DOCSLIB.ORG

Pages 406 To

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Pages 406 To 397 SOIL SALINITY CONTROL UNDER BARLEY CULTIVATION USING A LABORATORY DRY DRAINAGE MODEL Shahab Ansari 1,*, Behrouz Mostafazadeh-Fard 2, Jahangir Abedi Koupai3 Abstract The drainage of agricultural fields is carried out in order to control soil salinity and the water table. Conventional drainage methods such as lateral drainage and interceptor drains have been used for many years. These methods increase agriculture production; but they are expensive and often cause environmental contaminations. One of the inexpensive and more environmental friendly methods that can be used in arid and semi-arid regions to remove excess salts from irrigated lands to non- irrigated or fallow lands is dry drainage. In the dry drainage method, natural soil system and the evaporation of fallow land is used to control soil salinity and the water table of irrigated land. There are few studies about dry drainage concepts. it is also important to study soil salt changes over time because of salt movements from irrigated areas to non-irrigated areas especially under plant cultivation. In this study a laboratory model which is able to simulate dry drainage was used to investigate soil salts transport under barley cultivation. The model was studied during the barley growing season and for a constant water table. During the growing season soil salinities of irrigated and non-irrigated areas were measured at different time. The Results showed that dry drainage can control the soil salinity of an irrigated area. The excess salts leached from an irrigated area and accumulated in the non-irrigated area and the leaching rate changed over time. Soil surface salinities of non-irrigated areas increased with time. At the end of the experiment, the increase of the mean soil salinity of the non-irrigated area was 2.81 times more than the increase of the mean soil salinity of the irrigated area. In arid and semi-arid regions where suitable conditions exist, dry drainage can be used as a useful management tool to control soil salinity. KEY WORDS: Barley, Dry drainage, Salt movement, Shallow ground water. 1 Ph. D. Student, Water Engineering Department, College of Agriculture, Isfahan University of Technology, Isfahan, Iran. *Corresponding author: [email protected]; Isfahan University of Technology, Isfahan 84156-83111, Iran Tel: +989139780991. 2 Professor, Water Engineering Department, College of Agriculture, Isfahan University of Technology, Isfahan, Iran. Isfahan University of Technology, Isfahan 84156-83111, Iran. [email protected], Tel: +983133913430. 3 Professor, Water Engineering Department, College of Agriculture, Isfahan University of Technology, Isfahan, Iran. Isfahan University of Technology, Isfahan 84156-83111, Iran. [email protected], Tel: +983133913433. 398 Introduction During the last 3-4 decades, as the demand for agricultural productions increased the irrigated lands also increased up to 300%. This has imposed a further increase in soil salinization and a relative decrease in crop yield (Poustini and Siosemardeh, 2004). In arid and semi-arid regions, farmers often use saline water to irrigate their fields because of shortage of good quality water resources. This causes soil and water contaminations and reduces agricultural productions. Drainage is a common method to reduce salt accumulation in soil especially when irrigating with saline water. Salt leaching is one of the most important aims of the drainage systems, but it causes fertilities and pesticides to be removed from soil profile and pollute surface water and ground water resources (Deng, 1998). In recent years, researchers have tried to find more suitable and environmental acceptable method for drainage of agricultural fields. For example subsurface irrigation and controlled drainage are irrigation methods which can reduce pollution and still provide sufficient irrigation requirement (Ragab, 2002; Skaggs, 1999). Results of different researches have shown that it is beneficial if crop rotation is considered for land reclamation programs to decrease soil salinity. The subsurface drainage systems in agricultural fields are expensive and cause environmental pollutions. Dry drainage is a new concept for drainage of agricultural fields which has less environmental impacts and with low cost as compared to subsurface drainage systems can reduce soil salts and leach excess salts (Konukcu and et al., 2006). Greenwood et al. (1994) first have introduced dry drainage. In this method part of the field is considered as irrigated area and another part is considered as non-irrigated area or fallow land. Drainage occurred through soil of irrigated area and salts will leach to the non-irrigated area or fallow land. The gradients from irrigated area to non-irrigated area cause salts and excess water movements (Khouri, 1998). Dry drainage is efficient and applicable for conditions of high water table, high capillary rise and high potential of evaporation. These conditions are visible in many arid and semi-arid regions that suffer from salinity problems (Khouri, 1998). Konukcu, et al. (2006) reported that dry drainage is a sustainable solution to water logging and salinity problems in irrigated area. There are few researches about dry drainage and its practical use (JingWei and et al., 2009; Khouri, 1998). Previous studies had confirmed that dry drainage is more economical and environmental acceptable drainage method for agricultural fields. Therefore, the objective of this study was to simulate soil salinity under dry drainage with barley cultivation using a laboratory model. Materials and methods In this study a laboratory dry drainage simulation model was used to investigate soil salinity control under barley cultivation at Isfahan University of Technology, Isfahan, Iran. The model was made from galvanized sheet with thickness of 4 mm and with dimensions of 2 m length, 0.5 m width and 1 m height as shown in Fig.1. 399 0.5 m 1 m 0.5 m 0.5 m Fallow Irrigated Fallow area area area Soil surface 1 m Soil sluice Piezometer Soil sample collection 2 m Figure 1. The schematic of the laboratory dry drainage simulation model To observe water flow and ground water level in the model, one side of the model was made of the Plexiglