transport could not be stopped, then sea transport of actellic super could be encouraged. This could
-1 substantially reduce CO2 eq.kg emissions and impacts (mPts/kg) associated with the transport of actellic super to Ghana.
4.3.2. Ecotoxicity and human health impacts
The ecotoxicity impacts associated with using azadirachtin, pirimiphos-methyl, and permethrin were determined (fig. 4.3). All three chemicals seriously impacted water, but negligibly impacted air and soil. Their easy solubility in water might have caused the heavy impact on water. However, the limited moisture in air and soil might have resulted in low solubility and ecotoxicity impacts. Similar impacts on water were recorded using pirimiphos-methyl (128.0 CTUeco/kg), azadirachtin (115.0 CTUeco/kg), and permethrin
120
(104.0 CTUeco/kg). Azadirachtin had the highest ecotoxicity impacts on air, followed by permethrin, and pirimiphos-methyl. Azadirachtin had the highest ecotoxicity impacts on soil, followed by pirimiphos-methyl, but permethrin had a very low impact on soil. When air, water, and soil were combined, total ecotoxicity impact was pirimiphos-methyl (134.0
CTUeco/kg), azadirachtin (124.0 CTUeco/kg), and permethrin (106.0 CTUeco/kg).
Figure 4.4 shows the health effects associated with using azadirachtin, pirimiphos- methyl, and permethrin. Azadirachtin did not record any human health impacts (0
CTUnoncancer/kg). However, human health impacts using pirimiphos-methyl was
-8 -10 1.63x10 CTUnoncancer/kg, and negligible using permethrin (2.58x10
CTUnoncancer/kg). Human health impacts due to insecticide contaminated water were
-08 high compared to soil and air. Thus, 1.31x10 CTUnoncancer/kg (pirimiphos-methyl) and
-10 1.51x10 CTUnoncancer/kg (permethrin). The high water ecotoxicity impact resulted in high human health impacts (non-cancer) due to water.
To have effective insect mortality, pirimiphos-methyl and azadirachtin are applied
-2 -4 -5 in large masses. About 1.2x10 kg, 4.7x10 kg and 8.8x10 kg of azadirachtin, pirimiphos- methyl, and permethrin, respectively, were used to treat 1 kg of grain. Therefore, the relatively large mass might have resulted in high ecotoxicity impacts of azadirachtin and pirimiphos-methyl. The low ecotoxicity and human health impacts of permethrin might be due to the smaller mass used. Despite the smaller mass of permethrin (88 mg/kg) used, when the ecotoxicity and human health impacts are compared to azadirachtin and pirimiphos-methyl, permethrin usage cannot be considered friendly environmentally and healthwise. If permethrin had been used in a larger mass as azadirachtin (12000 mg/kg), ecotoxicity and human health impacts would have been overwhelming. According to PAN-
121
Germany (2010), permethrin is more toxic compared to azadirachtin and pirimiphos- methyl. The low composition of permethrin in actellic super might be due to its ecotoxicity and human health impacts potency. Generally, human health impacts of azadirachtin and permethrin were better, and the ecotoxicity impacts of permethrin were better.
The Penn State Extension (2006) categorized insecticides containing azadirachtin, pirimiphos-methyl, and permethrin into “Toxicity Category III” (thus, to be used with caution). Worth noting, azadirachtin was designated to be of general use, and pirimiphos- methyl and permethrin were designated to be of restricted use. In their report, azadirachtin toxicity effects (LD50) required massive concentrations (5000 mg/kg or more in oral use; and 2000 mg/kg or more in dermal use). Although the mass of azadirachtin used in this study was 12000 mg/kg, higher than the 5000 mg/kg, there were no human health impacts.
Hence, this study affirms the assertion that azadirachtin (NeemAzal) is specific to the target organism. Therefore, in a worst-case scenario, farmers can use azadirachtin (NeemAzal) to treat grains without any health concerns. Azadirachtin is preferred to pirimiphos-methyl and permethrin because it is usually safer for non-target organisms, and the environment
(Buss and Park-Brown, 2002; Charleston et al., 2006). Reports indicate that azadirachtin insecticide is environmentally friendly, so selective, transient, pests-specific, harmless to another organism of no interest, and has low effect on the ecosystem (Mordue and
Blackwell, 1993; Ascher, 1993; Barrek et al., 2004). Encouraging global use of botanical insecticides like NeemAzal (Azadirachtin) would overcome many ecological and environmental challenges.
Pirimiphos-methyl is required in a smaller mass to cause toxicity effects (LD50)
(tech. 5-20 mg/kg, oral; 220 mg/kg, dermal). Pirimiphos-methyl has a broader toxicity
122 effect include oral, dermal, inhalation, accident, wildlife, fish, and aquatic species. The high ecotoxicity and human health impacts of pirimiphos-methyl could be attributed to its broader toxicity effect. Actellic super must be handled with caution as its major compositions (pirimiphos-methyl and permethrin) have broad-spectrum toxicity effects.
Permethrin is a broad-spectrum and restricted insecticide, and highly dangerous for bees, fish and aquatic species. Unlike pirimiphos-methyl, permethrin is required in a higher mass to cause toxicity effects (tech. >4000 mg/kg, oral; >4000 mg/kg, dermal), and are generally harmless to humans (Penn State Extension, 2006). Importantly, unlike pirimiphos-methyl that highly bioaccumulates and persists, permethrin decomposes in the soil within a few days (Toynton et al., 2009).
4.3.3. Cost analysis
The cost of treating 1 kg of maize grain was higher using azadirachtin compared to actellic super. The price of azadirachtin was about 224% higher than the actellic super (fig.
4.5). The increase in treatment costs using actellic super or azadirachtin corresponded with the increased inflation rate. When grain capacity was increased, treatment costs also increased non-linearly. However, treatment cost using azadirachtin was higher than actellic super (fig. 4.6). Change in treatment cost using actellic super or azadirachtin increased proportionally with grain capacity (fig. 4.7). Huge cost differences occurred between 1 kg,
500 kg, 1,500 kg, and 2,000 kg capacities, but negligible cost difference occurred between
2,000 kg and 2,500 kg. The graph shows that treatment costs increased as grain capacity increased. Infinite application of price rebate (%) on actellic super or azadirachtin could have decreased the treatment costs to negative values. The unit treatment cost (economies of scale) decreased as grain capacity increased (fig. 4.8).
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Since the inflation rate had an effect on the price of insecticides, when the inflation rate was low the treatment cost decreased. NeemAzal and actellic super are imported into
Ghana, hence their prices depend on the exchange rate. When the exchange rate increases farmers in Ghana would have to purchase insecticides at a high price. Therefore, an increase in inflation and exchange rates can make treatment cost very expensive to farmers.
The non-linearity of treatment cost with increasing capacity due to the applied rebates (%) was essential. There was value for money handling larger grain capacities. Treatment cost of 2,500 kg capacity decreased as price rebate (%) on insecticides was highest, and beyond that capacity price rebate (%) remained constant. The polynomial regression equation could better predict (R2 = 1) treatment costs, and differences in costs when actellic super or azadirachtin is to be used. Similarly, the polynomial regression equation could better predict the unit cost of treatment (R2 = 1). So, a substantial lower treatment cost can be achieved when farmers treat large grain capacities. Thus, farmers can enjoy a high rebate
(%) on the price of insecticides. Smallholder farmers in Ghana and other SSA do not enjoy huge rebates (%) on prices of insecticides. Because they harvest small quantities of grain, and hence experience expensive treatment cost. PHL is massive among farmers financially constrained to purchase insecticides.
At all levels of grain capacity, treatment costs were high when azadirachtin used.
Surmising, the high treatment cost was due to the large quantity (mass) of azadirachtin required to treat grain. Basically, prices of botanical insecticides are high compared to synthetic insecticides (Shabozoi et al., 2011; Amoabeng et al., 2014; Ngbede et al., 2014).
The large quantity of azadirachtin required coupled with a high market price limit its usage among farmers. Although azadirachtin (NeemAzal) or any other botanical insecticide is
124 friendly environmentally and healthwise, it is very expensive to use. Farmers that used botanical insecticides experienced less economic benefits (Leatemia, 2003). Farmers then opt for synthetic insecticides which are detrimental to their health, consumers, and the environment. Mostly, botanical insecticides are scarce in markets, and therefore farmers in
SSA who can even afford to buy do not have access to them.
Essentially, to avoid treatment cost associated with using botanical or synthetic insecticides, farmers in Ghana (SSA) can apply plant materials (leaves, seeds, branches, powders) from neem, pepper, basil, etc. plants. Smallholder farmers can have temporary financial relief if the grain is stored shortly. According to Amoabeng et al. (2014), local plant materials are inexpensive to use compared to synthetic insecticides.
4.4. Conclusions
Pirimiphos-methyl manufacturing had the lowest CO2 eq.kg/kg emissions and impacts (mPts/kg), and permethrin manufacturing had worse CO2 eq.kg/kg emissions and impacts (mPts/kg). Pirimiphos-methyl manufacturing and transport (sea and air) even had low CO2 eq.kg/kg emissions and impacts (mPts/kg) compared to permethrin manufacturing only. Importantly, sea transport of pirimiphos-methyl and permethrin recorded low CO2 eq.kg/kg emissions and impacts (mPts/kg) compared to air transport. Hence, permethrin manufacturing and air transport of pirimiphos-methyl and permethrin should be discouraged to reduce GHG emission effects and global warming. Pirimiphos-methyl had the highest ecotoxicity impacts, and permethrin had the lowest. The large mass of azadirachtin used might have resulted in the second highest ecotoxicity impacts.
Azadirachtin did not have any human health impacts (cancer and non-cancer). But pirimiphos-methyl had human health impacts, and human health impacts of permethrin were negligible. Hence, this study affirms the assertion that azadirachtin (NeemAzal) is
125 specific to the target organism. Therefore, in a worst-case scenario, farmers can use azadirachtin (NeemAzal) to treat grains without any health concerns. The high ecotoxicity and human health impacts of pirimiphos-methyl could be attributed to its broader toxicity effect. The low ecotoxicity and human health impacts of permethrin might be due to the smaller mass used. Despite the smaller mass of permethrin used, when the ecotoxicity and human health impacts are compared to azadirachtin and pirimiphos-methyl, permethrin usage cannot be considered friendly environmentally and healthwise. If permethrin had been used in a larger mass as azadirachtin, ecotoxicity and human health impacts would have been overwhelming.
The price of the azadirachtin was about 224% higher than actellic super. NeemAzal and actellic super are imported into Ghana, hence their prices depend on the exchange rate.
Therefore, an increase in inflation and exchange rates can make treatment cost very expensive to farmers. The non-linearity of treatment cost with increasing capacity due to the applied rebates (%) was essential. Because of the smaller quantity of harvest, smallholder farmers in Ghana do not enjoy huge rebates (%) on prices of insecticides.
Hence, farmers experience expensive treatment cost and high PHL. Azadirachtin has a high price, scarce in markets and required in a large mass, hence treatment cost is expensive to smallholder farmers in SSA. Farmers then opt for synthetic insecticides which are detrimental to their health, consumers, and the environment. Farmers also do not benefit from reduced treatment cost associated with economies of scale.
126
4.5. References
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Amoabeng, B. W., Gurr, G. M., Gitau, C. W., & Stevenson, P. C. (2014). Cost-Benefit analysis of botanical insecticide use in cabbage: Implications for smallholder farmers in developing countries. Crop Protection, 57, 71-76.
Ascher, K. R. S. (1993). Non-conventional insecticidal effects of pesticides available from the Neem tree, Azadirachta indica. Archives of Insect Biochemistry and Physiology, 22, 433-49.
Banks, H. J. (1987). Impacts, physical removal and exclusion for insect control in stored products, In: E. Donahaye & S. Navarro (Eds.), Stored-Product Protection. Proc. 4th Intl. Working Conference, pp. 165-184. Maor-Wallach Press, Caspit, Jerusalem.
Barrek, S., Olivier, P., & Grenier-Loustalot, M. F. (2004). Analysis of neem oils by LC- MS and degradation kinetics of azadirachtin-A in a controlled environment: characterization of degradation products by HPLC–MS-MS. Analytical and Bioanalytical Chemistry, 378(7), 53-63.
Bbosa, D., Brumm, T. J., Bern, C. J., & Rosentrater, K. A. (2014). Evaluation of hermetic maize storage for smallholder farmers. Proceedings and Presentations of ICABBBE 16th International Conference on Agricultural and Biosystems Engineering Conference. Paper No. 380. Los Angeles: ASABE.
Bern, C. J., Yakubu, A., Brumm, T. J., & Rosentrater, K. A. (2013). Hermetic storage systems for maize stored on subsistence farms. ASABE Annual International Meeting. Paper No. 131591815. St. Joseph, MI: ASABE.
Brattsten, L. B., Holyoke, C. W., Leeper, J. R., & Affa, k. F. (1986). Insecticide resistance: Challenge to pest management and basic research. Science, 231, 1125-1160.
Brown, G. A., Brower, J. H., & Tilton, E. W. (1972). Gamma Radiation Effects on Sitophilus zeamais and S. granarius. Journal of Economic Entomology, 65, 203- 205.
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Figures
The transport of The manufacturing of insecticides The use of insecticides insecticides (freight: Sea and Air)
Figure 4.1. System Boundary for the Environmental Assessment: Sustainable Minds was used for the Manufacturing and Transport of Insecticides and TRACI was Used for Insecticides Usage.
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45
CO2 eq.kg/kg mPts/kg (Impact per fnal unit) 40
35
30
25
20 eq. emissions impacts emissions andeq.
2 15 CO
10
5
0 Pirimiphos methyl Pirimiphos methyl Pirimiphos methyl Permethrin Permethrin Permethrin (Manufacturing) (Manufacturing & (Manufacturing & (Manufacturing) (Manufacturing & (Manufacturing & Sea Transport) air Transport) Sea Transport) air Transport )
Figure 4.2. CO2 Equivalent Emissions and Impacts of Pirimiphos-Methyl and Permethrin during Manufacturing and Transport (Air and Sea Freights) ) per kg of insecticide. Impact per FU (mPts) = ecological, resource depletion and human health damage.
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1.60E+02
1.40E+02
1.20E+02
1.00E+02
8.00E+01
6.00E+01
4.00E+01 Ecotoxicity (CTUeco/kg) impacts Ecotoxicity
2.00E+01
0.00E+00 Azadirachtin Pirimiphos-methyl Permethrin
Impact eco(CTUeco/kg) Air Impact eco(CTUeco/kg) Water Impact eco(CTUeco/kg) Soil
Figure 4.3. Ecotoxicity Impacts of Azadirachtin, Pirimiphos-Methyl, and Permethrin usage to Air, Water, and Soil per 1 kg of maize grain.
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1.80E-08
1.60E-08
1.40E-08
1.20E-08
1.00E-08
8.00E-09
6.00E-09 Human health (CTUnoncancer/kg) health impacts Human 4.00E-09
2.00E-09
0.00E+00 Azadirachtin Pirimiphos-methyl Permethrin
Human health impact (CTUnoncancer/kg) Soil Human health impact (CTUnoncancer/kg) Water Human health impact (CTUnoncancer/kg) Air
Figure 4.4. Human Health Impacts of Azadirachtin, Pirimiphos-Methyl, and Permethrin usage to Air, Water, and Soil per 1 kg of maize grain.
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0.035
0.03
0.025
0.02
0.015
0.01 Costs of treating maize(Ȼ/kg) of Coststreating 0.005
0 present -0.5 0.5 1
Azadirachtin Actellic super
Figure 4.5. The Costs of Azadirachtin and Actellic Super Per Treatment of 1 kg of Maize at Present Price, and Dollar-to-Cedi Exchange Rate and an Inflation Rate of -50%, 50%, and 100%.
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0.12
0.1
0.08 y = -4E-08x2 + 0.0001x R² = 1
0.06
0.04 Total cost of treatment treatment of (Ȼ) cost Total
0.02
y = -8E-10x2 + 3E-06x + 7E-10 R² = 1 0 0 500 1000 1500 2000 2500 3000
Capacity of maize (kg)
Azadirachtin (Ȼ) Actellic Super (Ȼ)
Poly. (Azadirachtin (Ȼ)) Poly. (Actellic Super (Ȼ))
Figure 4.6. Costs of Treating 1 kg, 500 kg, 1000 kg, 1500 kg, 2000 kg, and 2500 kg Capacities of Maize Grains by Using Azadirachtin and Actellic Super.
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0.12
0.1
0.08 y = -4E-08x2 + 0.0001x + 3E-08 R² = 1
0.06
0.04 The difference in the cost of treatment (Ȼ) treatment of cost the in difference The 0.02
0 0 500 1000 1500 2000 2500 3000
Capacity of maize (kg)
Cost (Ȼ) Poly. (Cost (Ȼ))
Figure 4.7. Change in the Costs of Treatment by Using Azadirachtin and Actellic Super at Different Capacities of Grains (kg).
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0.00016
0.00014
0.00012 y = 1E-14x2 - 4E-08x + 0.0001 R² = 1
0.0001
0.00008
0.00006 Unit cost of treating Unitcost of treating grain maize(Ȼ/kg) 0.00004
0.00002 y = 3E-16x2 - 8E-10x + 3E-06 R² = 1 0 0 500 1000 1500 2000 2500 3000
Capacity of maize grain (kg)
Azadirachtin (Ȼ/kg) Actellic Super (Ȼ/kg) Poly. (Azadirachtin (Ȼ/kg)) Poly. (Actellic Super (Ȼ/kg))
Figure 4.8. The Unit Cost of Treating Maize Grain in Ghana (Economies of Scale).
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CHAPTER 5. PRE-HARVEST AND POST-HARVEST FARMER EXPERIENCES AND PRACTICES IN FIVE MAIZE GROWING REGIONS IN GHANA
Modified from a manuscript to be submitted to the Applied Engineering in Agriculture
Abstract
Maize is a major staple crop mainly produced by smallholder farmers in developing nations. Grain losses happen in Sub-Saharan Africa, and therefore the objective of this study was to assess the different kinds of pre-harvest and post-harvest losses that maize farmers in Ghana encounter. The storage practices, and farmers’ awareness and knowledge of mycotoxin contamination in maize were also assessed. The study area had five regions, and each region had three districts. The study sites were selected purposefully because of the prior knowledge on high maize production. A semi-structured questionnaire was used to collect the data, and a purposive sampling technique was used to select 75 maize farmers for the interview. The male maize farmers were many compared to females. Over 70% of farmers were at least 40 years. Except for the northern region, farmers (>50%) have completed at least basic education. At least 90% of farmers experienced about 2% or less pre-harvest losses. Grain yields were low as farmers did not apply fertilizers, herbicides, pesticides or insecticides due to financial constraints. Farmers observed PHL of about 60% to 100%. Typically, grains were stored in polypropylene bags for a period of 3 to 12 months. Farmers used a synthetic chemical treatment, however, some used leaves from pepper, basil, and neem plants to kill or repel maize weevils in stored grain. The northern region had the highest usage of plant material for grain treatment, but the least maize weevil infestations (%).
Keywords: Pre-harvest losses; Post-harvest losses; Maize grain storage; Ghana.
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5.1. Introduction
Maize is a major staple crop produced and consumed in Ghana at the smallholder level. At least maize accounts for 50% of Ghana’s cereal production (Ragasa et al., 2014).
Maize crop is well adapted in most of the ecological zones in Ghana (Adu et al., 2014).
However, they are dominantly grown in the middle to southern zones (Rondon and Ashitey,
2011). The agro-ecological zones for maize are grouped into four with different cultivation system (Morris et al., 1999). Maize grain is highly used at a household level than industrial scale. After harvest, maize grain is dried, cleaned, treated and stored, and protected from pests, and moisture increase (Darfour and Rosentrater, 2016a). For decades, many traditional methods are applied to keep grains in safe storage. Many modern and advanced post-harvest techniques contemporary exist. Farmers in Ghana appreciate the importance of modern techniques in grain storage (Darfour and Rosentrater, 2016a). Maize post- harvest loss (PHL) is reported to be between 5% and 70% (FAOSTAT/FAO, 2012). To improve food security, PHL in grains should be reduced. Because PHL increases food prices and reduces access and availability of nutritious food. Farmer’s purchasing power reduces and poverty level then rises (Opit, 2014). PHL in SSA is still high although steadily decreasing, therefore the aim of this study was to assess the different kinds of pre-harvest and post-harvest losses that maize farmers in Ghana encounter. The storage practices, and farmers’ awareness and knowledge of mycotoxin contamination in maize were also assessed.
5.2. Materials and Methods
5.2.1. The study area and administering of interviews in Ghana
A pre-survey was tested in Akuapim South District in mid-May, 2016. The actual study area had five regions, and each region had three districts. The study sites were
140 selected purposefully because of the prior knowledge on high maize production (Edwards,
1995; Morris et al., 1999; Rondon and Ashitey, 2011; Darfour and Rosentrater, 2016 a, b).
A semi-structured questionnaire was used to collect the data. A purposive sampling technique was used to select 75 maize farmers that were interviewed (table 5.1) between
May and August 2016 through the efforts of their Agricultural Extension Agents (AEAs).
Questions were asked on the major causes of pre-harvest and post-harvest losses in maize, methods and length of maize storage, grain handling practices, knowledge of mycotoxin contamination, etc. (Appendix 5.1). Questions were asked in participants’ local language.
5.2.2. Data presentation
The data were coded and calculated in percentages. The data set (%) was tabulated or graphed accordingly. The data trend was described using descriptive statistics.
5.3. Results and Discussion
5.3.1. Demographic information on farmers
The percentage of male farmers exceeded female counterparts based on the five regions surveyed (table 5.2). This result contradicts the perception that female farmers in
Ghana outnumber their male counterparts. Jolly et al. (2009) similarly indicated that male farmers in Ghana outnumber females. Contrary, research in Tanzania and Nigeria have reported a high percentage of female farmers than males (Ellis et al., 2007; Ogunlela and
Mukhtar, 2009; Suleiman et al., 2016). Women in agriculture (%) found in SSA and other developing countries ranges between 43% and 50% (FAO, 2012). Based on the regions surveyed, more than 60% of farmers were at least 40 years old. If this situation happens to be experienced across all regions in Ghana, then Ghana could have a decline in the agricultural workforce in the near future. This can lead to limited food supply and massive food insecurity and poverty. Farms were family managed and headed by men. Unlike wives
141 of male farmers that cultivated 1 acre of land to support their husbands, single-parent females cultivated 2-3 acres. Ghanaian farmers commonly measure land size in acres.
At least 50% of farmers completed primary education, except farmers in NR. This infers that most farmers can read or write or understand basic information delivered by their AEAs. The number of farmers without formal education was highest in BA (47%) and NR (87%). About 13% of farmers in NR completed primary education, and that was their highest. However, most farmers depend on their colleagues for information on good farming practices. Especially in NR, farmers depended mostly on their AEAs and colleagues. Similarly, Suleiman et al. (2016) reported that in Tanzania most maize farmers completed at least primary education. Importantly, farmers in all regions that completed college-level education were regular formal sector workers. Farming was a part-time activity to complement their salaries and family incomes.
5.3.2. Cultivated farm size, and grain handling before, during and after harvest
About 73% of farmers cultivated 2 to 5 acres of land in BA, CR, and ER (table 5.3).
About 67% and 53% of farmers cultivated 2 to 5 acres of land in AR and NR, respectively.
Twenty percent of farmers cultivated between 6 and 10 acres of land in BA and NR. Since farmers typically cultivated fewer acres of land, they are within the category of smallholder farmers. According to FAO (2012), smallholder farmers cultivate at most 25 acres (10 ha) of land. Most farmers in SSA are within this category, and that could be the reason for the low food productivity and high poverty among farmers.
Farmers that experienced pre-harvest losses were between 93% and 100% (table
5.4). However, pre-harvest losses were mostly less than 1%, except NR that was 2%.
Causative agents of pre-harvest losses and intensity of damage varied and depended on the farming area. The common causative agents were birds, weather, insects, plant lodging,
142 and rodents. Plant lodging was the most dominant and uncontrollable and was caused by termites or wind or rodents. Farmers can use bait traps to control rodents but they have no control over wind and termites. Essentially, pre-harvest losses are low in Ghana, and therefore do not contribute much to food insecurity. Farmers did not apply insecticides to control termites, birds, and insects before harvest. This maintains the natural bio-ecosystem and the environment. Nonetheless, when grain harvest delays, in-field weevils infested grains are carried to storage. When harvesting is delayed, grain vulnerability to insects and molds in the field worsens (Kaaya et al., 2005).
All farmers typically harvested maize using a handheld machete (table 5.3).
Because of the manual harvesting method used, harvesting mostly lasted a few days to 2 weeks (table 5.5). Farmers had no access to harvest combines which delayed harvesting and further increased the intensity of maize weevils’ infestation. Farmers that cultivated larger acres hired casual laborers to help during harvesting. Farmers in CR and BA that harvested between 500 and 3000 kg of grain were 20% and 27%, respectively. Farmers in
ER that harvested about 1500 kg of grain were 86%. About 60% of farmers in AR harvested between 500 and 3000 kg, and 33% of farmers harvested at least 3000 kg. About 93% of farmers in NR harvested between 500 and 3000 kg. Grain yield was low compared to developed nations. Non-mechanized farming operations, dependence on rainfall, and the inability to purchase and apply farming inputs might have resulted in low yields. Such inputs are fertilizers, herbicides, pesticides, insecticides, machetes, etc. Farmers complained about unavailable financial loans and limited government subsidies on agriculture inputs. To increase maize production, it is important to mechanize farming practices and increase government subsidies on agriculture inputs. Abass et al. (2014)
143 observed a low yield among maize farmers in Tanzania, and they attributed it to manual farming operations. To avoid hustle associated with post-harvest handling of grain, most farmers in ER sold maize as sweet corn (green stage) instead of physiologically matured grain (dry stage). However, the practice affects food security as grain becomes scarce and expensive during peak seasons of grain usage.
Farmers threshed grain using their hand, beating or the combination of hand and beating methods. As shown in table 5.5, methods used in grain threshing depended on farmers’ preference and convenience. It is noteworthy that about 73%, 40%, 33% of farmers, respectively in BA, AR and NR threshed grain mechanically. High losses are associated with most non-mechanized threshing methods. However, farmers equally complained about high losses when locally made shelling machines are used (fig. 5.2).
Most of the available shelling machines are locally made and have low efficiency which resulted in high grain losses and damage. Interestingly, owners of shelling machines operate on a barter trade system. A few farmers used improvised tools (fig. 5.1) in grain shelling. If farmers are provided with mechanical shelling machines of high efficiency, grain damage and losses could reduce to subsequently increase food security. Manual grain shelling in Tanzania was reported by Abass et al. (2014).
5.3.3. Post-harvest grain drying, sorting, and storage
Months of grain storage depended on farmers’ preference but varied between weeks to 12 months (table 5.5). About 93% to 100% of farmers in all regions used sun drying, and only 7% in AR used solar drying (table 5.6). Some farmers depended on in field drying before harvest. During sun drying, the grain lot is spread on bare floors or cemented pads or mats or tarpaulins or large polyethylene to dry in the sun. The grain lot is exposed to birds, foreign contaminants, livestock, and unexpected rainfall (fig. 5.3). All these factors
144 increase grain losses and reduce grain quantity and quality, which cumulates to increase poverty and food insecurity. The solar drying tent essentially maintains grain quality and quantity.
About 67% to 100% of farmers sorted grain. Foreign materials, mold or insect- infested kernel, broken kernels, broken cob, etc. were removed. At least 67% of farmers sorted grain by handpicking or winnowing. Although most farmers sorted their grain, the sorting was not efficient, hence grain deterioration was high. Grain sorting reduces grain spoilage (Hell et al., 2008), and also maintains grain quantity, quality, and grade.
Some farmers currently use traditional granary and/or and polypropylene bags (fig.
5.4a and b). At least 60% of farmers in AR, BA, and NR used polypropylene bags to store grain. The traditional granary was highly used in ER and CR. The traditional granary is susceptible to insects and rodents attack, and grain losses are usually very high compared to polypropylene bags. The usage of hermetic storage technique was limited, only one female farmer in ER kept grain hermetically in plastic gallons (fig. 5.1). Hermetic storage and metal silos are essential in safe storage of grain. But farmers were not using the two techniques during storage, and therefore grain PHL was high. More than 87% of farmers sold a higher percentage of the harvested grain and kept the rest for domestic use. Farmers that experienced financial difficulty sold their grain a few weeks after harvest. Typically, due to the two growing seasons in CR, ER, AR, and BA, most farmers did not store grain above 6 months, except the grain retained for domestic use. Farmers decided to avoid long- term storage to prevent insects’ infestation.
5.3.4. Post-harvest grain treatment, and use of damaged ears
About 87% of farmers in the CR used synthetic insecticides in grain treatment (table
5.7). In ER and AR, almost half of the farmers (%) either used or did not use synthetic
145 insecticides. About 20% of farmers in BA used synthetic insecticides, and 40% in NR used fumigants. Farmers that applied plant materials in grain treatment was 87%, 27%, and 7% in NR, ER, and AR, respectively. A few farmers applied synthetic insecticides in BA because most farmers sold out grain days or weeks just after harvest, hence chemical treatment was unnecessary. Most farmers in NR used plant materials to treat grain, hence low synthetic insecticides (fumigants) application. Some farmers in NR used a combination of fumigants and plant materials during grain storage. Farmers claimed that the fumigants acted as rodent repellent, and to prevent maize weevil re-infestations. Farmers that used synthetic insecticides complained about the misuse and misapplication of insecticides by their colleagues. Common insecticides used by farmers included actellic super, phosphine
(fumigant), etc. Despite the high application of plant materials instead of insecticides or fumigants in NR, maize weevil infestation was very low. The common plant materials used by farmers that participated in the interview included neem, red hot pepper and basil plants
(fig. 5.5). The seeds or leaves from plants were applied in whole, dry or fresh (wet) or powder forms. If farmers’ claim on plant materials usage is right, then farmers should opt for plant materials instead of synthetic insecticides to save income and protect the health of farmers and consumers. In this survey, farmers did not extract the insecticidal essential oils from plant materials before use. However, insecticidal essential oils extracted from many plants were potent against insects (Christian and Goggi, 2008; Benzi et al., 2009;
Ebadollahi et al., 2010; Ayvaz et al., 2010). Farmers used damaged ears as animal feed or human food, sold, and discarded severely infested ears.
5.3.5. Molds infestation, knowledge of farmers, and AEAs’ activities
Farmers that experienced post-harvest molds attack was between 13% and 40%, and BA was the highest. At least 90% of farmers in all regions had an idea on the effects
146 of using moldy grain. Therefore, we expect farmers not to use moldy grain as animal feed or food or sell to unsuspecting consumers. The word mycotoxin/aflatoxin was new to at least 50% of farmers in CR, ER, and BA. But farmers in AR (60%) and NR (93%) had previously heard the word mycotoxin/aflatoxin. However, about 93%, 60%, 60%, 27%, and 20% of farmers, respectively, in NR, AR, BA, ER, and CR had knowledge on effects of mycotoxin on humans and animals. Although most farmers in NR did not have formal education, they were very knowledgeable about the effects of mycotoxin on humans and animals. Therefore, having formal education does not depict knowledge of mycotoxin. In
Malaysia, Leong et al. (2012) similarly found no significant association linking farmers’ knowledge on aflatoxin to farmers’ education level. But contrary to the findings from
Suleiman et al. (2016) in Tanzania and Jolly et al. (2006) in Ghana. Thus, on a regular basis, farmers have to be educated on recent issues pertaining to the agriculture sector. In
NR, the extensive knowledge of farmer on the effects of mycotoxin on humans and animals was due to the immense efforts of their AEAs. At least 73% of farmers in all regions acknowledged the efforts of their AEAs. Most AEAs visit farmlands, and organize educational seminars for farmers, especially, the AEAs in NR.
5.3.6. Kinds of PHL and pest infestations
More than 67% of farmers in all five regions experienced PHL (fig. 5.6). PHL was predominantly caused by pest infestation (36% to 94% of farmers, fig. 5.7). Pest infestation was due mostly to insects, followed by rodents and then molds (fig. 5.8). Sitophilus zeamais
(maize weevil) was the only insect that infested the grain (table 5.2). The result indicates that S. zeamais is an important economic insect, and causes enormous damage to grain in
Ghana. Food security and income of farmers are reduced due to the damaging activities of
S. zeamais. The high maize weevil infestation could be attributed to delayed harvest and
147 poor storage facilities. It is important that farmers harvest grain on time to reduce field infestation, and should also use good storage facilities. The high percentage of farmers that experienced PHL is concomitant to challenges in grain storage found in developing countries. These challenges have been reported in many studies (Demissie et al., 2008;
FAO, 2011; Abass et al., 2014; Kaminski and Christiaensen, 2014; Affognon et al., 2015;
Suleiman et al., 2016). Molds infestation was not a major post-harvest challenge compared to rodents. The poor storage facilities did not prevent rodents’ attack, and PHL worsened.
5.4. Conclusions
Male maize farmers surpassed their female counterparts (%). Males cultivated larger acres of land compared to females. Since farmers cultivated smaller acres of land they are all categorized as smallholder farmers. Farmers used conventional (traditional) methods during harvesting, drying, shelling, and storage. A limited number of farmers had access to mechanized shelling machines. The conventional methods used resulted in high losses in grain quality and quantity. PHL was mainly due to maize weevils or rodents attack, but not molds. Besides the usage of synthetic insecticides, some farmers also use plant materials like seeds or leaves from pepper, basil, and neem plants to control maize weevils. We encourage farmers to desist from using synthetic insecticides, due to health and environmental implications associated with the misuse and misapplication of insecticides. Farmers’ knowledge of molds and mycotoxin effects was generally good. But was very encouraging in NR, kudos to AEAs, as at least 93% of farmers had no formal education. Farmers complained about the lack of financial loans and limited subsidies on farming inputs. Also, they entreated the government to provide price schemes for grain sale as the low predetermined prices offered by buyers or traders make them poorer.
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5.5. References
Abass, A. B., Ndunguru, G., Mamiro, P., Alenkhe, B., Mlingi, N., & Bekunda, M. (2014). Postharvest food losses in a maize-based farming system of semi-arid savannah area of Tanzania. Journal of Stored Products Research, 57, 49-57.
Adu, G. B., Abdulai, M. S., Alidu, H., Nutsugah, S. K., Buah, S. S., Kombiok, J. M.,… Etwire, P. M. (2014). Recommended Production Practices for Maize in Ghana. CSIR-AGRA Maize production guide, pp. 1-18.
Affognon, H., Mutungi, C., Sanginga, P., & Borgemeister, C. (2015). Unpacking postharvest losses in sub-Saharan Africa: A meta-analysis. World Development, 66, 49-68.
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Tables
Table 5.1. Regions and Districts in Which the Interviews Were Administered on Maize Farmers in Ghana.
Regions District/Municipality
1 2 3
Central Region (CR) Agona East Asikuma-Odoben- Gomoa East Brakwa
Eastern Region (ER) Akuapim North East Akim Kwahu East
Ashanti Region (AR) Asante Akim South Ejura-Sekyedumase Ejisu-Juaben
Brong Ahafo Region (BA) Kintampo North Nkoranza South Techiman
Northern Region (NR) Tolon Kumbungu Tamale
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Table 5.2. Demographic Data on Maize Farmers in Ghana.
Percentages Central Eastern Ashanti Brong Northern Parameter region region region Ahafo region region Males 93.0 73.0 73.0 80.0 73.0
Gender
Females 7.0 27.0 27.0 20.0 27.0
18-25 0.0 6.7 0.0 0.0 0.0 Age group (Years) 25-40 33.3 6.7 0.0 26.7 26.7
Over 40 66.7 86.7 100.0 73.3 73.3 None 0.0 0.0 13.3 46.7 86.7
Primary 6.7 26.7 26.7 20.0 13.3 Educational level Middle 6.7 20.0 6.7 6.7 0.0
Secondary 80.0 46.7 13.3 26.7 0.0
College 6.7 6.7 40.0 0.0 0.0
Table 5.3. Sizes of Farms Cultivated by Maize Farmers, and Different Means of Harvesting Maize Grain in Ghana.
Percentages Central Eastern Ashanti Brong Northern Parameter region region region Ahafo region region < 1 6.7 0.0 0.0 0.0 0.0
1 0.0 13.3 13.3 6.7 26.7 Area cultivated in acres 2-5 73.3 73.3 66.7 73.3 53.3
6-10 13.3 13.3 13.3 20.0 20.0
>10 6.7 0.0 6.7 0.0 0.0
Means of Hand 100.0 100.0 100.0 100.0 100.0 harvesting Mechanized 0.0 0.0 0.0 0.0 0.0
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Table 5.4. Pre-Harvest Losses and Associated Agents Experienced by Maize Farmers in Ghana.
Percentages
Parameter Central Eastern Ashanti Brong Northern region region region Ahafo region region Pre-harvest Yes 100.0 100.0 100.0 93.3 93.3 losses No 0.0 0.0 0.0 6.7 6.7
Birds 19.4 25.6 34.3 32.1 26.7
Agents of pre- Weather 19.4 23.3 25.7 28.6 6.7 harvest losses Insects 45.2 30.2 34.3 25.0 36.7
Rodents 16.0 20.9 5.7 14.3 30.0
< 1 60.0 46.7 66.7 80.0 0.0
Losses 2 6.7 13.3 20.0 20.0 80.0
> 3 33.3 40.0 13.3 0.0 20.0
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Table 5.5. Harvesting of Grains, Threshing, and Number of Months of Storing Maize Grain by Farmers in Ghana.
Percentages Central Eastern Ashanti Brong Northern Parameter region region region Ahafo region region < 4 days 66.7 60.0 33.3 33.3 60.0
Number of 1 week 33.3 20.0 20.0 66.7 40.0 days used in harvesting 2 weeks 0.0 20.0 26.7 0.0 0.0
> 2 weeks 0.0 0.0 20.0 0.0 0.0 < 5 6.7 33.3 6.7 13.3 0.0
Number of 5-15 46.7 53.4 33.3 40.0 46.7 bags per harvest (100 15-30 20.0 13.3 26.7 26.7 46.6 Kg) > 30 26.6 0.0 33.3 20.0 6.7 Hand 13.3 26.7 0.0 13.3 20.0
Mechanized 0.0 0.0 40.0 73.4 33.3
Methods used Improvised 0.0 6.7 13.3 0.0 0.0 in grain device threshing Beating 13.3 33.3 6.7 13.3 26.7
Beating & 73.4 33.3 40.0 0.0 20.0 hand < 1 month 0.0 0.0 0.0 6.7 0.0 Number of months of 3 months 13.3 20.0 33.3 33.3 13.3 grain storage (domestic use) 6 months 20.0 13.3 6.7 40.0 33.3
12 months 66.7 66.7 60.0 20.0 53.4
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Table 5.6. Post-Harvest Practices Used by Maize Farmers, and Weevil Infestations in Ghana.
Percentages Central Eastern Ashanti Brong Northern Parameter region region region Ahafo region region Insects Weevil 100.0 100.0 100.0 100.0 100.0 infection
No drying 26.7 6.7 0.0 13.3 0.0
Types of Sun drying 73.3 93.3 93.7 86.7 100.0 drying used Solar drying 0.0 0.0 6.3 0.0 0.0
Mechanical 0.0 0.0 0.0 0.0 0.0 drying Sorting of Yes 100.0 80.0 93.3 80.0 100.0 foreign materials No 0.0 20.0 6.7 20.0 0.0
Yes 100.0 80.0 93.3 80.0 100.0 Sorting of insects No 0.0 20.0 6.7 20.0 0.0
Sorting of Yes 86.7 66.7 93.3 80.0 100.0 broken seeds No 13.3 33.3 6.7 20.0 0.0 Hand 20.0 6.7 6.7 13.3 6.7
Winnowing 0.0 6.7 0.0 0.0 6.7 Methods used in Mechanical 0.0 0.0 0.0 0.0 0.0 sorting Hand and 80.0 66.6 86.6 66.7 86.6 Winnowing No sorting 0.0 20.0 6.7 20.0 0.0 Granary 33.3 56.3 20.0 0.0 0.0
Means of Silo 0.0 0.0 0.0 0.0 0.0 storage Polypropylene 13.3 37.5 60.0 86.7 100.0 bag Granary & 53.4 6.2 20.0 13.3 0.0 bags
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Table 5.7. Treatment of Shelled Maize Grain, and Handling of Damaged Ears by Maize Farmers in Ghana.
Percentages Central Eastern Ashanti Brong Northern Parameter region region region Ahafo region region Discard 37.4 36.8 9.5 15.0 33.3
Handling of Domestic use 16.7 5.3 33.3 30.0 0.0 damaged ears Use as feed 41.7 57.9 52.5 40.0 46.7
Sell 4.2 0.0 4.7 15.0 20.0
Usage of Yes 86.7 46.7 53.3 20.0 40.0 chemical treatment No 13.3 53.3 46.7 80.0 60.0
Yes 0.0 26.7 6.7 0.0 86.7 Usage of herbal No 100.0 73.3 93.3 100.0 13.3 treatment Insecticides 100.0 100.0 100.0 100.0 0.0
Chemical used Fungicides 0.0 0.0 0.0 0.0 0.0 in treatment Pesticides 0.0 0.0 0.0 0.0 0.0
Fumigants 0.0 0.0 0.0 0.0 100.0
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Table 5.8. The Use of Harvested Maize Grain, Knowledge of Maize Farmers on Mycotoxins, and Activities of AEAs in Ghana.
Percentages Central Eastern Ashanti Brong Northern Parameter region region region Ahafo region region Observation of fungi Yes 26.7 20.0 13.3 40.0 20.0 infestation No 73.3 80.0 86.7 60.0 80.0
Sale only 0.0 0.0 0.0 0.0 0.0
Consumption 0.0 0.0 6.7 13.3 0.0 Usage of harvested only grains Sale & 100.0 100.0 86.6 86.7 100.0 consumption Poultry feed 0.0 0.0 6.7 0.0 0.0
Knowledge of Yes 93.3 93.3 93.3 93.3 93.3 effects of moldy grains No 6.7 6.7 6.7 6.7 6.7
Previously heard of Yes 6.7 26.7 60.0 6.7 93.3 the word mycotoxins No 93.3 73.3 40.0 93.3 6.7
Yes 20.0 26.67 60.0 60.0 93.3 Aware of mycotoxins No 80.0 73.33 40.0 40.0 6.7 contamination in maize Yes 20.0 20.0 60.0 46.7 93.3 Aware of effects of mycotoxins on No 80.0 80.0 40.0 53.3 6.7 human and animals
Yes 80.0 73.3 80.0 86.7 100.0 Acknowledge efforts of extension No 20.0 26.7 20.0 13.3 0.0 agents 1 per month 8.3 0.0 16.7 0.0 0.0 Number of times visited by extension agents 2 per month 0.0 0.0 16.7 15.4 6.7
Many times 91.7 100.0 66.6 84.6 93.3
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Figures
Figure 5.1. Improvised Corn Shelling Device, and a Plastic Gallon for the Hermetic Storage of Maize Grain in Ghana.
Figure 5.2. Locally Made Shelling Machine Used by Some Farmers to Shell Maize in the Northern Region of Ghana.
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Figure 5.3. Shelled Grain Being Dried on the Bare Floor in Brong Ahafo Region, Ghana.
160
a
b
Figure 5.4. Traditional Granaries for Maize Storage Used by Some Farmers in Ghana.
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Figure 5.5. Basil Herb Plant Used for Treating Maize Grain by Some Farmers in Ghana.
162
120
100
80
Percent 60
40
20
0 Yes No Yes No Yes No Yes No Yes No Eastern Central Ashanti Brong Ahafo Northern Post-harvest losses
Figure 5.6. The Percent of Maize Farmers that Observed Post-Harvest Losses in Maize Grain in Ghana.
163
100
90
80
70
60
50
40 Percent Percent losses of
30
20
10
0 P LS PS PW ID P LS PS PW ID P LS PS PW ID P LS PS PW ID P LS PS PW ID Eastern Central Ashanti Brong Ahafo Northern Different kinds of post-harvest losses
P= pest infestation, LS= lack of storage facility, PS = poor storage facility, PW= poor weather, ID= improper drying.
Figure 5.7. Different Kinds of Post-Harvest Losses Observed by Maize Farmers in Ghana.
164
80
70
60
50
40
30 Percent Percent loss of
20
10
0
Birds Birds Birds Birds Birds
mold mold mold mold mold
Insects Insects Insects Insects Insects
rodents rodents rodents rodents rodents Eastern Central Ashanti Brong Ahafo Northern
The different kinds of pest infestations
Figure 5.8. The Losses (%) in Maize Grain Due to the Different Kinds of Pest Infestations in Ghana.
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Appendix 5.1. Questionnaire for Preharvest and Postharvest Maize Grain Losses, Harvest and Storage Practices, and Farmers' Knowledge of Mycotoxins.
A: General information
1. Date…………………………………………………… Region…………………………………………… 2. Name of village…………………………………………………………………… 3. Name of District…………………………………………………………………. 4. Name of interviewee……………………………………………………………… 5. Gender (a) Male [ ] (b) Female [ ] 6. Age (a) under 18 [ ] (b) 18-25 [ ] (c) 25-40 (d) over 40 7. Education level ……………………………………………………………………. (0 = none, 1 = Primary, 2 = Secondary, 3 = College, 4 = none, 5 = other………….) 8. What type of activity are you involved in...... (1 = farming, 2 = trader, 3 = consumer, 4 = both 1, 2, & 3, 5 = other……….)
B: Pre-Harvest losses
9. Do you observe any losses before harvest...... (1 = Yes, 2 = No) 10. What are the losses………………………………………………………………. (1 = birds damage, 2 = weather, 3 = insects, 4 = Rodents, 5 = other……………) 11. Per your estimation what is the quantity of the losses (1= less than 1%, 2 = 2%, 3 = above 5%).
C: Information on Farmers
12. Total area cultivated (Ha) (a) below 5 [ ] (b) 5-10 [ ] (c) 10-50 [ ] (d) above 50 [ ] 13. How is the harvesting done………… (1 = Hand, 2 = Combine, 3 = Other…….) 14. Days used in the harvesting……………………………………………………. (1 = less than 4 days, 2 = one week, 3 = two weeks, 4 = more than 2 weeks) 15. Bags or kg of maize harvested last season ……………...... 16. How is the shelling/threshing done…………………………………………….. (1 = hand, 2 = mechanized, 3 = improvised device, 4 = Beating, 5 = others………) 17. Any losses per harvested (if any)...... (1 = Yes, 2 = No) 18. What are the main reasons for post-harvest loses...... (1 = Pest infestation, 2 = lack of storage, 3 = Poor storage, 4 = Poor weather, 5 = improper drying, 6 = other ...... )
If the answer in (18) is 1 go to Question 19
19. What types of pest infestation...... ? (1 = insects, 2 = mold, 3 = rodent/mice, 4 = birds, 5 = other …….....)
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If the answer in (19) is 1 go to Question 20
20. What types of insect...... ? (1 = maize weevils, 2 = larger grain borer, 3 = other ………………….) 21. An average number of months maize is stored …………...………...... (1 = less than 1 month, 2 = three months, 3 = six months, 4 = one year, 5 = other…..) 22. How is the maize grain dried...... ? (1= No drying, 2= sun drying, 3 = solar drying, 4 = mechanical drying, 5 = other....) 23. After harvesting do you sort out foreign materials (e.g.: other seeds, ears, stones………………………… (1 = Yes, 2 = No) 24. After harvesting do you sort out infected/diseased seeds………...(1 = Yes, 2 = No) 25. After harvesting do you sort out broken seeds……………………(1 = Yes, 2 = No) 26. What method do you use for the sorting……………………………………… (1 = hand picking, 2 = winnowing, 3 = mechanical, 4 = other…………..……) 27. What do you do with the damaged maize ears……………………………….? (1= throw away, 2= domestic consumption, 3= animal feeds, 4= sell, 5 = other…) 28. At what level do you discard maize grain...... ? (Picture: 1 = when show sign of mold growth, 2 = when showing a clear sign of mold growth, 3 = when is total moldy, 4 = not discard, 5 = other ………) 29. What methods of discard ……………………………………………………? (1 = used as animal feeds, 2 = burning, 3 = burial, 4 = left in the field, 5 = other…) 30. How do you store the grains after harvest……………………………… (1 = traditional granary, 2 = silos, 3 = bags, 4 = rented facility, 5 = other ……) 31. Are the grains treated before storage………………………………………… (1 = insecticides, 2 = fungicides, 3 = pesticides, 4 = fumigants, 5 = other) 32. Do you have any knowledge about the effect of moldy maize…? (1 = Yes, 2 = No) 33. Have you previously heard of the word mycotoxins (aflatoxins)? (1 = Yes, 2 = No) 34. Are you aware of mycotoxins contamination in maize?………(1 = Yes, 2 = No) 35. Are you aware of the effects of mycotoxins on human and animals?...... (1 = Yes, 2 = No) 36. In your view, where in the post-harvest maize value chain do the major losses occur? (1 = transport from field to home, 2 = drying, 3 = shelling, 4 = storage, 5 = transport to market, 6 = during marketing, 7 = other ………….…………………) 37. Do you produce for consumption or for sale…………...... (1 = Yes, 2 = No, 3 = Both, 4 = Others……………..) 38. Are you visited by extension agents……………………(1 = Yes, 2 = No) 39. How frequently do they visit your farm……..... (1 = once per year, 2 = twice per year, 3 = thrice per year, 4 = other …………….…...) 40. Are the services of the extension agents useful/helpful to you…..(1 = Yes, 2 = No) 41. If 40 is NO, then what do you expect from these agents……………………… 42. What services do the agents provide to you……………………………………. 43. Are you willing to offer your farm for my research studies next year...……. (1 = Yes, 2 = No).
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CHAPTER 6. INVESTIGATING THE PERIODIC PHYSICAL DISTURBANCE METHOD IN GHANA TO CONTROL ADULT SITOPHILUS ZEAMAIS
Modified from a manuscript to be submitted to the Applied Engineering in Agriculture
Abstract
Maize rates at least 50% of Ghana’s cereal cultivation, and an estimated 18% of
PHL. Sitophilus zeamais is an important cosmopolitan pest and the most detrimental insect of stored maize. Physical disturbance technique is based on the application of force or activities that change the environment in the storage container to make insects unfavorable.
The aim was to investigate the efficacy of the periodic physical disturbance method on S. zeamais mortality. The potential adoption of the technology by farmers in Ghana was also considered so as to prevent the reliance on synthetic insecticides. Eight dedicated farmers were supplied with nine plastic buckets (20 L) and live S. zeamais. Each bucket was loaded with 10 kg of white maize grain, and 1,000 S. zeamais in a non-hermetic condition. Each farmer applied 2.5 minutes of physical disturbance to the six treatment buckets twice a day for 30, 60 and 90 days. Two treatment buckets and one control bucket were picked at 30,
60 and 90 days for further analysis. About 2.5 kg grain was sampled from each homogenized bucket and the numbers of dead and live S. zeamais were counted. The percent mortality data set was analyzed with ANOVA. The physical disturbance method did not result in any significant mortality of S. zeamais. The failure of the method could be due to human error or the large number of S. zeamais used inundated the method, or the high temperature, RH and grain MC favored the growth and development of S. zeamais.
Despite the failure of the method in causing S. zeamais mortality, the grain quality was maintained in the disturbed buckets. In the undisturbed buckets, grain was moldy, “caked”, and discolored.
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Keywords: Periodic physical disturbance; Ghana; maize grain; S. zeamais; mortality.
6.1. Introduction
Maize rates at least 50% of Ghana’s cereal cultivation and it is vastly consumed.
Ghana loses about 18% of the yearly maize production to PHL (ISSER, 2017). Maize is cultivated immensely in rain-fed conditions by smallholder farmers. The following statistics on maize production in Ghana was gathered in 2016. The harvested area was 883,
031 ha and the average rate of annual growth is 4.04%. The yield area was 1,950 kg/ha
(789 kg/ac) which grows annually at an average rate of 2.91%. Importantly, the production quantity in Ghana was 1,721,910 Mg, and the annual average rate of growth is 8.93%
(Knoema, 2017). The quantity of maize produced in Ghana compared to most SSA nations is low. In the poultry and livestock industry, and to accomplish food security maize is considered a crucial crop. About 318,514 Mg of maize in Ghana is lost yearly due to PHL which represents about 18% of the country’s annual maize production (PrimeNewsGhana,
2017). The losses are mostly caused by molds, rodents, improper handling, lack of storage facilities, and S. zeamais.
S. zeamais is an economically important cosmopolitan pest (Demissie et al., 2008), and the most detrimental insect of maize grain (Danho and Haubruge, 2003). The best quality of grain is at harvest, and therefore preserving grain at storage cannot improve the grain quality better than the quality at harvest. According to Bern et al. (2013), the quality of grain at harvest cannot be improved by preservation, and deterioration cannot completely be stopped but can be decelerated. Combination of factors like moisture, temperature, and oxygen can commence degradation in stored grain. However, the determining factors controlling the biochemical oxidation of stored grain are MC and temperature.
169
The utilization of drying, refrigeration, ionizing radiation, mechanical isolation, and chemical treatment are the most common methods used in preserving maize grain
(Bern et al., 2013). However, a physical disturbance technique is also considered an efficient grain preservation method. The physical disturbance techniques are based on the application of force or activities that manipulate the storage environment to cause unfavorable conditions to pests (Banks, 1986; Paliwal et al., 1999). The physical disturbance technique used in controlling grain weevils has been around for decades
(Banks, 1986). The effect of bean tumbling to control bean bruchid during storage was investigated by Quentin et al. (1991). According to the outcome of that research, the physical disturbance was able to cause the demise of bean weevils. The mortality was attributed to the weevils exhausting considerable energy without gaining access to the cotyledon (starvation).
Worth noting are the recent research works carried out to control S. zeamais in stored maize (Bern et al., 2016; Suleiman et al., 2016). Suleiman et al. (2016) reported an overall percent mortality of 88%, 96%, and 98% respectively at 30, 60, and 90 days of storage. According to Bern et al. (2016), although the live numbers of S. zeamais in the disturbed containers were significantly lower (ca. 46% lower) at day 40, about 93% S. zeamais mortality was achieved at 160 days in the disturbed containers. The high S. zeamais mortality (%) achieved when physical disturbance technique is used necessitated the trial of the technology in Ghana. This technology can replace the application of synthetic insecticides which have detrimental impacts on the environment and humans
(Phillips and Throne, 2010). The physical disturbance method is very simple, affordable,
170 and safe in controlling stored-product insect pests in grain facilities (White et al., 1997;
Suleiman et al., 2016).
This experiment involved farmers, researchers and extension officers. Farmers were included because they are the immediate beneficiaries of the technology. The aim of this study was to investigate the efficacy of the periodic physical disturbance method on S. zeamais mortality. The potential adoption of the technology by farmers in Ghana was also considered to prevent the reliance on synthetic insecticides.
6.2. Materials and Methods
6.2.1. Research site and experimental design
The Tontro town in Ghana was the experimental site. This town is one of the major maize production towns in Ghana. Eight dedicated farmers were chosen, and each farmer was supplied with nine plastic buckets (20 L) and live S. zeamais. The S. zeamais were cultured in a laboratory of the Radiation Technology Centre, Ghana Atomic Energy
Commission. The same variety of white maize grain was purchased from the individual study participants. Each bucket was loaded with 10 kg of grain which was about 50% of the bucket’s full level. The MC of the grain used was 14.7±0.4%, which was measured
(triplicate) with DICKEY-JOHN (Auburn, IL) mini GAC® plus hand-held Moisture Tester
(Minigac1P). The number of S. zeamais loaded was 1,000 per each bucket. S. zeamais weighing 36.72 g was estimated to be equalling 1,000 in number (Bbosa et al., 2017). The grain MC and the number of S. zeamais used depicted the conditions that farmers experience. A preliminary study showed that 1 kg of grain was infested with 100±8 of S. zeamais. Holes were created in the bucket covers for gaseous exchange (non-hermetic conditions). These holes were then covered with screens to prevent the escape of the S. zeamais. The buckets were then kept in rooms at a temperature of 27±5oC. On each day for
171
30, 60 and 90 days, each farmer applied 2.5 minutes of physical disturbance to the six treatment buckets in the morning and evening. The remaining three buckets (per farmer) served as the control (undisturbed). Two treatment buckets and one control bucket were picked on days 30, 60 and 90 for further analysis. About 2.5 kg grain was sampled from each homogenized bucket, and the numbers of dead and live S. zeamais were visually counted. The sampling was based on the quartering technique after the grain had been spread and homogenized on a dry clean rubber sheet (Schuler et al., 2014; Suleiman et al.,
2016). The percent mortality of S. zeamais was calculated based on the equation by
Omotoso and Oso (2005).
Number of dead insects Mortality (%) = ∗ 100 …………………………………… (6.1). Total number of insects
6.2.2. Data analysis
The data set was analyzed with ANOVA, and means with significant differences
(P < 0.05) were separated with Tukey-Kramer HSD.
6.3. Results
Table 6.1 shows the numbers of S. zeamais that were alive and dead, and also the percent mortality at 30, 60, and 90 days. In table 6.2, there was no significant difference in mean mortality of S. zeamais between the disturbed and the undisturbed grain at 30, 60 and
90 days. This stipulates that S. zeamais mortality in the disturbed and undisturbed buckets were similar irrespective of the days of storage. Percent mortality in the undisturbed buckets at 90 days happened to be highest although not significant. Mortality was expected to increase correspondingly with the increasing days of storage, surprisingly that did not happen, and the lowest mortality was at 60 days. In table 6.3, there was no significant difference in mortality between the disturbed buckets at 30, 60 and 90 days. In contrast,
172 mortality in the undisturbed buckets at 90 days was significantly high compared to the 30 and 60 days.
In table 6.4, S. zeamais mortality in the disturbed buckets at 30, 60 and 90 days based on individual farmers were not significant except for the sixth farmer. The sixth farmer recorded significantly high mortality of S. zeamais, but it did not follow any particular pattern.
6.4. Discussion
Percent mortality of S. zeamais although was not significant between the disturbed and undisturbed at 30, 60 and 90 days, but at 30 days the result was not unexpected.
Because at 30 days, the effect of the applied force might not have substantially manipulated the internal storage environment in the buckets. Hence, the S. zeamais comfortably survived, and mortality was low. Optimistically, obtaining adequate unfavorable internal changes in the buckets might have demanded a physical disturbance of quite a few more days above the 30 days. Nonetheless, some findings support the results of this study. Bern et al. (2016) reported no significant difference in S. zeamais mortality between the disturbed and undisturbed at 40 days when maize grain of 13.6% MC was used. In contrast,
Suleiman et al. (2016) recorded significant S. zeamais mortality between the disturbed and undisturbed maize grain even at 30 days.
The non-significant mortality of S. zeamais between the disturbed and undisturbed at 60 and 90 days was unanticipated but not unrealistic. There is no specific reason to attribute to the unanticipated results, however, speculation that human error might have been the cause cannot be ignored. The reason is that the sixth farmer happened to obtain a significant difference between days of treatment although this did not follow any specific pattern. It might be that, farmers did not apply the quantum of force that could have
173 effectively resulted in a significant S. zeamais mortality. According to the FAO (2017), to attain high weevil mortality demands sufficient violent disturbance and small grain quantity. However, the extent or quantum of the sufficient violent disturbance was not specified. The violent disturbance might be the reason for the high mortality of bean bruchid weevils as they were dislodged from accessing nutrient from the grain (Quentin et al., 1991). Quentin et al. (1991) attributed the 97% mortality to the inability of the first instar larvae to penetrate through the testa of the grain in 24 hour period due to the disturbance. Suleiman et al. (2016) surmised that S. zeamais mortality was also due to starvation. That speculation notwithstanding, mortality of S. zeamais could be ascribed to many conditions. Joffe and Clarke (1963) disclosed that S. oryzae mortality depended on the type, timing, and frequency of disturbance. But the most vulnerable stage of the S. oryzae to physical disturbance was the immature and adult stages. Hence, the contrary findings of this study to other recent findings from Bern et al. (2016) and Suleiman et al.
(2016) could be due to some of the factors outlined above.
Throne (1995) indicated that insect mortality varies with age, O2 concentration, temperature and MC, and the number of larvae per kernel. Importantly, the oviposition and feeding behavior of insects likely affect their status and control (FAO, 2017). In this study, the 1,000 S. zeamais per bucket might have been too large a number to mortalize using physical disturbance. Thus, the physical disturbance applied was not proportionally effective to cause appreciable S. zeamais mortality. In comparison to this study, many studies that achieved insect mortality even at 30 days did not use large numbers of S. zeamais (Suleiman et al., 2016 used 174 grain, and the high RH (76-92%) might have been the cause of the increased grain MC. The increased grain MC was conducive for fungal development and spoilage, especially in the undisturbed buckets. Low grain MC results in high S. zeamais mortality caused by desiccation, a condition due to the loss of body water (Navarro, 1978). Hare (2017) suggested that grain MC has to be 12.5% w/w to have safe storage. Despite the absence of molds in the disturbed buckets, the high grain MC, the large number of S. zeamais, and high temperature (27±5oC) and RH (84±8%) might be the cause of the insignificant S. zeamais mortality. In such a storage condition insects’ fecundity tends to increase. Above 20oC, the population growth of insects increases with increasing temperature and MC (Throne, 1995). The summation of RH (%) and temperature (oF) was above 100%, and this constituted an extremely unsafe storage condition that required precautionary measures (Copeland and McDonald, 1999; Bewley et al., 2013). The farmers failed to clean the grain after shelling, and many foreign materials were found in grain. The lack of proper threshing and sorting methods resulted in a huge amount of foreign materials (broken ears and seeds, chaff, dust, debris, and moldy grain) in the stored grain. The foreign materials might have caused hot spots in grain, especially beneath the grain surface in the undisturbed buckets due to limited aeration. Hot spots increase grain temperature which enhances S. zeamais growth and survival. The absence of molds in the disturbed buckets could be asserted to the physical disturbance as grain happened to be aerated due to the movement of grain. Unlike the disturbed grain, the undisturbed grain was “caked”, discolored and moldy and might be due to the hot spots. Therefore, the 51% S. zeamais mortality in the undisturbed at 90 days could be attributed to the fungi effect as a large number of the S. zeamais were trapped in the “cake”. Alternatively, the foreign 175 materials might have impeded airflow beneath the grain surface in the undisturbed buckets and denying S. zeamais of oxygen. To have safe grain storage, low MC grain should be cleaned to maintain quality (Uthayakumaran and Wrigley, 2017). 6.5. Conclusions Generally, the physical disturbance method did not significantly cause S. zeamais mortality. Although the cause of the failure of the technique in this study cannot be pinpointed, it can be speculated to be due to human error (thus, the applied physical disturbance was not efficient enough to cause mortality) or the large number of S. zeamais used inundated the disturbance technique, or the high temperature, RH and grain MC favored the growth and development of S. zeamais. A combination of the outlined factors could be the reason for the failure. Noteworthy, despite the failure of the physical disturbance in causing S. zeamais mortality, the quality of grain in the disturbed buckets was maintained. The grain in the undisturbed was moldy, “caked”, and discolored. 6.6. References Banks, H. J. (1986). Impact, physical removal and exclusion for insect control in stored products. Proceedings of the 4th International Work-Conference Store Products Protection, pp. 165-184. Tel Aviv, Israel. Bbosa, D., Brumm, T. J., Bern, C. J., Rosentrater, K. A., & Raman, D. R. (2017). Evaluation of hermetic maize storage in 208 liters (55 gals) steel barrels for smallholder farmers. ASABE, 60(3), 981-987. http://lib.dr.iastate.edu/abe_eng_pubs/818 Bern, C. J., Brumm, T. J., & Hurburgh, C. R. (2013). Grain quality. In: Managing grain after harvest. Iowa State University bookstore, Ames, Iowa. Bern C. J., Bbosa, D., Brumm, T. J., Rosentrater, K. A., & Raman, D. R. (2016). Controlling weevils in maize by means of physical disturbance. International Conference on Agricultural and Food Engineering. Kaula Lumpur, Malasia: CAFEi2016-78. Retrieved on 11 January 2018. 176 Bewley, J. D., Bradford, K. J., Hilhorst, H. W. M., & Nonogaki, H. (2013). Seeds: Physiology of development, germination, and dormancy (3rd Ed). Publisher’ Graphics LLC. Springer New York-Heidelberg Dordrecht London. pp. 351. Copeland, L. O., & McDonald, M. B. (1999). Principles of seed science and technology. Kluwer Academic Publishers Group, Dordrecht. Demissie, G., Tefera, T., & Tadesse, A. (2008). Efficacy of SilicoSec, filter cake and wood ash against the maize weevil, Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) on three maize genotypes. J. Stored Prod. Res., 44, 227-231. FAO. (2017). Grain storage techniques - Evolution and trends in developing countries. Corporate document repository. http://www.fao.org/docrep/t1838e/t1838e1f.htm. Retrieved on 7 August 2017. Hare, R. (2017). Durum wheat: Grain-quality characteristics and management of quality requirements: In C. Wrigley, I. Batey & D. Miskelly (Ed.), Cereal grains: Assessing and managing quality (2nd ed., pp. 142). Kidlington, United Kingdom: Woodhead Publishing (Elsevier). ISSER. (2017). Improving food security by reducing the maize yield gap in Ghana. Institute of Statistical, Social and Economic Research, College of Humanities, University of Ghana. Policy brief: Vol. 8, Oct. 2017. Retrieved on 19 June 2017. Joffe, A., & Clarke, B. (1963). The effect of physical disturbance or “turning” of stored maize on the development of insect infestations. Laboratory studies with Sitophilus oryzae (L.). South African Journal of Agricultural Science 6, 65-84. Knoema. (2017). Production Statistics - Crops, Crops Processed. Friday, 15 December 2017 https://knoema.com/FAOPRDSC2017/production-statistics-crops-crops processed?country=1000790-ghana&item=1000840-maize. Retrieved on 19 February 2018. Navarro, S. (1978). The effect of low oxygen tensions on three stored-product insect pest. Phytoparasitica, 6, 51-58. Omotoso, O. T., & Oso, A. A. (2005). Insecticidal and insect productivity reduction capacities of Aloe vera and Bryophyllum pinnatum on Tribolium castaneum (Herbst). Afr. J. Appl. Zool. Environ. Bio., 7, 95-100. Paliwal, J., Jayas, D. S., White, N. D. G., & Muir, W. E. (1999). Effect of pneumatic conveying of wheat on mortality of insects. Appl. Eng. Agric., 15, 65–68. Phillips, T. W., & Throne, J. E. (2010). Biorational approaches to managing stored-product insects. Annu. Rev. Entomol., 55, 375–97. 177 PrimeNewsGhana. (2017). Ghana loses 18% of annual maize production to post-harvest losses. November 16, 2017. https://www.primenewsghana.com/business/ghana- loses-300-000-tons-of-maize-annually-to-post-harvest-losses.html. Retrieved on 19 February 2018. Quentin, M. E., Spencer, J. L., & Miller, J. R. (1991). Bean tumbling as a control measure for the common bean weevil, Acanthoscelides obtectus. Entomol. Exp. Appl., 60, 105–109. Schuler, N. J., Bern, C. J., Loy, D. D., Brumm, T. J., & Strohbehn, D. R. (2014). Mixing beef feed rotations containing distillers’ wet grains. Appl. Eng. Agric., 30, 199–204. Suleiman, R., Rosentrater, K. A., & Chove, B. (2016). Periodic physical disturbance: An alternative method for controlling Sitophilus zeamais (maize weevil) infestation. Insects, 7(51), 1-8. Throne, J. E. (1995). Computer modeling of population dynamics of stored-product pests. In: D. S. Jayas, N. D. G. White & W. E. Muir (Eds.), Stored-grain ecosystems (pp 178). New York: Marcel Dekker. Uthayakumaran, S., & Wrigley, C. (2017). Wheat: grain-quality characteristics and management of quality requirements. In: C. Wrigley, I. Batey & D. Miskelly (Eds.), Cereal grains: assessing and managing quality (2nd ed., pp. 121). Kidlington, United Kingdom: Woodhead Publishing (Elsevier). White, N. D., Jayas, D. S., & Demianyk, C. J. (1997). Movement of grain to control stored- product insects and mites. Phytoprotection, 78, 75–84. 178 Tables 179 Table 6.2. Comparing the Percent Mortality of S. zeamais between the Disturbed and Undisturbed Samples at 30, 60 and 90 Days of Grain Storage. Day 30 Day 60 Day 90 Disturbed 42.2 ± 11.7 32.2 ± 10.6 44.2 ± 18.2 Undisturbed 40.3 ± 5.1 31.1 ± 10.9 51.4 ± 14.6 P-values 0.67 0.83 0.35 Mean ± standard deviation in the same column are not significantly different at P < 0.05. Table 6.3. Comparing the Percent Mortality of S. zeamais in the Disturbed or Undisturbed Samples at 30, 60 and 90 Days of Grain Storage. Disturbed Undisturbed Day 30 42.2±11.7 40.3±5.1b Day 60 32.2±10.6 31.1±10.9b Day 90 44.2±18.2 51.4±14.6a P-values 0.05 <0.0001 Mean ± standard deviation in the same column with different connected letters are significantly different at P < 0.05. 180 Table 6.4. Comparing the Percent Mortality of S. zeamais in the Disturbed Samples per Each Farmer at 30, 60 and 90 Days of Grain Storage. Farmers Days 1 2 3 4 5 6 7 8 30 38.0± 38.2± 48.5± 60.3± 42.6± 46.2± 38.1± 25.5± 1.3 1.8 10.1 13.6 12.7 1.2ab 12.4 4.0 60 37.3± 28.4± 30.6± 42.8± 51.2± 27.2± 22.5± 27.0± 2.8 6.8 12.8 7.9 4.2 4.9b 3.5 16.9 90 37.8± 39.7± 34.8± 31.3± 47.2± 83.9± 40.3± 38.9± 3.3 17.7 5.9 14.2 9.5 14.8a 15.0 0.5 p 0.95 0.59 0.32 0.20 0.83 0.02* 0.36 0.45 Mean ± standard deviation in the same column with different connected letters are significantly different at P < 0.05. 181 CHAPTER 7. ASSESSING THE EFFICACY OF HERMETIC STORAGE BAGS AGAINST WOVEN POLYPROPYLENE BAGS BY FARMERS IN GHANA Modified from a manuscript to be submitted to the Applied Engineering in Agriculture Abstract The main insect that deteriorates stored maize grain in the tropics is Sitophilus zeamais. S. zeamais can inflict serious damage to maize in storage leading to about 20% to 50% or more losses within 3 to 6 months of storage. Hermetic bags reduce grain losses effectively compared to the woven polypropylene bags under similar storage conditions. The objective was to help farmers in Ghana tests and ascertain the benefits of storing maize grain using GrainPro bags in contrast to woven polypropylene bags. Eight farmers were provided with three bags each of GrainPro and woven polypropylene bags. The 25 kg bags were loaded with 20 kg of naturally S. zeamais infested white maize grain. The sealed bags were stored for 6 months at 28±6oC. A representative sample of 1 kg was taken for further analysis from each homogenized bag. Percentages were calculated, and ANOVA was done for all the measured quality parameters. All the woven polypropylene bags were damaged but no GrainPro bags were damaged. The percentage of damaged grain in woven polypropylene bags was between 91.9% and 94.4%, and from 0.2% to 0.7% in GrainPro bags. Zero gram and 48.0 to 73.7 g of fines were produced in GrainPro and woven polypropylene bags respectively. A 100.0% S. zeamais mortality was achieved in GrainPro bags compared to less than 10.0% in woven polypropylene bags. GrainPro bags proved a better alternative to woven polypropylene bags, they are reusable (product life of 2 years), and hence cost-effective to farmers. Keywords: Maize grain; GrainPro bags; polypropylene bags; hermetic storage; Sitophilus zeamais. 182 7.1. Introduction Some controllable factors limit the production of maize in SSA and many other developing nations. In developing countries, insects and rodents cause huge losses in quality and quantity of stored grain (Rajendran and Sriranjini, 2008; Kamanula et al., 2010). The main insect that damages stored maize grain in the tropics is Sitophilus zeamais (Rugumamu, 2012). S. zeamais can inflict serious damage to maize grain that may lead to 20-50% or more losses when grain is stored for about 6 months (Mulungu et al., 2007; World Bank, 2011). Grain weight losses contribute largely to PHL (Kumar and Kalita, 2017). Having effective grain storage systems can drastically reduce food losses and improve the livelihood of smallholder farmers. Preventing pests’ infestation is essential during storage to maintain food quality, make food accessible, and to stabilize food security and income security of farmers (Boxall, 2001). One of the available options to control pest’s infestation in SSA is to use synthetic pesticides. However, synthetic pesticides are expensive, may be adulterated or not readily available in markets (Njoroge et al., 2014). Also, synthetic chemicals may be ineffective and have detrimental health and environmental effects (Addo et al., 2002). The worse of it all is that the increased use has resulted in resistance among certain species that has reduced the effectiveness of the chemicals (Benhalima et al., 2004; Collins, 2006). Hermetic containers and bags are appropriate and effective alternatives to synthetic pesticides. Another alternative to chemical use during grain storage is the hermetic metal bin. It is a galvanized metal sheet made into an airtight storage silo. A hermetic metal silo is effective against rodents, birds, molds, and insects to reduce grain losses (Tefera et al., 2011; SDC, 2017). Although metal silo is effective in controlling insects or pests’ infestations to improve food security and incomes of farmers, it is expensive to buy or 183 manufacture (Gitonga et al., 2013; De Groote et al., 2013). Hermetic bags including the PICS bags, Super Grain Bags, and GrainPro bags are all effective at controlling insects and are less costly. Comparatively, these bags reduce grain losses better than woven polypropylene bags when storage conditions are similar (Baoua et al., 2013). These bags are extensively utilized in many parts of Africa because they are effective, simple, low cost, durable, easy to produce, and require small storage space (Baoua et al., 2012). However, hermetic bags have some disadvantages including high susceptibility to physical damages. These damages could be punctures from sharp end objects, abrasions, and perforations by insects and rodents (De Groote et al., 2013; García- Lara et al., 2013). These bags can also burst during transportation. The bags then lose their usefulness when they get damaged and further add extra cost to farmers. Hermetic conditions work on a simple principle involving oxygen and carbon dioxide concentrations. Low oxygen concentration is created in these bags or containers that reduce insect development (Murdock et al., 2012; Suleiman et al., 2018). Within 1 month of storage, about 98% mortality of all insect pests can be achieved which reduces damage to grain by insects (Baoua et al., 2012). In a 6 months’ storage study of maize grain, Bauoa et al. (2012) found that hermetic bags give protection to grain against insect infestations without any loss in quality. Similarly, PICS bags maintained grain quality more effectively compared to woven polypropylene bags (Williams et al., 2017). The use of woven polypropylene bags in developing countries to store grain cannot wholly be condemned or eliminated. This is because they are readily available in the markets and less expensive compared to hermetic bags or silos. However, they are used with caution. To effectively control insects/pests, insecticides/pesticides such as 184 Malathion, Deltamethrin, and Actellic super, and Phosphine (fumigant) are used. Rodents can be controlled with poison baits (Naik and Kaushik, 2017) and traps in both scenarios of using woven polypropylene and hermetic bags if the storeroom is not rodent-proof. With the intention to reduce or avoid the overreliance on synthetic chemicals based on their toxicity and expensiveness, farmers have been advised to accept and use hermetic technology although relatively new in Ghana. Hence, farmers were allowed to participate in the use of GrainPro bags (hermetic bags) to appreciate the significance of hermetic technology. The objective was to help farmers in Ghana tests and ascertain the essence of storing maize grain in hermetic bags (GrainPro bags) in comparison to the woven polypropylene bags. 7.2. Materials and Methods 7.2.1. Experimental set-up Eight farmers were selected for this experiment. Farmers were selected from Tontro in the Eastern region of Ghana where the study happened. Each farmer was provided with six bags, three each of GrainPro bags (hermetic) and woven polypropylene bags (non- hermetic). Both types of bags had 25 kg storage capacity, and the GrainPro bag had a single layer (78±10% thickness) of high strength PE with a barrier layer and 2 track PE zipper (GP, 2018). Similarly, the polypropylene bag was single-layered. The white maize grain used in the study was obtained from the farmers, and the grain had a natural S. zeamais infestation (Baoua et al., 2014). Damaged grain (grain with holes, and broken grain), foreign materials, and dead S. zeamais were sorted and discarded prior to loading the bags. Handpicking was the mode of sorting and was done by spreading small portions of the grain on a white cloth. In a preliminary count, the number of S. zeamais infestation per 1 kg of grain was estimated to be 67±14. The GrainPro bags were hermetically sealed with 185 the 2 track PE zipper based on the manufacturer’s instructions. The polypropylene bags were firmly tied to prevent the escape of the S. zeamais. The grain used had an average MC of 14.0±0.5%, which was measured (triplicate) with DICKEY-JOHN (Auburn, IL) mini GAC® plus hand-held Moisture Tester (Minigac1P). The individual farmers stored the stacked bags at 28±6oC. After 6 months, the bags were opened, and the content of each bag was homogenized. Homogenization was done by spreading and gently mixing the content of an opened bag on a clean rubber sheet. A representative sample sum of 1 kg (USDA, 2013) was taken from different sites of the homogenized bag for further analysis. A sieve of size 0.99 mm (99*10-5 m) was used to separate the powder by retaining the S. zeamais and grain. The mass of powder produced was measured (g/1 kg of the sample). The retained S. zeamais and grain were used to determine the percentage of damaged grain (i.e. by weight, grain with holes or devoured endosperm and/or germ caused by S. zeamais), grain weight loss (%), and percent mortality of S. zeamais. The percentage of grain weight loss was determined by using the count and weigh method (equation 3.1) developed by Adams and Schulten (1978). The percentage of storage bags damaged (visible holes created in bags due to the frequent movements outside and into the bags by S. zeamais) was also calculated. The damaged bag was determined based on the physical observation of holes in the bags. 7.2.2. Data analysis After calculating the percentages, the data set was graphed or tabulated and analyzed with ANOVA. Tukey-Kramer HSD was used to separate significant means (p < 0.05). 186 7.3. Results Although eight farmers were used in the study, data from seven farmers were analyzed because there was unexpected damage to the experimental units of one farmer. As shown in figure 7.5b, two of the GrainPro bags were damaged by mice during storage. Figure 7.1 shows the percent number of storage bags that were damaged by S. zeamais. The S. zeamais damaged (holes created due to frequent in and out movements) all the woven polypropylene bags used. All the GrainPro bags used were resilient to S. zeamais attack, and hence no damaged bag was recorded. In figure 7.2, the percentage of grain damaged by S. zeamais was recorded. The damages consisted of holes created in the kernels, and consumption of the entire endosperm and germ (embryo) of the kernel. In most cases, only the grain bran and hull remained. The percentage of damaged grain in the woven polypropylene bags ranged between 91.9% and 94.4%. Compared to damaged grain in the GrainPro bags, the percentage was between 0.2% and 0.7%. Figure 7.3 shows the powder (flour/fines) produced in both types of storage bags. The powder or fines was produced due to S. zeamais feeding on the grain. The GrainPro bags recorded zero (0) gram of powder weight. In the woven polypropylene bags, due to the extensive grain damage, the weight of powder recorded ranged from 48.0 to 73.7 g. In figure 7.4, the percent of S. zeamais mortality was determined. A 100.0% S. zeamais mortality was recorded in GrainPro bags. The number of live S. zeamais found in the woven polypropylene bags was extremely high. All the calculated percentage mortality in the polypropylene bags were below 10.0%, thus between 5.0% and 8.4%. Table 7.1 shows the number of dead and live S. zeamais in both types of bags and the percent mortality. Table 7.2 shows the means of the measured parameters recorded in the GrainPro and polypropylene bags. The mortality in GrainPro bags (100.0%) was 187 significantly high compared to that of the woven polypropylene bags (7.2%). The mass of powder produced (g), the percentage of damaged bags, the percentage of damaged grain, and percentage of grain weight loss in the GrainPro bags were all significantly low in contrast to that of the woven polypropylene bags. 7.4. Discussion 7.4.1. Percent Number of Damaged Bags Grains, animal feed, flour, and many other products are packaged in woven polypropylene bags (indBAG, 2016). GrainPro bags are liners specially designed from high-density polyethylene with a barrier layer (Baoua et al., 2013a; Grainpro.com, 2017) used to store mostly dried grains. The resilience of both storage bags to S. zeamais is not similar. This was exhibited in the results obtained in this study. All the woven polypropylene bags (100.0%) used to store the grain were susceptible to damage by S. zeamais. The damage was caused by S. zeamais in the infested grain. The S. zeamais perforated the bags and were seen moving back and forth the inside of the bags. This resulted in many larger holes been created in the bags. In comparison, the resilience of GrainPro bags was shown in this study. None of the GrainPro bags was damaged by S. zeamais. This indicates that the mouthparts of S. zeamais are not robust enough to gnaw and perforate the GrainPro bags compared to the woven polypropylene bags. In spite of this, the few GrainPro bags that were exposed accidentally to rodents were severely damaged (fig. 7.5b). Hermetic bags are comparable to many other improved storage methods. However, there are some disadvantages including high susceptibility to physical mishandling like punctures or perforations, and scratches which may be caused by insects or rodents or sharp objects (De Groote et al., 2013; Baoua et al., 2013 b; García-Lara et al., 2013). 188 7.4.2. Percentage of damaged grain Due to the late harvest of maize, grain gets infested in the field before harvesting commences (Kaaya et al., 2005; Lane and Woloshuk, 2017). Delaying harvesting can result in many pre-harvest losses including S. zeamais infestation (ICVolunteers, 2014). Maize weevils found in grain before harvest multiply rapidly due to favorable temperature and RH. S. zeamais if not killed through chemical treatment, then an appropriate storage bags should be used. The percentage of grain damaged in the woven polypropylene bags was from 91.9% to 94.4%. This shows that S. zeamais rapidly reproduced, and caused extensive kernel damage. Although storing grain in woven polypropylene bags is not expensive there is the need to apply an insecticide (De Groote et al., 2013; Maina et al., 2016). Due to the permeability of woven polypropylene bags to air, gases are exchanged between the environment and bags, and therefore S. zeamais survive, grow, and multiply. In the GrainPro bags, the percentage of damaged grain ranged from 0.2% to 0.7%. GrainPro bags can deny weevils of oxygen (Murdock et al., 2012). S. zeamais die when denied of oxygen, and hence kernel damage due to S. zeamais is reduced or prevented. The values of damaged grain in GrainPro bags although low could be attributed to the feeding activities of the S. zeamais before their demise. Secondly, S. zeamais could survive under hermetic conditions in the first few days (Bern et al., 2011; Yakubu et al., 2011; Bbosa et al., 2017; Suleiman et al., 2018), and during this period their feeding activities might have resulted in kernel damage. Kernels found in the GrainPro bags were very clean and undamaged. Similar findings were reported by Lane and Woloshuk (2017), and Williams et al. (2017). These investigators reported low numbers of infested kernels in PICS bags while in woven polypropylene bags the number was significantly huge. Hermetic bags (GrainPro bags) are not entirely the panacea for reducing PHL because rodents can 189 compromise the integrity of such bags. Rodents can cause bag damage, spillage, and grain damage which result in PHL (fig. 7.7b). Therefore, hermetic bags must be properly kept away from storage pests like rodents. 7.4.3. Mass of powder (fines) and grain weight loss In the GrainPro bags, no powder was produced which might be attributed to the early demise of all the S. zeamais. Because of the early demise of the S. zeamais, the kernels remained undamaged (whole without holes) and safe for consumption and possible germination. The mass of powder in the woven polypropylene bags was between 48.0 and 73.7 g, which could be ascribed to the extensive grain damage caused by the S. zeamais. The extensive feeding activity of S. zeamais on the grain might have resulted in the huge mass of powder produced (fig. 7.7a). The massive mass of powder exposes the ineffectiveness of the woven polypropylene bag as a suitable storage package. Most especially when the grain is already infested before storage. It was not surprising that the kernels found in the woven polypropylene bags had only the hull and bran remnants without the endosperm and embryo. The S. zeamais completely devoured the entire endosperm and germ (embryo) in all kernels. The powder produced means the grain had been rendered useless both as food and seed. Grain infestations cause quality and quantity losses limiting food accessibility to humans and animals (Rajendran, 2005; Suleiman et al., 2018). The higher the grain weight loss or mass of powder, the massive the grain uselessness. Recently, Walker et al. (2018) found that grain when hermetically stored reduces grain weight loss. Grain storage was completely ineffective and unsafe when woven polypropylene bags were used. However, the hermetic bags were effective at 190 protecting the stored grain against S. zeamais, as similarly reported earlier (Murdock et al., 2012; Baoua et al., 2014; Suleiman et al., 2018). 7.4.4. Percent S. zeamais mortality Farmers use different kinds of indigenous and pseudo effective methods to disinfest grain. Aside from the application of synthetic chemicals, farmers bask the infested grain in the sun for S. zeamais to fly out. Although many of the S. zeamais fly out, a sizable proportion remains and continue the grain damaging activity. Farmers also sieve out S. zeamais from the bulk grain. This method is extremely tedious, and ineffective because the eggs and adult S. zeamais that escape the sieving continue their life cycle and cause grain damage. Farmers also commonly soak the infested grain in water for the S. zeamais to stay afloat. The S. zeamais are then scooped out, and the retained grain is used. This method is equally ineffective as grain quality and quantity are already lost, and the grain retained still has some S. zeamais embedded in it. The effectiveness of the above methods to control S. zeamais is in contrast to the use of GrainPro bags. The 100.0% mortality in GrainPro bags shows that S. zeamais were not able to survive in the bags. The high mortality reveals that grain could be stored safely in GrainPro bags without S. zeamais attacks. Thus, the life cycle and multiplication of S. zeamais that were within the GrainPro bags were curtailed. In a situation where harvested grain becomes infested before storage, it would be most convenient and appropriate to store the grain in hermetic bags (GrainPro bags). Findings from Murdock et al. (2012), and Murdock and Baoua (2014) showed that the effectiveness of using hermetic technology depends on O2 depletion and the rise in CO2 concentrations. This is due to the respiratory ability of the insects and grain. In this study, S. zeamais in the GrainPro bags might have been denied O2. This is because O2 concentration in airtight bags depletes with time, and CO2 191 concentration increases with time (Yakubu et al., 2011; Murdock and Bauoa, 2014; Bbosa et al., 2017; Suleiman et al., 2018). In the woven polypropylene bags, many live S. zeamais were found, and the percent mortality was very low (5.0% to 8.4%). The S. zeamais had access to oxygen, hence respired, multiplied and caused serious kernel damage through their rigorous feeding activities. According to Throne (1994), the development of S. zeamais spans about 35 days. Therefore, under optimum conditions, many generations of S. zeamais might have occurred within the 6 months of storage. The favorable temperature and humidity might have enhanced the propensity of the female S. zeamais to deposit many eggs (Throne, 1994). Hence a large number of S. zeamais in the woven polypropylene bags. The low mortality recorded in the woven polypropylene bags was not surprising. The reason might be that the rate of S. zeamais multiplication far exceeded the rate of mortality. A study in a warmer environment (Arkansas) by Lane and Woloshuk (2017) asserted that the insect population was distinctively high in woven polypropylene bags compared to PICS bags. The results obtained in this current study affirm that assertion. 7.4.5. Statistical comparison of woven polypropylene and GrainPro bags The mean S. zeamais mortality was significantly higher in the GrainPro bags than woven polypropylene bags (100.0% and 7.2% respectively). The mass of powder produced (g), the percentage of damaged bags, the percentage of damaged grain, and percentage of grain weight loss were significantly low in the GrainPro bags compared to woven polypropylene bags. Based on the measured parameters, GrainPro bags proved a better method for storing grain even if the grain was previously infested. S. zeamais could not survive in the GrainPro bags, and therefore, the grain quality and quantity were maintained. The woven polypropylene bags, in this case, were similar to the three indigenous methods 192 discussed earlier. Thus, they were not efficient in controlling S. zeamais, most especially when grain was previously infested. This study supports many findings that have reported on the efficacy of hermetic bags (Murdock et al., 2012; Njoroge et al., 2014; Amadou et al., 2016; Bbosa et al., 2017; Lane and Woloshuk, 2017; Suleiman et al., 2018). Likewise, Walker et al. (2018) recently reported that a hermetically stored maize grain had reduced insect infestation and grain weight loss. The hermetic bags also have a useful lifespan of mostly two to four years (CIMMYT, 2011; Ndegwa et al., 2016), and therefore farmers reduce storage cost as bags are reused. 7.5. Conclusions A good storage results in good quality grain and high market value for the commodity. Income levels of farmers could increase to reduce poverty associated with farmers in SSA through good storage methods. Grain was safely stored in GrainPro bags compared to polypropylene bags. The 100.0% S. zeamais mortality could be the reason why grain damage was reduced in GrainPro bags. Farmers could make good earnings by storing grain in hermetic bags, most importantly if devoid of rodents. Utilization of synthetic chemicals and indigenous pseudo effective methods should be replaced with hermetic bags. Profit margins of farmers could increase when grain quality and quantity are maintained. Farmers could then become financially invigorated since hermetic bags are reusable. 193 7.6. References Adams, J. M., & Schulten, G. G. M. (1978). Loss caused by insects, mites, and micro- organisms. In: K. L. Harris & C. L. Lindbland (Eds.), Post-harvest Grain Loss Assessment Methods (pp. 83-95). USA: American Association of Cereal Chemists Addo, S., Birkinshaw, L. A., & Hodges, R. J. (2002). Ten years after the arrival in Ghana of Larger Grain Borer: farmers' responses and adoption of IPM strategies. Int J Pest Ma., 48, 315-325. Amadou, L., Baoua, I., Baributsa, D., Williams, S., & Murdock, L. (2016). Triple bag hermetic technology for controlling a bruchid (Spermophagus sp.) (Coleoptera, Chrysomelidae) in stored Hibiscus sabdariffa grain. J. Stored Prod. Res., 69, 22- 25. Baoua, I. B., Margam, V., Amadou, L., & Murdock, L. L. (2012). Performance of triple bagging hermetic technology for postharvest storage of cowpea grain in Niger. J. Stored Prod. Res., 51, 81–85. Baoua, I. B., Amadou, L., & Murdock, L. L. (2013a). Triple bagging for cowpea storage in rural Niger: Questions farmers ask. J. Stored Prod. Res., 52, 86-92. Baoua, I. B., Amadou, L., Lowenberg-Deboer, J. D., & Murdock, L. L. (2013b). Side by side comparison of GrainPro and PICS bags for postharvest preservation of cowpea grain in Niger. J. Stored Prod. Res., 54, 13–16. Baoua, I. 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J. Stored Prod. Res., 49, 166-170. Murdock, L. L., & Baoua, I. B. (2014). On Purdue improved cowpea storage (PICS) technology: Background, mode of action, future prospects. J. Stored Prod. Res., 58, 3-11. Naik, S. N., & Kaushik, G. (2017). Grain Storage in India: An Overview. http://www.vigyanprasar.gov.in/Radioserials/GrainStorageinIndiabyProf.S.N.Nai k,IITDelhi.pdf. Retrieved on 5 July 2017. Ndegwa, M. K., De Groote, H., Gitonga, Z. M., & Bruce, A. Y. (2016). Effectiveness and economics of hermetic bags for maize storage: Results of a randomized controlled trial in Kenya. Crop Prot., 90, 17–26. Njoroge, A. W., Affognon, H. D., Mutungi, C. M., Manono, J., Lamuka, P. O., & Murdock, L. L. (2014).Triple bag hermetic storage delivers a lethal punch to Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae) in stored maize. J. Stored Prod. Res., 58, 12-19. Rajendran, S. (2005). Detection of insect infestation in stored foods. Adv. Fd. Nutr. Res., 49, 163-232. Rajendran, S., & Sriranjini, V. (2008). Plant products as fumigants for stored-product insect control. J. Stored Prod. Res., 44, 126–135. Rugumamu, C. P. (2012). A technique for assessment of intrinsic resistance of maize varieties for the control of Sitophilus zeamais (Coleoptera: Curculionidae). TaJONAS Tanzan. J. Nat. Appl. Sci., 3, 481–488. SDC. (2017). Swiss Agency for Development and Cooperation. Central America: Fighting Poverty with Silos and Job Creation. Available online: Security/focusareas/Documents/phm_sdc_latin_brief_silos_central_america_e.pdf . Retrieved on 10 January 2017. 196 Suleiman, R., Bern, C. J., Brumm, T. J., & Rosentrater, K. A. (2018). Impact of moisture content and maize weevils on maize quality during hermetic and non-hermetic storage. J. Stored Prod. Res., 78, 1-10. Tefera, T., Kanampiu, F., De Groote, H., Hellin, J., Mugo, S., Kimenju, S.… Banziger, M. (2011). The metal silo: An effective grain storage technology for reducing post- harvest insect and pathogen losses in maize while improving smallholder farmers’ food security in developing countries. Crop Prot., 30, 240–245. Throne, J. E. (1994). Life-history of immature maize weevils (Coleoptera, Curculionidae) on corn stored at constant temperatures and relative humidities in the laboratory. Environ. Entomol., 23, 1459-1471. USDA. (2013). Grain Inspection Handbook Book II: Grain Grading Procedures. Chapter 4-Corn, page 10. Revised on April 11, 2017. Retrieved on 6 February 2018. Walker, S., Jaime, R., Kagot, V., & Probst, C. (2018). Comparative effects of hermetic and traditional storage devices on maize grain: Mycotoxin development, insect infestation, and grain quality. J. Stored Prod. Res., 77, 34-44. Williams, S. B., Murdock, L. L., & Baributsa, D. (2017). Storage of maize in Purdue improved crop storage (PICS) bags. PLoS ONE, 12(1), e0168624. World Bank. (2011). Missing food: the case of postharvest grain losses in Sub-Saharan Africa. Washington, DC. 2011. World Bank. https://openknowledge.worldbank.org/handle/10986/2824. Retrieved on 6 February 2018. Yakubu, A., Bern, C. J., Coats, J. R., & Bailey, T. B. (2011). Hermetic on-farm storage for maize weevil control in East Africa. African Journal of Agricultural Research, 6, 3311-3319. 197 Figures 120.0 100.0 zeamais . . S 80.0 60.0 40.0 20.0 Percent of storage bags damaged by damaged bags storage of Percent 0.0 F1 F2 F3 F4 F5 F6 F7 F8 Farmers Woven Polypropylene bag GrainPro bag Figure 7.1. Percent of Woven Polypropylene and GrainPro Bags Damaged by S. zeamais during the 6 Months of Grain Storage in Ghana. 198 100.0 94.4 94.0 92.1 92.6 91.9 93.5 92.4 90.0 80.0 S. zeamais S. 70.0 60.0 50.0 40.0 30.0 20.0 10.0 Percent weight of grain damaged by by grain of damaged weight Percent 0.5 0.3 0.7 0.2 0.5 0.7 0.3 0.0 F1 F2 F3 F4 F5 F6 F7 F8 Farmers Woven Polypropylene bag GrainPro bag Figure 7.2. Percent of Maize Grain Damaged by S. zeamais in Both Bags during the 6 Months of Grain Storage in Ghana. 199 80.0 73.7 70.9 70.0 67.5 63.1 60.0 53.2 54.2 50.0 48.0 40.0 30.0 20.0 Weight of of produced power (g/1 kg) Weight 10.0 0 0 0 0 0 0 0 0.0 F1 F2 F3 F4 F5 F6 F7 F8 Farmers Woven Polypropylene GrainPro Figure 7.3. Weight (g/1 kg) of Powder Produced as a Result of Grain Damaged by S. zeamais during the 6 Months of Grain Storage in Ghana. 200 120.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 80.0 S. zeamais S. 60.0 40.0 Percent mortality of mortality Percent 20.0 6.5 6.3 7.6 5.0 8.5 5.6 8.4 0.0 F1 F2 F3 F4 F5 F6 F7 F8 Farmers Woven Polypropylene bag GrainPro bag Figure 7.4. Percent Mortality of S. zeamais in Both Storage Bags during the 6 Months of Grain Storage in Ghana. 201 a b c Figure 7.5. Maize Grain in Intact (a) and Mice-Damaged (b) GrainPro Bags; and Maize Grain in Damaged Woven Polypropylene Bags (c) During the 6 Months of Grain Storage in Ghana. a b Figure 7.6. The Quality of Maize Kernels Stored in Woven Polypropylene Bags (a) and GrainPro Bags (b) During the 6 Months of Grain Storage in Ghana. 202 a b Figure 7.7. Powder (flour) Produced in Woven Polypropylene Bags Due to S. zeamais (a), and Kernel Spillage Due to Mice Attack on GrainPro Bags (b) During the 6 Months of Grain Storage in Ghana. 203 Tables Table 7.1. The Average Number of Live and Dead S. zeamais per 1 kg of Grain, and Percent Mortality During the 6 Months of Grain Storage in Ghana. Farmers S. zeamais in woven polypropylene S. zeamais in GrainPro bags bags Dead Alive % Mortality Dead Alive % Mortality 1 13.3 192.7 6.5 66.7 0.0 100.0 2 14.0 208.3 6.3 67.7 0.0 100.0 3 14.3 174.3 7.6 74.0 0.0 100.0 4 ------ 5 15.0 287.0 5.0 64.7 0.0 100.0 6 16.7 180.0 8.5 68.0 0.0 100.0 7 15.7 264.0 5.6 69.0 0.0 100.0 8 19.3 212.0 8.4 72.0 0.0 100.0 204 205 CHAPTER 8. EFFECTIVE CONTROL OF MOISTURE CONTENT OF STORED SEEDS IN HERMETIC STORAGE USING ZEOLITE BEADS Modified from a manuscript to be submitted to the Applied Engineering in Agriculture Abstract Sun drying of seed is unpredictable and less effective especially during the rainy seasons which often coincides with the harvesting period. Seed survival in storage depends mostly on seed moisture content (MC), hence controlling seed MC in storage is essential. Zeolite beads have microcrystalline pore structures that bind water tightly, and help reduce seed MC. The aim was to evaluate the feasibility of using zeolite beads in storing maize seeds in Ghana, and determine any effects the zeolites beads might have on seed germination and vigor. Maize seeds of the same variety at 15.3%, 11.3%, and 9.8% MC were used. Enough zeolite beads of 15.3% water absorption capacity were added to each replicate glass jar of 300.0 g seeds to achieve 9.0% MC after 1, 3 and 6 months of hermetic storage. The final MC was determined after storage, and seeds were germinated in a sand medium. Seed vigor was determined using the seedling growth rate (SGR) test. The data were either plotted or analyzed using ANOVA. So, seeds at 15.3% MC stored without zeolite beads increased moisture, and had decreased germination and vigor. The MC of seeds stored at 15.3% without zeolite beads increased MC to 15.8% and 16.4% at 3 and 6 months. The 7-days germination of seeds at 15.3% initial MC stored without zeolite beads decreased linearly from 82.0% to 53.0%, unlike the seeds at 11.3% and 9.8% initial MC stored either with zeolite beads or without zeolite beads. The SGR of seeds at 15.3% initial MC stored without zeolite beads significantly decreased at 3 and 6 months. But the SGR of the other seeds at 6 months was generally high. However, all samples with zeolite beads lost MC to similar levels, and maintained germination and vigor. Maize seeds with high 206 initial MC can be stored safely, and lose moisture during storage when using zeolite beads without a negative effect on seed germination and vigor. Keyword: Zeolite beads; maize seed; seedling growth rate; germination; moisture content. 8.1. Introduction Maize is an important crop worldwide and its grain is used as feed, food, and for industrial purposes. Farmers, particularly in Africa, are estimated to save and trade about 80.0% to 100.0% seeds of both local and improved varieties planted. These farmers, unfortunately, lack access to proper controlled-temperature or refrigerated seed storage facilities. Under poor farm-storage conditions, seed deterioration accelerates and hence seed quality is reduced (Walsh et al., 2014). Grain production is a highly profitable venture, and grain yields are dependent on early and uniform seedling emergence. To achieve uniform emergence, high productivity, and grain yields, the use of high-quality seeds is essential (Oliveira et al., 2011). Goggi et al. (2008) reiterated that seed quality is so essential in the early development and growth of crops. The use of high-quality seeds with high germination (viability) and vigor results in faster, and more uniform seedling emergence, and adequate plant stand (Del Giudice et al., 1998). Seed germination is the ability of a seed to grow and produce a seedling under favorable environments, while seed vigor is the physiological potential of seeds to grow under unfavorable environments (Marcos-Filho, 2015). The physiological potential of a seed is maximum when seed development is close to seed maturity after which seeds deteriorate. The rate at which seeds deteriorate depends on environmental conditions in the field and storage. Seed deterioration is obvious in decreased germination rate, percent germination, and increased in the number of abnormal seedlings (Marcos-Filho, 2015). 207 Seed vigor is defined as “the sum total of those properties of the seed that determine the level of activity and performance of the seed during germination and seedling emergence” (ISTA, 2006). In measuring the seedling growth rate (SGR), it is important to know stand establishment which is affected by consistency and the rate at which seedlings emerge. A vigorous seed is efficient in mobilizing stored reserves to the embryonic “root” and “shoot”, and this is observable in the growth of the seedling (Isely, 1957). Establishing the length or dry weight of seedlings is a significant vigor parameter (Pereira and Andrews, 1976). In most developing nations seeds to be used for sowing are mostly traditionally stored. Most of these storage methods are not able to store seeds safely resulting in seed deterioration (Thamaga-Chitja et al., 2004). Some factors that cause seed deterioration are land cultivated, kind of storage facility, temperature, RH, moisture, CO2, O2, features of grain, microbes, insects, rodents, and birds (Jayas and White, 2003). Most traditional drying methods dependent on radiant energy (sun drying). Sun drying is unpredictable and less intense especially during the rainy seasons which often coincides with the harvesting period. Seeds that are not effectively dried are susceptible to deterioration by any of the agents mentioned above. Despite the presence of favorable conditions for germination, deteriorated seeds tend not to germinate. Seeds stored in a natural ambient room condition constantly interact with changing temperature, relative humidity, and available oxygen. There is a high possibility of lowering metabolic activity when seeds are stored in a controlled environment such as low humidity, temperature, and oxygen. This further reduces seed aging process, and seed longevity is increased (Bewley et al., 2013). The life of a seed mostly depends on its MC, 208 hence controlling seed MC in storage is essential and it influences seed viability. Hence, to reduce MC, desiccants like silica gel, lithium chloride, calcium chloride, molecular sieve, charcoal among many others are suitable to use (Probert, 2003). Desiccants work by taking up moisture from seeds of high MC until both become equilibrated. The rate and quantity of water absorbed by a desiccant from seeds are dependent on the desiccant-seeds ratio, storage temperature, and water absorption capacity of desiccant. The use of zeolite beads (Aluminum silicate ceramics/ceramic beads) has been around for years now (UC Davis, 2009). The zeolite beads have microcrystalline pore structures that bind water tightly (Hay et al., 2012; Hay and Timple, 2013). Activated zeolite beads could take up water to about 20-25% of its dry weight (Bradford et al., 2018). Zeolite beads have many advantages over other desiccants, and the advantages include high water affinity, more rapid drying, no hysteresis effect, and easy to be activated at 200°C for 3-4 hours. Many findings have indicated that seeds stored with zeolite beads were dried without any effects on germination of seeds. Hay et al. (2012) found that zeolite beads could dry high moisture seeds of rice to targeted MC of 6.1% and 4.2%, and germination was also high after 371 days of storage. Similarly, Khanal and Paudel (2014) indicated that drying freshly harvested vegetable seeds to low moisture was effective when zeolite beads were used, and the germination percentage was high compared to seeds without beads. However, the proportion of seeds-to-zeolite beads ratio is so important to avoid under drying or extreme desiccation that can cause seeds to deteriorate (Hay et al., 2012; Hay and Timple, 2013). It is important to invest in good seed storage techniques, particularly in Africa where farmers are dependent on self-harvested seeds. First, a good seed storage technique is most appropriate in situations of unpredictable natural stresses like droughts or floods. 209 Second, since most of these traditional seed storage methods are undependable, there is a need to have a dependable technique to dry and/or store seeds safely. Due to these challenges, the aim of this study was to evaluate the efficacy of zeolite beads in farmers’ storage of maize seeds in Ghana, and to assess any effects the zeolites beads might have on seed germination (viability) and vigor. 8.2. Materials and Methods 8.2.1. Reactivation of zeolite beads, and determination of zeolite beads capacity The zeolite beads were reactivated for 2.5 hours by baking in an air-convection oven at 200°C. The activated beads were then taken out of the oven, and placed in dry borosilicate glass desiccators. The glass desiccators were vacuum sealed using Dow Corning high vacuum grease, and then covered. The moisture-proof glass desiccators containing zeolite beads were kept for further studies in the laboratory of the Radiation Technology Centre, Ghana Atomic Energy Commission. Triplicate samples (100.0 g) of the cooled reactivated zeolite beads were taken to determine the zeolite beads water-holding capacity. The samples were soaked in an excess volume of water. After 3 minutes, the zeolite beads were removed and excess water was wiped with paper towel, and then reweighed (W1). The wet zeolite beads were incubated in a glass desiccator over excess quantity of reactivated beads and reweighed after 24 hours (W2). The final zeolite beads water-holding capacity was corrected by adding 20% more to the calculated beads capacity. The zeolite beads water-holding capacity was determined based on the protocol of UC Davis (2009). Zeolite beads water-holding capacity (%) 퐼푛𝑖푡𝑖푎푙 푧푒표푙𝑖푡푒 푏푒푎푑푠 푤푒𝑖𝑔ℎ푡 (W1)−퐹𝑖푛푎푙 푧푒표푙𝑖푡푒 푏푒푎푑푠 푤푒𝑖𝑔ℎ푡(W2) = *100……………….. (8.1). 퐼푛𝑖푡𝑖푎푙 푧푒표푙𝑖푡푒 푏푒푎푑푠 푤푒𝑖𝑔ℎ푡 (W1) The zeolite beads water-holding capacity used in this study was 15.3%. 210 8.2.2. Determination of seeds moisture content (MC) The same seed variety was obtained from the farm gate. The seeds were further sun-dried to MC of 15.3%, 11.3%, and 9.8%. These represented the initial MC of seeds used in the study. The MC of the seed lot before storage and after storage were determined. Triplicate samples of 5.0 g of ground seeds were put in Petri dishes and then placed in an air convection oven for 2 hours at 130°C (ISTA, 2005). After cooling, the percent MC (wet based) was then calculated. 8.2.3. Estimating the appropriate quantity of zeolite beads necessary for safe seed storage About 300.0 g of each of the 15.3%, 11.3%, and 9.8% MC seeds were weighed into 900 ml glass jars. The number of zeolite beads was calculated using the zeolite beads manufacturer’s spreadsheet provided for calculation based on the initial and expected MC of seeds, and zeolite beads capacity (UC Davis, 2009). The expected MC of seeds after storage was 9.0%. About 137.0 g, 50.1 g, and 17.3 g of zeolite beads were added respectively to the seeds of MC 15.3%, 11.3%, and 9.8%. The glass jars were hermetically sealed using Dow Corning high vacuum grease and then covered. The jars were also covered with paraffin film to ensure hermetic condition existed. The jars were then stored in two different room conditions for 1, 3, and 6 months. The room temperature conditions were 18±1oC and 27±4oC. 8.2.4. Experimental design There were 2 treatments (seeds with zeolite beads) and 1 control (seeds without zeolite beads) per storage length, 2 temperature storage conditions, 3 initial seed MC, and 3 different months of storage were used in a completely randomized design (3*3*3*2). 211 8.2.5. Determination of seed germinability, viability, and vigor after storage Seeds that had MC below 8.0% were allowed to equilibrate for 7 days at ambient conditions before planting (According to users’ protocol for the beads). Sand was obtained from a river bank in Ghana. Trays were filled with the sand, and seeds were sown at about 2 cm depth. Four replicates of 50 seeds (200 seeds) were randomly sampled from each seed lot in the germination test. The watered trays were kept at room temperature (25±2oC) for germination. Germination was done for 7 days, and counting of germinated seeds was done on the 4 and 7 days (AOSA, 1988). At the end of 7 days, the total number of dead seeds, and abnormal and normal seedlings were recorded. To determine the seed vigor, seedling growth rate (SGR) test was evaluated (AOSA, 1988). The abnormal seedlings were discarded, and sand was washed off the root of normal seedlings and blotted. The shoots and roots of the normal seedlings were cut free from the kernels at the juncture/point of the mesocotyl. The cut mesocotyl and kernels were discarded while the shoot and root materials (seedlings) were placed in coin envelopes for drying. Seedlings were dried at 80oC for 24 hours in an oven, then weighed to the nearest mg to obtain seedling dry weight. SGR (mg/seedling) was calculated by the equation: Seedling dry weight (mg) SGR = ………………………………………………. (8.2). Number of normal seedlings 8.2.6. Data analysis Data on MC, and seedling growth rate (SGR) were analyzed using ANOVA, and mean differences were separated using Tukey-Kramer HSD (p < 0.05). Germination percentage (PG) data at 4 and 7 days of germination also were plotted. 212 8.3. Results and Discussion 8.3.1. The effectiveness of the zeolite beads in seed drying In table 8.1, seed moisture contents (MC) were drastically reduced from the initial 9.8%, 11.3%, and 15.3% to a range between 8.3% and 8.7%, 8.6% and 9.1%, and 6.2% and 6.8%, respectively, when seeds were stored with zeolite beads in hermetic glass jars. The MC of seeds with initial MC of 9.8% and 11.3% stored without zeolite beads remained relatively close to their initial MC after 1, 3 and 6 months of storage. The MC of seeds with an initial MC of 15.3% stored without zeolite beads increased MC at 3 and 6 months of storage to 15.8% and 16.4% respectively. The warm or cold storage temperature did not significantly influence the MC of seeds in both, the control and zeolite beads storage containers. The possibility of drying seeds to low MC as in this study is rare in rainy seasons. Hence, storing seeds with zeolite beads eliminates challenges associated with sun drying and other desiccants. The zeolite beads remove moisture from wet seed until both reach an equilibrium. These results demonstrated that activated zeolite beads can reduce seed MC to a safe level. The findings from this study are comparable to others (UC Davis, 2009; Hay et al., 2012; Hay and Timple, 2013; Bradford et al., 2014). These investigators also indicated that zeolite beads can effectively dry seeds to acceptably low moisture. Hay et al. (2012) dried freshly harvested rice seeds to targeted moisture contents of 6.1% and 4.2% using zeolite beads. Khanal and Paudel (2014) dried freshly harvested vegetable seeds to low MC of less than 9.0% using zeolite beads. Prasad (2013) was able to dry Greengram seeds with zeolite beads from 9.98% to 6.10% and 6.06% in 68 hours and 9 months of storage, respectively. Similar results were obtained when zeolite beads were used by Keshavulu et al. (2012) to dry soybean seeds from 12.0% to approximately 4.5% in 21 213 months, and cucumber seeds from 14.0% to 5.0% in less than 1 hour (Asbrouck and Tarido, 2009). This novel method of drying seed is an excellent opportunity for farmers in Ghana and other SSA where seed drying is mostly dependent on sun drying, which is problematic especially during rainy seasons. During the rainy season, the supply of radiant energy is intermittent and less intense which hinders efficient and fast seed drying. In such situations, seeds become moldy and subsequently deteriorate in storage. 8.3.2. Precision and accuracy of zeolite beads in estimating the final MC of seeds In table 8.2, the MC of seeds with an initial MC of 9.8% stored with zeolite beads for 1 and 3 months in both the warm and cold rooms had final MC significantly lower than the expected MC. However, when the storage was extended to 6 months, there was no significant difference between the final and expected MC. Seeds with initial MC of 11.3% stored with zeolite beads had a final MC not significantly different from the expected MC at 1, 3, and 6 months, irrespective of the storage room temperature. Seeds with initial MC of 15.3% stored with zeolite beads had significantly lower final MC than the expected MC in both, warm and cold rooms after 1, 3, and 6 months of storage. In reference to seeds from all other initial MC values stored without zeolite beads (controls), the final MC was significantly high, compared to the expected and final MC of seeds stored with zeolite beads. The warm or cold storage temperatures did not statistically significantly affect the final MC of seeds. According to the results, except for seeds with initial MC of 11.3%, the estimated final MC was not statistically precise and accurate in most cases. Despite this, however, it is worth noting the statistically significant low final MC of seeds compared to the initial MC of seeds. The zeolite beads efficacy as a drying agent can be considered as precise but not accurate at a specific seed moisture level. For example, the zeolite beads efficacy was 214 precise and accurate for estimating the final MC for seeds with initial MC of 11.3%. The 6.8%, 6.2%, and 6.4% final MC were obtained for seeds with an initial MC of 15.3% respectively at 1, 3, and 6 months of storage. Accuracy in this study refers to how close the final MC measurements were to the expected MC, while precision refers to how consistently the final MC measurements were repeated at a specific moisture level. In a study by Hay et al. (2012), a large discrepancy between the expected MC (6.1%) and actual MC (> 10.0%) was reported after days of drying rice seeds with zeolite beads. Contrary to this study, the final MC was higher than the expected MC, and the discrepancy was not wide. In the same study by Hay et al. (2012) a low final MC (4.2%) of seeds was recorded when the number of zeolite beads was tripled. Very low final MC of 4.0% or below can be damaging to seeds due to extreme desiccation. Extreme desiccation makes seeds lose longevity potential (Ellis et al., 1995). The proportion of seeds-to-zeolite beads ratio is critical to avoid excessive drying or extreme desiccation which causes a seed to deteriorate (Hay et al., 2012; Hay and Timple, 2013). Khanal and Paudel (2014) reported that drying freshly harvested vegetable seeds with zeolite beads was effective, however, this depended upon the size (large, medium and small) of the seeds if the same quantity of zeolite beads were used. The warm or cold storage conditions did not significantly impact the final MC of seeds, and therefore, farmers do not have to refrigerate seeds stored with zeolite beads. 8.3.3. Effects of zeolite beads on seed germination at 4 and 7 days Figure 8.1 shows the PG at 4 days. Seeds with initial MC of 15.3% stored without zeolite beads had low PG at 1 month of storage. The PG further decreased at 3 months, and the lowest PG was recorded at 6 months. However, seeds with initial MC of 15.3% stored with zeolite beads, had the highest PG when compared to seeds from all the other initial MC values and stored with or without zeolite beads. Seeds from all the other initial MC 215 values stored with or without zeolite beads increased in PG, but the PG was not linearly related to the increasing storage months. Germination at 4 days was generally not influenced by storage temperature. A clear pattern of germination was not seen at 4 days. Since temperature and soil MC were favorable, the non-uniform germination at 4 days may be due to sand medium effect. The seeds might have germinated and shoots buried within the sand at 4 days, delaying shoots emergence through the sand crust and hence, low PG. A clear pattern of PG of seeds at 7 days is shown in figure 8.2. PG of seeds with initial MC of 15.3% and stored without zeolite beads decreased linearly from 82.0% to 53.0% in the 6 months of storage. The PG of seeds with initial MC of 11.3% and 9.8% and stored with or without zeolite beads, and seeds with initial MC of 15.3% stored with zeolite beads increased almost linearly 91.0% to 99.0% from the first to 6th months of storage. The most important observation was the high PG of nearly 100.0% at 6 months of storage (> 95.0%). The decline in PG experienced by seeds stored at high initial MC (15.3%) without zeolite beads may be attributed to seed deterioration. These seeds experienced an increase in MC, which likely resulted in increased rate of seed respiration and metabolism (Bewley et al., 2013). This further resulted in the formation of water vapor and heat in the stored seeds. The high seed MC and heat are conducive to initiate quick seed deterioration within a short time. Seeds are hygroscopic and therefore take up and release moisture to reach equilibrium. The absence of zeolite beads that might have absorbed the excess moisture could be the reason for the deterioration. Lipid peroxidation is the likely cause as it is initiated in seeds of MC above 14.0% (Malik and Jyoti, 2013). The increased water content might have activated hydrolytic oxidative enzymes such as lipoxygenase. In the presence of oxygen and water, lipoxygenase is activated against unsaturated fatty acids, and lipid 216 peroxidation is initiated, propagated and completed. Lipid peroxidation is progressive and retards only when there is a metabolic intervention. When seed deterioration happens, the process cannot be reversed. This was evident as PG was reduced, and was worsened at 6 months of storage. Besides the seeds with initial MC of 15.3% stored without zeolite beads, all the seeds with initial MC stored with or without zeolite beads had high PG at 7 days. These seeds had between 6.0% and 12.0% MC. Lipid peroxidation is less likely in seeds with MC ranging from 6.0% to 14.0%. The limited moisture available cannot initiate autoxidative lipid peroxidation, and at the same time, the moisture is insufficient to activate lipoxygenase enzymes to initiate lipid peroxidation (Malik and Jyoti, 2013). Seeds with initial MC of 9.8% and 11.3% stored without zeolite beads were safely stored similar to seeds stored with zeolite beads because their initial MC was within the safe MC limit for storage. Importantly, seeds with initial MC of 9.8%, 11.3% and 15.3% stored with zeolite beads experienced decreased MC, and also had safe storage. First, the final MC was not below 6.0% to initiate any autoxidative lipid peroxidation. Mostly the primary cause of lipid autoxidation is seed MC below 6.0% (Malik and Jyoti, 2013). Second, any excess moisture produced from seed respiration and metabolism might have been absorbed by the zeolite beads. Therefore, seeds were stored safely, and thus, seed deterioration was controlled which reflects in high PG up to the 6th month of storage. Limited oxygen coupled with low seed MC in the airtight jars might have also prevented seeds from autoxidative lipid peroxidation (Chang et al., 2004; Miah et al., 2006). The expected PG of a good-quality maize seed should be above 90.0% (Walsh et al., 2014). In this study, PG of maize seed was more than 95.0% even at 6 months of storage 217 using zeolite beads. The zeolite beads maintained seed PG (7 days) or seed viability over the entire storage period of 6 months, even seeds at a low initial MC of 9.8%. Increased in PG of maize seeds was observed from 1 to 3 months in storage (DeVries et al., 2007). The high PG or seed viability presently record is comparable to findings by Hay et al. (2012) when they used zeolite beads to store rice seeds. Others studies have reported on the effectiveness of zeolite beads to dry different kinds of seeds. Prasad (2013) indicated that after storing green gram seeds with zeolite beads for 9 months maintained high germination of 92.0%. Even though the storage period in this study was less than 9 months, the PG of seeds stored with zeolite beads was above 95.0%. In a study conducted by Keshavulu et al. (2012), they concluded that soybean seeds stored with zeolite beads maintained their viability after 21 months of storage. The PG of maize seeds stored with zeolite beads is estimated to be maintained or increased when storage is done for many months. It is important that this study reiterated the effectiveness of maintaining seed viability when zeolite beads are used in seed storage. It is worth mentioning that, even at high temperatures (>25.0oC), drying of seeds with zeolite beads was not detrimental to seeds viability, hence, PG of seeds was high. Hay et al. (2012) in drying rice seeds made a similar observation. This is very important since the average yearly temperature in tropical areas is above 25.0%. Most smallholder farmers are found in tropical areas like Ghana and other SSA or developing countries. Consequently, farmers can fully benefit from using zeolite beads to store seeds irrespective of storage temperature. 8.3.4. Effect of zeolite beads on SGR In table 8.3, SGR of seeds stored with or without zeolite beads at 1, 3, and 6 months of storage was compared. SGR of seeds with initial MC of 9.8% and 11.3% stored with or without zeolite beads within 1 or 3 or 6 months of seed storage were not significantly 218 different. The only exception was the SGR of seeds with initial MC of 9.8% stored without zeolite beads in a warm room which had low SGR of 36.5 mg/seedling. The storage temperatures did not have a significant effect on SGR. SGR of seeds with initial MC of 15.3% stored without zeolite beads was significantly low at 3 (33.7 and 35.9 mg/seedling) and 6 months (25.4 and 25.0 mg/seedling). SGR of seeds with initial MC of 9.8%, 11.3% and 15.3% stored with zeolite beads were high even at 6 months of storage. Generally, at 6 months SGR was high. Vigor tests are used to estimate how a seed lot would perform in the field (Copeland and McDonald, 2001). Seedlings grown from seed lots with higher seed vigor are stronger, hence seedling establishment under a wide range of field conditions is enhanced. This creates a better green cover in the field, and more vigorous plants are finally produced (Sulewska et al., 2014). SGR measures the metabolic potential of the seed when transferring stored reserves from the seed into the growing seedling. As seeds deteriorate and metabolic processes slow down, SGR is reduced. The low SGR of seeds with high initial MC stored without zeolite beads might be due to rapid seed deterioration. The seed deterioration could be due to the death of tissues in the seeds (Marcos-Filho, 2015), as the MC of seeds increased in storage. The increased seed MC might have propagated seed aging which affects seed vigor. According to Isely (1957), vigorous seeds are efficient in mobilizing food reserves from storage to the “root” and “shoot” of the developing embryo, which is reflected in the growth of seedling. Therefore, a low SGR reported for seeds with initial MC of 15.3% stored without zeolite beads might indicate low plant stand establishment and poor field performance. On the contrary, seeds stored with or without zeolite beads with high SGR might be due to reduced or no seed deterioration. The zeolite 219 beads might have reduced seed MC to lower levels that minimized the rate of seed deterioration. Hence, seed vigor was high which resulted in high SGR even when seeds were stored for 6 months. Good stand establishment and field performance are expected of these seeds. A study by TeKrony et al. (1989a) reported a positive correlation between vigor index and seed emergence. Thus, a less vigor seed lot has minimal emergence and reduced SGR compared to seed lots with high vigor (TeKrony et al., 1989b). The findings of (Kaydan and Yagmur, 2008; Javad and Mohammad, 2011; Prasad, 2013; Sulewska et al., 2014) reiterated the importance of high SGR maize seeds to achieve good stand establishment and field performance. 8.4. Conclusions This study therefore reiterates that using zeolite beads is a safe, fast, user-friendly, inexpensive, and adaptable method for drying maize and other cereal seeds without compromising the seed quality during storage. Seeds stored with zeolite beads did not require the use of refrigeration to maintain seed viability and vigor. This study also indicates that the formula used in calculating zeolite beads-to-seed ratio should be revised to prevent extreme desiccation which could be detrimental to seed quality. Farmers in Ghana and SSA are therefore recommended to use zeolite beads to dry or store seeds of even high MC as radiant energy is undependable and unpredictable. Importantly, after storage, the zeolite beads can be retrieved, reactivated and reused for many years. 220 8.5. References Asbrouck, J. V., & Taridno, P. (2009). Fast field drying as a method to maintain quality, increase shelf life and prevent post-harvest infections on Cucumis sativum L. Asian Journal of Food and Agro-Industry, Special Issue, S133-S137. AOSA. (1988). Association of Official Seed Analysts. 1988. Rules for Testing Seeds. J. Seed Tech., 12(3). Bewley, J. D., Bradford, K. J., Hilhorst, H. W. M., & Nonogaki, H. (2013). Seeds: Physiology of development, germination, and dormancy (3rd Ed). Publisher’ Graphics LLC. Springer New York-Heidelberg Dordrecht London. pp. 346-364. Bradford, K. J., Dahal, P., Day, R., Phiri, N.A, Musebe, R., Karanja, D.…Van Asbrouk, J. (2014). Improving seed quality for smallholders. www.dryingbeads.org. Retrieved on 21 August 2018. Bradford, K. J., Dahal, P., Asbrouk, J. V., Kunusoth, K., Bello, P., Thompson, J., & Wu, F. (2018). The dry chain: Reducing postharvest losses and improving food safety in humid climates. Trends in Food Science and Technology, 71, 84–93. Chang, S. K. C., Liu, Z. S., Hou, H. J., & Wilson, L. A. (2004). Influence of storage on the characteristics of soybean, soymilk and tofu. Proc. VII- World Soybean Res. Con., IV-In: Soybean Proc. and Util. Con., III- Congresso Brasileiro de Soja Brazilian Soybean Congress, Foz do Iguassu, PR, Brazil, 29 February-5 March, 977-983. Copeland, L. O., & McDonald, M. B. (Eds.) (2001). Principles of Seed Science and Technology, 4th ed. Kluwer Academic Publishers, Massachusetts, pp. 124–128. Del Giúdice, M. P., Reis, M. S., Sediyama, T., & Mosquim, P. R. (1998). Avaliação da qualidade fisiológica de sementes de soja submetidas ao condicionamento osmótico em diferentes temperaturas. Revista Brasileira de Sementes, 20(2), 245-262. DeVries, M., Goggi, A. S., & Moore, K. (2007). Determining seed performance of frost damaged seed lots. Crop Science 47, 2089-2097. Ellis, R. H., Hong, T. D., & Roberts, E. H. (1995). Survival and vigor of lettuce (Lactuca sativa L.) and sunflower (Helianthus annuus L.) seeds stored at low and very-low moisture contents. Annals of Botany, 76, 521-534. Goggi, A. S., Caragea, P., Pollak, L., McAndrews, G., DeVries, M., & Montgomery, K. (2008). Seed quality assurance in maize breeding programs: Tests to explain variations in maize inbreds and populations. Agronomy Journal, 100(2), 337-343. Hay, F. R., Thavong, P., Taridno, P., & Timple, S. (2012). Evaluation of zeolite seed ‘Drying Beads®’ for drying rice seeds to low moisture content prior to long-term storage. Seed Sci. & Technol., 40, 374-395. 221 Hay, F. R., & Timple, S. (2013). Optimum ratios of zeolite seed Drying Beads® to dry rice seeds for genebank storage. Seed Sci. & Technol., 41(3), 407-419. ISTA. (2005). International Rules for Seed Testing. International Seed Testing Association, Bassersdorf, Switzerland. ISTA. (2006). International Seed Testing Association. International rules for seed testing. Seed Science and Technology. Basserdorf, Switzerland. Isely, D. (1957). Vigor tests. Proceedings of Association of Official Seed Analysts, 47, 176- 182. Javad A., & Mohammad R. A. (2011). The effects of seed size on germination and early seedling growth of pelleted seeds of sugar beet. Journal of Applied Sciences Research, 7(8), 1257–1260. Jayas, D. S., & White, N. D. G. (2003). Storage and drying of grain in Canada: Low cost approaches. Food Control, 14, 255–261. Kaydan, D., & Yagmur, M. (2008). Germination, seedling growth and relative water content of shoot in different seed sizes of triticale under osmotic stress of water and NaCl. African Journal of Biotechnology, 7(16), 2862–2868. Keshavulu, K., Dhal, P., Van Asbrouck, J. V., & Bradford, K. J. (2012). New technology for post-harvest drying and storage of seeds. Seed Times, 5, 33-38. Khanal, A., & Pratima, P. (2014). Evaluation of zeolite beads technology for drying vegetable seeds to low moisture content prior to long-term storage in Nepal. International Journal of Research, 1(8), 140-149. Malik, C. P., & Jyoti, M. (2013). Seed deterioration: A review. Int. J. LifeSc. Bt & Pharm. Res., 2(3), 375-385. Marcos-Filho, J. (2015). Seed vigor testing: an overview of the past, present, and future perspective. Sci. Agric. (Piracicaba, Braz.), 72(4). http://www.scielo.br/scielo.php?pid=S0103162015000400363&script=sci_arttext &tlng=es. Retrieved on 11 August 2018. Miah, M. A. B., Rahman, M. M., & Haque, M. M. (2006). Effect of relative humidity on germination and vigour of soybean seed. Inter. J. Eng. Technol. 3(1): 17-24. Oliveira, A. C. S., Coelho, F. C., Vieira, H. D., & Rubim, R. F. (2011). Armazenamento de sementes de milho emembalagens reutilizáveis, sob dois ambientes. Revista Brasileira de Milho e Sorgo, 10(1), 7-28. 222 Pereira, L. A. G., & Andrews, C. H. (1976). Comparison of vigor tests for the evaluation of soybean seed physiological quality. Semente, 2, 15-25. Prasad, A. L. (2013). Effect of desiccants on seed storability and pulse beetle infestation in greengram (Vigna radiata L. Wilczek). M.Sc. thesis. Rajendranagar, Hyderabad: Acharya N.G. Ranga Agricultural University, Department of Seed Science and Technology, College of Agriculture. krishikosh.egranth.ac.in/bitstream/1/67325/1/D9316.pdf. Probert, R. J. (2003). Seed viability under ambient conditions, and the importance of drying. In: R. D. Smith, J. B. Dickie, S. H. Linington, H. W. Pritchard & R. J. Probert (Eds.), Seed conservation: Turning science into practice (pp. 337-365). Richmond, UK: Royal Botanic Gardens Kew. Sulewska, H., Śmiatacz, K., Szymańska, G., Panasiewicz, K., Bandurska, H., & Głowicka- Wołoszyn, R. (2014). Seed size effect on yield quantity and quality of maize (Zea mays L.) cultivated in South East Baltic region. Zemdirbyste-Agriculture, 101(1), 35–40. TeKrony, D. M., Egli, D. B., & Wickham, D. A. (1989a). Corn seed vigor on no-tillage field performance. I. Field emergence. Crop Sci., 29, 1523–1528. TeKrony, D. M., Egli, D. B., & Wickham, D. A. (1989b). Corn seed vigor on no-tillage field performance. II. Plant growth and grain yield. Crop Sci., 29, 1528–1531. Thamaga-Chitja, J. M., Hendriks, S. L., Ortmann, G. F., & Green, M. (2004). Impact of maize storage on rural household food security in northern KwaZulu-Natal. Journal of Family Ecology and Consumer Science, 32, 8–15. UC Davis. (2009). New technology for postharvest drying and storage of horticultural seeds. www.hortcrsp.ucdavis.edu/main/4seeds.html. (Retrieved on 1 September 2018). Walsh, S., Potts, M., Remington, T., Sperling, L., & Turner, A. (2014). Seed storage brief #1: Defining seed quality and principles of seed storage in a smallholder context. Nairobi: Catholic Relief Services. Retrieved on 5 September 2018. https://www.crs.org/sites/default/files/tools-research/seed-storage-case- studies.pdf. Retrieved on 11 September 2018 223 Tables Table 8.1. The Initial MC of Seeds, and Storage Condition and Months Used in Seeds Storage. Final MC of Seeds Stored With or Without Zeolite Beads After 1, 3 and 6 Months of Storage. Initial Storage Final moisture content (%) moisture condition content (%) Month 1 Month 3 Month 6 c t c t c t Warm 9.8 8.5 9.8 8.5 9.8 8.8 9.8 Cold 9.9 8.3 9.8 8.7 9.8 8.7 Warm 11.3 8.8 11.3 9.0 11.3 8.9 11.3 Cold 11.2 8.6 11.3 9.1 11.3 8.9 Warm 15.5 6.7 15.6 6.5 16.3 6.6 15.3 Cold 15.3 6.8 15.8 6.2 16.4 6.4 c = seeds stored without zeolite beads, t = seeds stored with zeolite beads. Cold temperature = 18±1oC, warm temperature = 27±4oC. 224 225 226 Figures 120.0 9.8% Wt 100.0 9.8% Wc 9.8% Ct 80.0 9.8% Cc 11.3% Wt 60.0 11.3% Wc 11.3% Ct Percent germination germination Percent 11.3% Cc 40.0 15.3% Wt 15.3% Wc 20.0 15.3% Ct 15.3% Cc 0.0 0 2 4 6 8 Months of storage Figure 8.1. Percent Germination at 4 Days of All Seeds with Initial MC (%) Stored With or Without Zeolite Beads, and Stored for 1, 3, and 6 Months in Warm and Cold Temperatures. Wc = seeds stored without zeolite beads in a warm room, Wt = seeds stored with zeolite beads in a warm room, Cc = seeds stored without zeolite beads in a cold room, and Ct = seeds stored with zeolite beads in a cold room. Cold temperature = 18±1oC, warm temperature = 27±4oC. 227 120.0 9.8% Wt 9.8% Wc 100.0 9.8% Ct 9.8% Cc 80.0 11.3% Wt 11.3% Wc 60.0 11.3% Ct 11.3% Cc Percent germination germination Percent 40.0 15.3% Wt 15.3% Wc 20.0 15.3% Ct 15.3% Cc 0.0 0 2 4 6 8 Months of storage Figure 8.2. Percent Germination at 7 Days of All Seeds with Initial MC (%) Stored With or Without Zeolite Beads, and Stored for 1, 3, and 6 Months in Warm and Cold Temperatures. Wc = seeds stored without zeolite beads in a warm room, Wt = seeds stored with zeolite beads in a warm room, Cc = seeds stored without zeolite beads in a cold room, and Ct = seeds stored with zeolite beads in a cold room. Cold temperature = 18±1oC, warm temperature = 27±4oC. 228 CHAPTER 9. COST ASSESSMENT OF FIVE DIFFERENT MAIZE GRAIN HANDLING TECHNIQUES Modified from a manuscript to be submitted to the Applied Engineering in Agriculture Abstract Farmers in developing nations encounter high postharvest losses mainly attributable to the lack of modern techniques for threshing, cleaning, grading and storing of grains. Mechanized handling of grain in developing countries from threshing to storage is rare, although very expensive but very effective in keeping grain quality and quantity. This analysis was to obtain facts on the cost-effectiveness, and the possibility of making a profit based on different techniques of handling maize grain. The objective was to evaluate the cost-effectiveness of five grain handling techniques in regards to the conditions prevailing in Ghana. The cost-effectiveness of various maize grain handling techniques was computer simulated using windows excel spreadsheet, and the functional unit was handling 1 kg of maize grain. The high annual capital and operational costs of handling maize grain recorded using m. silo + acc. or m. silo could only be afforded through farmers- cooperatives. However, the capital cost and operational cost of using PICS or w. PP. + Phos. or w. PP. were very low, and most individual farmers could afford. The annual capital and operational costs decreased with an increasing scale of production. Handling grain with m. silo + acc. or m. silo demanded the sale of many units of grain to breakeven the expenses. Compared to m. silo + acc., a few units were required to breakeven using m. silo because of the low fixed cost and variable cost. Food security and financial prospects of farmers although a long-term could improve when grain is mechanically handled with m. silo + acc. or m. silo through farmers-cooperatives. Keyword: Cost analysis; maize grain; silo; PICS bag; phosphine; polypropylene bag. 229 9.1. Introduction Farmers in Ghana and other Sub-Saharan African (SSA) nations encounter high postharvest losses mainly attributable to the lack of modern techniques for threshing, cleaning, grading and storing of grains. Due to this, quantitative losses after harvest are estimated to be about 15%, 13% to 20%, and 15% to 25% respectively in the field, and during processing and storage (Abass et al., 2014). In support, the FAO (2011) indicated that 20%-30% of cereals are lost after harvest in most developing countries. Some studies have reported maize grain damage even up to 80% (De Groote, 2013; Chigoverah & Mvumi, 2016) which compare to my prior study which recorded 100% damage after six months of storage. Many farmers sell a larger proportion of their stocks a few weeks after harvest because they are constraint by income, debts, or limited good provision or place for storage (Stephens and Barrett, 2010). In reality, farmers can maintain or improve their grain quality and quantity if modern techniques of handling grain are adopted. The modern technique for handling grain include the use of mechanical threshers for grain shelling, gravity separators for cleaning and grading, solar tents for drying the grain, conveyors for the convenient conveyance of grain, and the use of airtight metal bins. Grain quality and quantity can be maintained so that farmers can gain substantial profits when grain price inflates. Efforts have been made to introduce some of the relatively inexpensive modern techniques to farmers in Africa. The use of hermetic containers and bags (jars or silos or PICS bags or GrainPro bags, etc.), locally made hermetic metal silos, insecticides (actellic super or phosphine, etc.). A combination of two or more of such methods had been studied and introduced to farmers in SSA (De Groote, 2013; Nganga et al., 2016; Purdue University, 2016; Mlambo et al., 2017; Baral & Hoffmann, 2018). In developing nations handling of grain using entirely 230 mechanized technology from threshing to storage is rare. Although very expensive but very effective in keeping grain safe in storage. To surmount any financial obstacle associated with the mechanized mean of grain handling, farmers can form cooperatives at local levels. This gives them a common voice as a first step to apply for financial credit. Individual farmers face a difficult task in an attempt to obtain financial credit from financial organizations in SSA, and Ghanaian farmers are not exempted. Nevertheless, the process becomes less cumbersome in the name of farmers-cooperatives. Empirical evidence of the significance of farmers-cooperatives in grain handling to persuade and encourage farmers is essential. This study was to obtain facts on capital and operational costs of various handling techniques, and the possibility of making a substantial profit based on the modern and conventional techniques of grain handling. Farmers can then partake in farmers-cooperatives if they have a fair idea on the importance and costs associated with modern techniques of grain handling (mechanized techniques). Therefore, this cost analysis aimed at evaluating the cost-effectiveness of five grain handling techniques in regards to the conditions prevailing in Ghana. This study was to serve as a blueprint for farmers to make decisions on whether to operate individually or as farmers-cooperatives. Importantly, to provide the government of Ghana a fair idea on good storage methods concerning the many agricultural flagship programs implemented. 9.2. Materials and Methods Computer simulation of the cost analysis of five grain handling techniques (methods) was done using windows excel spreadsheet. The five methods were metal silo plus all accessories (m. silo + acc.), metal silo only (m. silo), woven polypropylene plus phosphine (w. PP. + Phos.), woven polypropylene only (w. PP.), and PICS bags only 231 (PICS). All accessories comprise of a thresher, gravity separator, screw conveyor, and HDPE + UV solar tent dryer. 9.2.1. Goal and scope This analysis was to evaluate the cost-effectiveness of handling maize grain in Ghana using five storage techniques (in table 9.4). Based on the results farmers could decide to either (or not) be in cooperatives to enhance their food security and income security. It could also serve a similar purpose to Ghana’s government. Further scope highlights could be found in table 9.4. 9.2.2. System boundary The costs incurred by farmers during and after cultivation, and at pre-harvest and harvest were all excluded from the system boundary. The cost incurred during the transport of grain from farm to home (handling site) was also excluded. The system boundary for this analysis considered only the portions that figure 9.1 highlights. The losses considered were threshing to storage only. 9.2.3. Functional unit (FU) The FU of this study was handling 1 kg of maize grain. 9.2.4. Assumptions Harvested grain was brought home (handling site) for temporary (about a week) storage before threshing. The inflation rate and changes in the future exchange rate (cedi and dollar) in Ghana were not considered in the calculation. All the equipment were new and imported from China, and the cost of shipping was included in the analysis. 232 The initial MC (wet basis) of grain at harvest was 20%, then dried down to 13%, and this MC was used in the calculations. Other assumptions are found in tables 9.1-9.3. 9.2.5. Experimental design The independent variables and scenarios simulated could be found in table 9.4. In all 240 scenarios were studied, and the outputs were tabulated or graphically illustrated. 9.3. Results and Discussion 9.3.1. The annual capital and operational costs, and profits In figure 9.2 the grain was handled at a capacity of 2.8 Mg/year. The capital and operational costs of using metal silo plus all accessories (m. silo + acc.) during grain handling were extremely high, $1722.55/y and $37,864.57/y respectively. About $130.85/y and $2,552.54/y were recorded respectively as the capital and operational costs of using metal silo only (m. silo). Based on the usage of PICS bags only (PICS) a substantial reduction was observed in both the capital and operational costs, which were $1.12/y and $63.27/y respectively. Similar lower costs trend was recorded using woven polypropylene plus phosphine (w. PP. + Phos.), and woven polypropylene only (w. PP.). The capital and operational costs of handling grain with w. PP. + Phos. were $1.05/y and $91.92/y, and capital and operational costs of handling grain with w. PP. were $0.63/y and $58.32/y respectively. Yearly profits margin ($/y) recorded handling grain with m. silo + acc. were negative even when the price of maize was increased to 70% (-$38,353.98/y). Grain handling using m. silo recorded a yearly negative profit at even 70% increase in the price of maize (-$1672.09/y). However, handling grain using PICS or w. PP. + Phos. or w. PP. recorded positive yearly profits. The yearly profits increased with the estimated 233 increases in maize price. At no price increase, w. PP. recorded the highest profit of $524.48/y, and was followed closely by PICS ($519.11/y), and w. PP. + Phos. ($490.52/y). In figure 9.3, the handling capacity was increased to 14 Mg/year. The yearly capital costs remained the same as in 2.8 Mg/year for all the five handling methods. Nevertheless, increases in yearly operational costs were recorded. Handling of grain using m. silo + acc., m. silo, w. PP. + Phos., PICS, and w. PP. respectively recorded increases of $38.19/y, $19.99/y, $9.58/y, $6.38/y and $6.38/y above the operational costs incurred in 2.8 Mg/year. Except for the handling of grain with m. silo + acc., all the rest recorded positive profits even without any estimated maize price increase. Importantly, the reduction in the negative yearly profit by $2,295.14/y using m. silo + acc. should be acknowledged. The yearly increase in profits (at no grain price increase) recorded above the 2.8 Mg/y handling capacity were $2,313.35/y, $2,326.95/y, $2,323.76/y, and $2,326.95/y, respectively for m. silo, PICS, w. PP. + Phos., and w. PP. The estimated increases in grain prices from 30% to 70% resulted in corresponding increases in profits in a similar trend in all the five handling methods. In figure 9.4, the handling capacity was increased to 28 Mg/year. Capital costs remained the same. There were slight increases in operational costs compared to that in the 14 Mg/year capacity. The additional increases in operational costs were $47.74/y, $24.99/y, $11.97/y, $7.98/y, and $7.98/y respectively associated with grain handling using m. silo + acc., m. silo, w. PP. + Phos., PICS, and w. PP. Yearly profits similarly increased and have been reported in decreasing order of w. PP. ($5,760.11/y), PICS ($5,754.75/y), w. PP. + Phos. ($5,718.98/y), m. silo ($3,124.59/y), and m. silo + acc. (-$33,598.24/y). 234 Based on the capital cost and operational cost analysis, handling maize grain with m. silo + acc. was very expensive compared to using m. silo. The total costs (sum of capital and operational costs) of handling grain using either m. silo + acc. or m. silo would be beyond the financial capability of any single individual smallholder farmer in a developing nation. Good storage systems demand huge capital and technical skills (Edwards, 2015) which are impracticable to smallholder farmers. However, the capital and operation costs of handling grain with PICS or w. PP. + Phos or w. PP. were within the financial capabilities of smallholder farmers. None of the three latter handling methods exceeded 0.08% of the capital costs and 0.3% of the operational costs of handling grain with m. silo + acc. Farmers would start making profits on their sales even at capacity as low as 2.8 Mg handling grain with PICS, w. PP. + Phos, and w. PP. The profits decreased from handling grains with w. PP., PICS to w. PP. + Phos. To overcome the financial challenges associated with handling grain using m. silo or m. silo + acc., farmers could come together to form farmers-cooperatives. Farmers-cooperatives help increase productions and incomes of members through the possibility of accessing financial credits, agricultural inputs, information, and markets (ATA, 2015). The cooperative could engross the operational and capital costs, and this helps to have equity capital and debt capital to begin, and also to contract loans from financial institutions. According to the USDA (1994), equity capital refers to ownership capital provided by members in a cooperative, and the money that is borrowed is debt capital. The study by Francesconi et al. (2015) indicated that agricultural- cooperations fortify the power of smallholder farmers to bargain either for loans or good grain market price. As reported in the agriculture for impact (2018), a maize growing association in Ghana (Masara N’Arziki) started between 2008 and 2012 is now a mammoth 235 association in West Africa with estimated revenue of US$369.00 per farmer per hectare in 2012. Cooperatives could increase farmers handling capacity to make profits as quickly as possible. Alongside the financial benefits members also benefit from the improved product, service quality, reduced risks, social and economic empowerment through the ability to partake in decision-making processes. Increased participation in Farmer Field School (FFS) in Kenya, Uganda, and Tanzania in 2010 resulted in improved crop productivity, production, and income (FAO, 2012). The available marketing opportunities increase for storing grain beyond harvest. However, the choice of handling or storage method is highly dependent on the relative cost of the method and how feasible regarding the overall harvesting, handling, and marketing system (Edwards, 2015). 9.3.2. The annual capital and operational costs, and profits at percentage grain losses In figure 9.5, the capital and operation costs remained the same as were recorded in figure 9.2 with regards to m. silo + acc., m. silo, w. PP. + Phos., w. PP., and PICS. The m. silo + acc. and m. silo upon subjection to losses in grain quantity of 0%, 1%, 5%, and 7%, the corresponding yearly profits were all in the negatives (although in increasing order of % reduction in quantity). However, the negative values ($) at zero percent loss in grain quantity were fairly better. Similarly, yearly profits recorded by handling grain with w. PP. + Phos. or w. PP. or PICS although positive, the profits reduced correspondingly with the increasing percentages of losses in grain quantity from 0%, 4%, 15%, to 30%. Figures 9.6 and 9.7 correspond respectively to figures 9.3 and 9.4 concerning the capital and operational costs which remained the same. Similar trends of negative profits were recorded when m. silo + acc was used, but much better because of the increased in handling 236 capacity. The m. silo at this point recorded profits (positive) like that of w. PP. + Phos., w. PP., and PICS irrespective of the percentage losses in grain quantity. Despite the expensive nature of handling grain with m. silo + acc., there are many significant advantages over the other methods including maintaining grain quality and quantity with loses below 7%. Generally, grain elevators experience less than 1% loss during storage and handling, and about 1.4% normal shrinks (Hurburgh, 2009; Carlson & Reese, 2016) which are below the estimated percentage losses used in this study. Hermetic storage bins are more voluminous compared to self-built silos (locally made), and grain should have safe MC before storage. The effectiveness of most locally built metal silos (m. silo) has been tried in many studies, and maize grain weight loss experienced was minimal and relatively close to that of m. silo + acc. Negligible (Fischler et al., 2011), 0.28% (Mlambo et al., 2017), 1.8% (De Groote et al., 2013), and less than 7% (Chigoverah & Mvumi, 2016) maize grain weight losses have been associated with using m. silo to store grain for at least 6 months. Grain stored in PICS could experience grain losses between 4% and 12% (Chigoverah & Mvumi, 2016; De Groote et al., 2013; Ndegwa et al., 2016). Commonly, the percentage of grain weight loss was between 0% and 0.31% (Hell et al., 2010; Ndegwa et al., 2016; Nganga et al., 2016; Mlambo et al., 2017; Baral & Hoffmann, 2018). In contrast, the percentage of grain quantity loss encountered using w. PP. could be up to 33.8% (De Groote et al., 2013), 17.95% (Hell et al., 2010), and 15% (Baral & Hoffmann, 2018). But there could be some exceptions as Ndegwa et al. (2016), and Nganga et al. (2016) revealed 2.4% and 0% losses respectively. The efficacy of w. PP. + Phos. (or different insecticides) closely relates to PICS as between 0.03% and 12.3% losses normally 237 happen, although 34% or more have been reported (Chigoverah & Mvumi, 2016; De Groote et al., 2013; Ndegwa et al., 2016; Mlambo et al., 2017; Baral & Hoffmann, 2018). Hermetic storage (bag or m. silo) have demonstrated superiority in preventing insects infestation and grain damage, and losses in stored maize grain, although insecticides could be equally effective (Chigoverah & Mvumi, 2016; Mlambo et al., 2017). Nevertheless, the low operational costs and high yearly profits accrued using PICS surpass that of W. PP. + Phos. or w. PP., hence economically practicable for farmers that cannot purchase m. silo. The m. silo protects grain against harsh climate, and infestation by insects, pests, and mold (Tefera et al., 2011; Edwards, 2015). Comparatively w. PP. + Phos., w. PP., and PICS are susceptible to harsh weather, insects, pests, and sometimes molds, and relatively have short life cycles. PICS bags are much efficient in reducing grain losses compared to w. PP. under similar storage conditions (Baributsa et al., 2010; Baoua et al., 2013). However, hermetic bags could get damaged due to punctures from sharp end objects, or be abraded or perforated by rodents and insects (De Groote et al., 2013; García-Lara et al., 2013). Both w. PP. and PICS could burst during handling or transport and lose their usefulness, and subsequently results in extra financial burden to farmers. Synthetic insecticides are expensive, may be ineffective or adulterated or rare in the markets, and known to have detrimental health and environmental effects (Addo et al., 2002; Njoroge et al., 2014). The results of this current analysis closely compare to earlier studies which used w. PP. + Phos., w. PP., and PICS regarding profit making. But using PICS has many advantages including 3-4 years reusability which results in reduced operational costs compared to using w. PP. + Phos. or w. PP. Jones et al. (2011) and Baral & Hoffmann (2018) reiterated the dramatic increase in profit when storage was extended to eight months 238 in wait for a maximum price. In their study the use of PICS, and w. PP. + insecticide (Sofagrain) recorded positive returns on storage compared to w. PP. (without insecticides). Worth noting was the high returns on PICS storage due to its reusability even though the capital cost was high compared to operation cost (low). Abass et al. (2014) estimated that due to the lack of mechanized grain handling techniques in developing countries grain quantitative losses of about 13% to 20%, and 15% to 25% happen during processing and storage respectively. The huge postharvest losses experienced in developing countries are greatly attributable to the absence of good techniques to separate foreign particles and debris, and damaged or unhealthy grain (diseased and insects or mold infested grain) before storage. In spite of the costly capital and operational costs of handling grain using m. silo + acc. (mechanized), the fact that it could reduce losses in grain quantity and quality makes it a no-brainer. M. silo + acc. could maintain grain quality and quantity in storage, and could also contribute to improved food security and income of farmers. Manandhar et al. (2018) further asserted that the use of w. PP. resulted in low quality and high loss in grain, w. PP. + Insecticide led to low grain quality and loss, while PICS ensured high grain quality and low loss. Reasonably, amidst the enormous benefits associated with using PICS, it had the lowest operational cost, and the capital cost was slightly high. It would be appropriate for the government of Ghana to initiate the use of m. silo + acc. in grain handling. This is because of the government’s many agricultural flagship programs including planting for food and jobs, planting for export and rural development, and etc. 239 9.3.3. Economies of scale of capital and operational costs Figures 9.8 to 9.12 show the economies of scale of capital and operational costs of handling maize grain using the five handling methods (m. silo + acc., m. silo, w. PP. + Phos., w. PP., and PICS). As it was anticipated the capital and operational costs ($/Mg/y) decreased drastically with the increased handling capacity from 2.8 Mg, 14 Mg to 28 Mg. Among the five handling methods, the use of w. PP. recorded the lowest capital and operational costs at each handling capacity. Grain handling with m. silo had capital and operational costs ($/Mg/y) less than 9% of that of m. silo + acc. across the 2.8 Mg to 28 Mg capacity. The capital and operational costs required using PICS, w. PP. + Phos., and w. PP. respectively recorded less than 0.1% and 0.3% of using m. silo + acc. across the 2.8 Mg to 28 Mg capacity. However, PICS, w. PP. + Phos., and w. PP. recorded less than 1% and 3% of the capital and operational costs of using m. silo across the 2.8 Mg to 28 Mg capacity. Capital and operational costs of w. PP. + Phos. were about 36% higher than that of w. PP. across the 2.8 Mg to 28 Mg capacity. While the capital cost of PICS was about 7% higher than that of w. PP. + Phos. and the operational cost of PICS was 31% less than that of w. PP + Phos. across the 2.8 Mg to 28 Mg capacity. The capital cost of PICS was about 44% higher than that of w. PP. and the operational cost of PICS was about 9% less than that of w. PP. across the 2.8 Mg to 28 Mg capacity. Economies of scale is a way to maximize production and minimize the cost of production in business. Hence, economies of scale is the competitive advantage that large- scale production has over small-scale production. The larger the scale of production the lower the per-unit costs, as the average costs can be spread over more production units 240 (Amadeo, 2017). There is an increase in total cost as output increases, but the average cost of producing each unit falls simultaneously. Economies of scale is a significant facet of effectiveness in production (WJEC-UK, 2015). The capital and operational costs of m. silo + acc. and m. silo despite been very high and beyond the financial limits of farmers, the average cost decreased with the increased handling capacity. Since the average cost decreased with the increasing capacity many members constituting a farmers-cooperative, and the members when they increase their handling capacity could be essential in overcoming a considerable portion of the financial challenges. The importance of farmers- cooperatives has been highlighted already, and it would be prudent for farmers to form cooperatives rather than operating individually. Moreover, due to financial constraints, individual farmers could explore the option of using PICS rather than w. PP. + Phos. or w. PP. Farmers could increase their production scale to benefit from economies of scale, and this could help farmers accrue considerable profits. 9.3.4. Breakeven points (in units) Figure 9.13 shows the breakeven points of handling maize grain using m. silo + acc., m. silo, w. PP. + Phos., w. PP., and PICS. In all these situations the units (the quantity of a particular handling capacity needed to breakeven) of breakeven point decreased with the increased handling capacity. A drastic reduction from 74.20 units (at 2.8 Mg capacity) to 13.47 units (at 14 Mg capacity) was achieved handling grain with m. silo + acc. About 7 units (at 28 Mg capacity) were required to reach the breakeven point. When grain was handled with m. silo, the breakeven point was reached at 14 Mg capacity. At 2.8 Mg capacity, only 4.5 units were required to breakeven. Noteworthy, when grain was handled with w. PP. + acc., w. PP., and PICS, the breakeven point was attained at 2.8 Mg capacity. 241 A breakeven point is reached when the total revenue is equal to total cost. Profit is zero at this point, but no money is lost. Revenue depends on the number of units sold. In general, revenue increases with an increasing number of units (George Brown College, 2014; Berry, 2018). It was fast to attained breakeven point using w. PP. + acc., w. PP., and PICS even when the capacity was not increased. Hence, increasing capacity becomes an added advantage to farmers to make profits as quickly as possible. Handling of grain using m. silo + acc. was greatly demanding to reach the breakeven point. Continuous production capacity at 2.8 Mg/year or 28 Mg/year demands 74 years or 7 years respectively to reach the breakeven point. To quickly attain breakeven point requires an increase in the production unit per year, or an increase in the unit selling price or the average fixed and variable costs should be reduced. According to Peavler (2018) to reach a breakeven point either the price of the product is raised or the fixed and variable costs are reduced. The breakeven points demanded higher production units using m. silo + acc., and m. silo because the fixed and variable costs were high compared to that of w. PP. + acc., w. PP., and PICS. Estimating the breakeven point is an essential first step, and it has been considered in this study. 9.4. Conclusions The annual capital cost and operational cost of handling maize grain with m. silo + acc., and m. silo were very high, and farmers could only afford the costs by forming farmers-cooperatives. This could enhance their chances of accessing financial credits from banks, and also accumulate the required equity capital. Alternatively, the capital cost and operational cost of grain handling using PICS, w. PP. + Phos., and w. PP were essentially low and within the financial capabilities of individual smallholder farmers. We should not overlook the high losses in grain quality and quantity, and the low quality and small 242 quantity losses associated with grain handling using w. PP., and w. PP. + Phos. In this instance, grain handling using PICS is superior (high grain quality and quantity) despite the relatively slight increase in capital cost. Nonetheless, it had the lowest operational cost. Mechanized handling of grain (m. silo + acc.) should have been the best option as it has a high ability to maintain grain quality and quantity, but due to financial constraints, farmers on an individual basis could opt for PICS. The annual capital and operational costs decreased with the increased in production scale (economies of scale). It is significant that farmers increase their production capacity to make a considerable profit. Handling grain with m. silo + acc. or m. silo demanded the sale of many units (the quantity of a particular handling capacity needed to breakeven) of grain to reach the breakeven point. However, the number of units reduced as the production capacity was increased. On the contrary, to reach the breakeven point using m. silo, a fewer production unit was needed as the fixed and variable costs were lower than that of m. silo + acc. Even at the lowest capacity of 2.8 Mg, the breakeven point was attained using PICS, w. PP., and w. PP. + Phos. Predictably, increasing handling capacity increases the profit margin of farmers, however the high percentage grain weight loss mostly related to the use of w. PP., and w. PP. + Phos. should be not be disregarded. Food security and financial prospects of farmers although a long-term could be high if maize grain is handled with m. silo + acc. or m. silo through farmers-cooperatives. That notwithstanding, individual farmers could equally improve their food security and financial security by choosing PICS (or other airtight bags) rather than w. PP. or w. PP. + Phos. The government of Ghana should initiate the application of m. silo + acc. in grain handling to complement the success of the many agricultural flagship programs. 243 9.5. References Abass, A. B., Ndunguru, G., Mamiro, P., Alenkhe, B., Mlingi, N., & Bekunda, M. (2014). Post-harvest food losses in maize-based farming system of semi-arid savannah area of Tanzania. J. Stored Prod. Res., 57, 49-57. Addo, S., Birkinshaw, L. A., & Hodges, R. J. (2002). Ten years after the arrival in Ghana of Larger Grain Borer: farmers' responses and adoption of IPM strategies. Int J Pest Ma., 48, 315-325. Agriculture for Impact. (2018). Agricultural Cooperatives. Case Studies: Cooperatives- Ghana Grain Partnership. https://ag4impact.org/wp- content/uploads/2015/07/Cooperatives-Case-Studies.pdf. Retrieved on 16 Nov. 2018. Amadeo, K. (2017). Economies of Scale. TheBalance.com. October 27, 2018. https://www.thebalance.com/economies-of-scale-3305926. Retrieved on 12 November 2018. ATA. (2015). Ethiopian Agricultural Transformation Agency (ATA). Agricultural Cooperatives Sector Development Strategy 2012-2016. http://www.ata.gov.et/download/agricultural-cooperative-sector-development- strategy-2012-2016/. Retrieved on 2 November 2018. Baral, S., & Hoffmann, V. (2018). Tackling post-harvest loss in Ghana: Cost-effectiveness of technologies. International Food Policy Research Institute Working Paper, March 2018, pp.1–8. http://books.google.com/. Retrieved on 1 November 2018. Baributsa, D., Lowenberg-DeBoer, J., Murdock, L. L., & Moussa, B. (2010). Profitable chemical-free cowpea storage technology for smallholder farmers in Africa: Opportunities and challenges. Julius Kühn Arch., 425, 1046–1052. Baoua, I. B., Amadou, L., Lowenberg-Deboer, J. D., & Murdock, L. L. (2013). Side by side comparison of GrainPro and PICS bags for postharvest preservation of cowpea grain in Niger. J. Stored Prod. Res., 54, 13–16. Berry, T. (2018). What is a break-even analysis?. Bplans.com. https://articles.bplans.com/break-even-analysis/. Retrieved on 18 November 2018. Carlson, C. G., & Reese, C. L. (2016). Grain marketing - Understanding corn moisture content, shrinkage, and drying. In Clay, D. E., C. G. Carlson, S. A. Clay, & E. Byamukama (Eds.), iGrow Corn: Best management practices (Chapter 35, pp. 1-8). South Dakota State University. www.iGrow.org. Chigoverah, A. A., & Mvumi, B. M. (2016). Efficacy of metal silos and hermetic bags against stored-maize insect pests under simulated smallholder farmer conditions. J. Stored Prod. Res., 69, 179–189. 244 De Groote, H., Kimenju, S. C., Likhayo, P., Kanampiu, F., Tefera, T., & Hellin, J. (2013). Effectiveness of hermetic systems in controlling maize storage pests in Kenya. J. Stored Prod. Res., 53, 27-36. Edwards, W. (2015). 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A policy note on agricultural cooperatives in Africa. Enhancing development through cooperatives (EDC)-Action research for inclusive agribusiness. CIAT Policy Brief No. 26. Centro Internacional de Agricultura Tropical (CIAT), Cali, Colombia., pp. 1-6. García-Lara, S., Ortíz-Islas, S., & Villers, P. (2013). Portable hermetic storage bag resistant to Prostephanus truncatus, Rhyzopertha dominica, and Callosobruchus maculatus. J. Stored Prod. Res., 54, 23–25. George Brown College. (2014). Breakeven point analysis. Educational Ressources: Tutoring and Learning Center, pp.1–3. www.georgebrown.ca/tlc. Retrieved on 10 November 2018. Hell, K., Ognakossan, K. E., Tonou, A. K., Lamboni, Y., Adabe, K. E., & Coulibaly, O. (2010). Maize stored pests control by PICS-Bags : Technological and Economic Evaluation. IITA 5th World Cowpea Conference in Saly, Senegal 27, September - 1 October 2010, pp.1–8. Hurburgh, C. R. (2009). Integrated crop management: A tough harvest-frequently asked questions. Extension and outreach, Iowa State University, Ames, Iowa, USA. https://crops.extension.iastate.edu/cropnews/2009/11/tough-harvest-frequently- asked-questions. Retrieved on 15 November 2018. 245 Jones, M., Alexander, C., & Lowenberg-DeBoer, J. (2011). An initial investigation of the potential for hermetic Purdue improved cowpea storage (PICS) bags to improve incomes for maize producers in Sub-Saharan Africa. Working paper #11-3 (September), Dept. of Agricultural Economics, Purdue University, pp. 1-6. https://www.researchgate.net/publication/270568951%0AAN. Retrieved on 5 November 2018. Manandhar, A., Milindi, P., & Shah, A. (2018). An overview of the post-harvest grain storage practices of smallholder farmers in developing countries. Agriculture, 8(57), 1-21. Mlambo, S., Mvumi, B. M., Stathers, T., Mubayiwa, M., & Nyabako, T. (2017). Field efficacy of hermetic and other maize grain storage options under smallholder farmer management. Crop Prot., 98, 198–210. Ndegwa, M. K., De Groote, H., Gitonga, Z. M., & Bruce, A. Y. (2016). Effectiveness and economics of hermetic bags for maize storage: Results of a randomized controlled trial in Kenya. Crop Prot., 90, 17–26. Nganga, J., Mutungi, C., Imathiu, S., & Affognon, H. (2016). Effect of triple-layer hermetic bagging on mold infection and aflatoxin contamination of maize during multi-month on-farm storage in Kenya. J. Stored Prod. Res., 69, 119–128. Njoroge, A. W., Affognon, H. D., Mutungi, C. M., Manono, J., Lamuka, P. O., & Murdock, L. L. (2014).Triple bag hermetic storage delivers a lethal punch to Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae) in stored maize. J. Stored Prod. Res., 58, 12-19. Peavler, R. (2018). Use this formula to calculate a breakeven point. The balance small business. https://www.thebalancesmb.com/how-to-calculate-breakeven-point- 393469. Retrieved on 17 November 2018. Purdue University. (2016). PICS. Newsletter Vol. 2 issue 1. Department of Entomology. Purdue, Indiana, USA, pp. 1-5. Stephens, E. C., & Barrett, C. B. (2010). Incomplete Credit Markets and Commodity Marketing Behavior. Cornell University Working Paper. Pitzer College, 1050 N. Mills Ave., Claremont, CA 91711. Pp. 1-40. http://barrett.dyson.cornell.edu/Papers/JAE%20resub%20Apr%202010%20with%20 title%20page.pdf. Retrieved on 17 November 2018. Tefera, T., Kanampiu, F., De Groote, H., Hellin, J., Mugo, S., Kimenju, S.… Banziger, M. (2011). The metal silo: An effective grain storage technology for reducing post- harvest insect and pathogen losses in maize while improving smallholder farmers’ food security in developing countries. Crop Prot., 30, 240–245. 246 USDA. (1994). United States Department of Agriculture Rural Development. Understanding cooperatives: Financing cooperatives. Cooperative information report 45, Section 7, October 1994. http://www.rurdev. http://www.rurdev.usda.gov/rbs/pub/cooprpts.htm. Retrieved on 17 November 2018. WJEC-UK (2015). Economies of scale. Chapter 31, pp. 1-6. http://resource.download.wjec.co.uk.s3.amazonaws.com/vtc/2015-16/WJEC-15- 16_06/pdf/eng/business-functions/chapter31.pdf. Retrieved on 16 November 2018. 247 Tables Table 9.1. The Specifications and Prices of Equipment and Materials Used in the Cost- Analysis. Equipment/Materials Features Average Unit Source Cost (US$) HDPE +UV Solar tent (15 m*3.6 m)* 2 = 1,420.4 dryer (2 units bought) 108 m2, Lifespan: 25 years Thresher (1 unit 9 Mg/hour, 4.5 800.0 bought) kWh, Lifespan: 25 years Gravity separator (1 3.63 Mg/hour, 2.2 14,550.0 unit bought) kWh, Lifespan: 25 Alibaba.com. years Retrieved on Screw conveyor (1 0.1 Mg/h, 1.5 kWh, 1,500.0 October 2018 unit bought) up to 45° elbows, Lifespan: 25 years Metal silo (1 unit 28 Mg, Lifespan: 3,500.0 bought) 25 years, bottom hopper Rubber 1 Mg/year, 15.0 lifespan: 1 year Woven polypropylene 1 Mg/year, 10.4 Personal inquiry bags lifespan: 1 year Phosphine tablets 1 Mg/year, 16.7 Applied every 3 months/year Hermetic (PICS) bags 1 Mg/year, 30.0 Nouhoheflin et al. ( lifespan: 2-4 years 2017); NRI- (3 years used) University of Greenwich (2014) 248 Table 9.2. Assumptions on Utility and Services Costs, and Some Parameters Used in the Cost-Analysis. Utility/services Estimates Cost (US$ References or %) Electricity price (EP) 1 kWh 0.06 https://www.globalpetrol prices.com/electricity_pri ces/ Labor cost Per day 2.02 https://mywage.org/ghana /salary/minimum-wages/ Operational hours of 56 hours/year or 2 i.e. equipment (OH) hours/day for 28 $14.14/year Personal estimation days person Number of hired Two persons for laborers using m. silo + Personal estimation (Most activities to be acc., and 1 person carried out by farmers) for the others Interest rate (I) 17% http://www.bog.gov.gh/m arkets/interbank-interest- rates/daily-depo-rates. Monthly installment 60 months (N) Insurance rate 15%-23% 10% Antwi-Boasiako, B. A. (2017) Tax (cooperate) 25% http://gra.gov.gh/index.ph p/income-tax/ Tax (personal) 7.5% Ghana cedi/dollar rate GHȻ4.8 1 http://www.bog.gov.gh/m arkets/interbank-interest- rates/daily-depo-rates. Wiring & controls cost Percentage of total 4% (C2) capital cost of ABE 580 (Engineering equipment (CP) Analysis of Biological Percentage of 40% Systems), ISU total capital cost Installation (C3) of equipment (CP) 75% Motor efficiency Percentage of total 10% Equipment freight capital cost of Personal estimation (C4) equipment (CP) 249 Table 9.3. Equations Used in the Cost-Analysis Calculations. Analyses (units included) Equations (units included) g Mg/d------(9.1) G (Mg/y) g (Mg/d)*OH (h/y)/(X h/d)------(9.2) Annuity N N A = P (I (1+I) )/((1+I) -1)) ------(9.3) Equipment initial cost (CP), ($) Ʃ (purchase price of each piece of equipment)----- (9.4) Total equipment initial cost (C5), ($) Ʃ (CP + C2 + C3 + C4)------(9.5) Total building cost (C6), ($) Building space (ft2)* 12.5 (Building construction cost, $/ft2)------(9.6) Engineering and design cost (C7), ($) 7% of Ʃ (C5 + C6)------(9.7) Electricity consumed (E1), motor load (kW- Connected load*OH/ 0.75------(9.8) h/y) Total electricity cost (C8), ($/y) E1 * EP------(9.9) Equipment salvage value (ESV), ($) 15% of Ʃ (C5 + C6 )------(9.10) Yearly sales of the product ($) The unit price of product*quantity on sale------(9.11) Total Annualized Benefits (TAB), ($/y) (Annualize ESV + yearly sales of a product)------(9.12) Annualized capital costs (AFC1), ($/y) Annualized (Ʃ(C5 + C6 + C7))------(9.13) Cost basis of fixed asset‐Salvage value Annual straight-line depreciation (AFC2), ------(9.14) ($/y) Estimated useful life Insurance (AFC3), ($/y) 10/100 * (C5 + C6) ------(9.15) Interest (AFC4), ($/y) 17/100* (C5 + C6)------(9.16) Overhead (AFC5), ($/y) 0.16 ($/Mg) * G (Mg/y)------(9.17) Taxes (AFC6), ($/y) Cooperate = 25/100* (C5 + C6) ------(9.18) Individual = 7.5/100 * (C5 + C6) Total annual fixed costs (TAFC), ($/y) Ʃ (AFC1 + AFC2 + AFC3 + AFC4 + AFC5 + AFC6)------(9.19) Electricity (AVC1), ($/y) C8 Labor (AVC2), ($/y) 0.2525 ($/labor h) *56 (operation h/y)*2 (laborers)------(9.20) Maintenance & repairs (AVC3), ($/y) 2 ($/Mg) * G (Mg/y)------(9.21) Misc. supplies AVC4), ($/y) 1 ($/Mg) * G (Mg/y)------(9.22) Other (AVC5), ($/y) 0.25 ($/Mg) * G (Mg/y)------(9.23) Total annual variable costs (TAVC), ($/y) Ʃ (AVC1 + AVC2 + AVC3 + AVC4 + AVC5)--(9.24) Total yearly Profit ($/y) TAB - (AFC1+ TAFC+ TAVC)------(9.25) Economies of scale ($/Mg/y)/Mg The capital or operational costs ($/Mg/y)/storage capacity (Mg)------(9.26) Breakeven point (units) [(Annual fixed cost)/(Annual sale – Annual variable cost)]------(9.27) 250 Table 9.4. Experimental Design and Parameters Used in the Cost-Analysis. Independent References for the Variables Scenarios assumptions 1. Metal silo/thresher/gravity separator/ screw conveyor/HDPE + UV Solar Grain handling and tent dryer Personal assumption storage methods (5) 2. metal silos/rubber 3. Hermetic bag/rubber 4. Insecticides (Phosphine tablet)/ polypropylene/rubber 5. Polypropylene/rubber Grain storage capacity 2.8 (3) in Mg 14 Personal assumption 28 Estimated Losses in Hodges (2001); Compton grain quantity/quality 0% to 7% grain loss for metal and Sherrington (1999); (4) silo + acc., and metal silo only. De Groote (2013); Ndegwa et al. (2015); 0% to 30% grain loss for woven Chigoverah (2016); Baral PP only, woven PP + and Hoffmann (2018); Phosphine, PICS bags only. Fischler et al. (2011). 0% Personal assumption Estimated price 30% increase of grain (4) 50% 70% 251 Figures Courtesy of Courtesy of Green www.alibaba.com World Investor Courtesy of www.grainssilo.com Modern/ advanced handling Technology Thresher Separator Solar Drying Tent Screw Conveyor Hermetic Bin Courtesy of MIT, 2015 Maize Grain Ready for Sale Courtesy of MARK EDWARDS, Hard Rain conventiona l/less advanced handling Methods Temporary Storage Structure Floor Drying Improvised Shelling of Grain Grain in Hermetic & Polypropylene Bags Figure 9.1. System Boundary for the Cost-Analysis of the Various Handling Methods . 252 253 254 255 256 257 258 Capital cost ($/Mg/y) Operational cost ($/Mg/y) Power (Capital cost ($/Mg/y)) Power (Operational cost ($/Mg/y)) 13523.06 y = 13022x-2.118 R² = 0.9942 2707.34 Capital and operational ($/Mg/y) costs operational and Capital -2.12 y = 592.44x 1355.38 R² = 0.9943 615.20 123.04 61.52 2.8 14 28 METAL SILO & ACCESSORIES Storage capacity (Mg) Figure 9.8. Economies of Scale of Capital and Operational Costs ($/Mg/y) of Using Metal Silo and All Accessories. 259 Capital cost ($/Mg/y) Operational cost ($/Mg/y) Power (Capital cost ($/Mg/y)) Power (Operational cost ($/Mg/y)) 911.62 y = 877.22x-2.105 R² = 0.9939 Capital and operational ($/Mg/y) costs operational and Capital 183.75 y = 45.003x-2.12 R² = 0.9943 92.77 46.73 9.35 4.67 2.8 14 28 METAL SILO Storage capacity (Mg) Figure 9.9. Economies of Scale of Capital and Operational Costs ($/Mg/y) of Using Metal Silo Only. 260 Capital cost ($/Mg/y) Operational cost ($/Mg/y) Power (Capital cost ($/Mg/y)) Power (Operational cost ($/Mg/y)) 22.60 ) /Mg/y ($ y = 21.589x-1.939 R² = 0.99 4.98 Capital and operational costs operational and Capital y = 0.3846x-2.12 2.77 R² = 0.9943 0.40 0.08 0.04 2.8 14 28 P ICS BAGS Storage capacity (Mg) Figure 9.10. Economies of Scale of Capital and Operational Costs ($/Mg/y) of Using PICS Bags Only. 261 Capital cost ($/Mg/y) Operational cost ($/Mg/y) Power (Capital cost ($/Mg/y)) Power (Operational cost ($/Mg/y)) 32.83 ) /Mg/y ($ y = 31.36x-1.934 R² = 0.9899 Capital and operational costs operational and Capital 7.25 4.05 y = 0.3596x-2.12 R² = 0.9943 0.37 0.07 0.04 2.8 14 28 WOVEN PP BAGS & PHOSPHINE Storage capacity (Mg) Figure 9.11. Economies of Scale of Capital and Operational Costs ($/Mg/y) of Using Woven Polypropylene Bags and Phosphine Tablets. 262 Capital cost ($/Mg/y) Operational cost ($/Mg/y) Power (Capital cost ($/Mg/y)) Power (Operational cost ($/Mg/y)) 20.83 y = 19.89x-1.925 R² = 0.9896 4.62 Capital and operational ($/Mg/y) costs operational and Capital 2.60 y = 0.2171x-2.12 R² = 0.9943 0.23 0.05 0.02 2.8 14 28 WOVEN PP BAGS Storage capacity (Mg) Figure 9.12. Economies of Scale of Capital and Operational Costs ($/Mg/y) of Using Woven Polypropylene Bags Only. 263 Metal silo & Acc Metal silo Woven PP bags & Phos Woven PP bags PICS bags Power (Metal silo & Acc) Power (Metal silo ) 74.20 y = 70.963x-2.223 R² = 0.9927 Breakeven point(Unit) Breakeven y = 4.3152x-2.14 13.47 R² = 0.9939 6.66 4.49 0.88 0.44 0.09 0.06 0.05 0.02 0.01 0.01 0.01 0.01 0.01 2.8 14 28 Handling capacity per year (Mg/y) Figure 9.13. Breakeven Point Units (The Quantity of a Particular Handling Capacity Needed to Breakeven) of Each Handling Method Per Handling Capacity (Year). 264 CHAPTER 10. GENERAL CONCLUSIONS, RECOMMENDATIONS, AND FUTURE RESEARCH WORK 10.1. General Conclusions Controlling seed or grain moisture, oxygen, temperature, and RH in storage are very important since they influence viability and deterioration. Grain MC equilibrated with air moisture during storage resulting in increased grain final MC in non-hermetic jars. At 15oC, respiratory and metabolic activities reduced, and hence grain MC was maintained in hermetic jars. Grain MC increased in airtight jars at 20oC and 30oC. The oxygen concentration depleted in the airtight jars, and CO2 increased. S. zeamais mortality was 100% in airtight jars, but 3% to 87% in non-hermetic jars. The loss in grain weight increased at 30oC with increased temperature in non-hermetic jars. The grains were stored safely in airtight jars compared to non-airtight jars, especially at low temperatures. Farmers in SSA who cannot afford grain refrigeration should first dry down grain to low MC before storing in airtight jars at relatively low temperature and RH. Seeds resistant to S. zeamais can be cultivated. In the environmental assessment of the usage of actellic super and NeemAzal, pirimiphos-methyl manufacturing and transport had low CO2 eq.kg/kg emissions and impacts (mPts/kg) compared to permethrin manufacturing only. Importantly, sea transport of pirimiphos-methyl and permethrin recorded low CO2 eq.kg/kg emissions and impacts compared to air transport, hence, sea transport is encouraged to reduce GHG emission effects and global warming. Pirimiphos-methyl had the highest ecotoxicity and human health impacts. However, azadirachtin had no human health impacts. This study affirms the assertion that azadirachtin (NeemAzal) is specific to the target organism, and farmers can, therefore, use without health concerns. Despite the smaller mass of permethrin used, 265 when the ecotoxicity and human health impacts are compared to azadirachtin and pirimiphos-methyl, permethrin usage cannot be considered friendly environmentally and healthwise. If permethrin had been used in a larger mass as azadirachtin, ecotoxicity and human health impacts would have been overwhelming. The price of the NeemAzal was about 224% higher than actellic super. Because of the smaller quantity of harvest, smallholder farmers in Ghana do not enjoy huge rebates on prices of insecticides. Farmers also do not benefit from reduced treatment cost associated with economies of scale. The survey administered on maize farmers indicated that the number (%) of male farmers surpassed their female counterparts. Males cultivated larger acres of land compared to females, however, all the farmers are categorized as smallholder farmers. Farmers used conventional (traditional) methods during harvesting, drying, shelling, and storage. The conventional methods resulted in high losses in grain quality and quantity. PHL was due mainly to maize weevils or rodents attack, but not molds. Besides the usage of synthetic insecticides, some farmers also used plant materials like seeds or leaves from pepper, basil, and neem plants to control maize weevils. Farmers’ knowledge of molds and mycotoxin effects was generally good. But was very encouraging in NR, kudos to AEAs, as at least 93.0% of farmers had no formal education. In general, the physical disturbance method did not significantly cause S. zeamais mortality. Although the cause of the failure of the method cannot be pinpointed, it can be speculated to be due to human error or the large number of S. zeamais used inundated the disturbance technique, or the high temperature, RH and grain MC favored the growth and development of S. zeamais. Noteworthy, despite the failure of the physical disturbance in 266 causing S. zeamais mortality, the quality of grain in the disturbed buckets was maintained. The grain in the undisturbed was moldy, “caked”, and discolored. Grain was safely stored in hermetic GrainPro bags compared to woven polypropylene bags. S. zeamais mortality was 100.0% in GrainPro bags. None of the GrainPro bags was damaged but all the woven polypropylene bags were damaged by the S. zeamais. The profit margins and food security of farmers could improve as grain quantity and quality are maintained in GrainPro bags, and GrainPro bags are reusable. The efficacy of zeolite beads in this study reiterates its safe, fast, user-friendly, inexpensive, and adaptable method for drying maize and other cereal seeds without compromising seed germination and vigor. Seeds stored with zeolite beads did not require the use of refrigeration to maintain seed viability and vigor. This study also indicates that the formula used in calculating zeolite beads-to-seed ratio should be revised to prevent extreme desiccation which could be detrimental to seed quality. Farmers in Ghana and SSA are therefore recommended to use zeolite beads to dry or store seeds of even high MC as radiant energy is undependable and unpredictable. The annual capital and operational costs of handling maize grain with m. silo + acc. or m. silo were very high, and farmers could only afford the expenses by forming farmers- cooperatives. Contrarily, capital cost and operational cost of grain handling using PICS or w. PP. + Phos. or w. PP were essentially low and within the financial capabilities of individual smallholder farmers. Importantly, PICS had the lowest operational cost. Mechanized handling of grain (m. silo + acc.) should have been the best option since its capability to maintain grain quality and quantity is greatly doubtless, but due to financial constraints, farmers on an individual basis could adopt PICS bag (or similar types) instead 267 of w. PP. or w. PP. + Phos. Ghana's government can initiate the application of m. silo + acc. in grain handling to complement the success of the agricultural flagship programs. 10.2. Recommendations 1. The low oxygen concentration created in hermetic storage (jars or bags) of grains or seeds will kill S. zeamais. 2. Airtight jars containing seeds or grains stored at low temperatures (at most 30oC) will prevent grains or seeds moisture increase. 3. The manufacturing, transport, and usage of synthetic and botanical insecticides if curtailed will reduce CO2 emissions and impacts, human health and ecotoxicity impacts, and financial burdens on farmers. 4. Seeds hermetically stored with activated zeolite beads will prevent or minimize seed deterioration due to lipid peroxidation. 5. Mechanical handling (threshing to storage) of grain through the efforts of farmers- cooperatives will reduce post-harvest losses. 10.3. Future Work 1. The physical disturbance technique should be repeated in Ghana or any other West African nation with at most 12% maize grain moisture. 2. There should be a computer model incorporating MC, number of insects, temperature and RH, and time or cycles of shaking to establish a precise relationship between insect mortality and the periodic physical disturbance technique. 3. It would be imperative to apply physical disturbance method mechanically but not manually to eliminate any unforeseen human errors. 4. Further studies on the application of zeolite beads are essential to avoid extreme desiccation or under drying of seeds that affects seed viability and vigor.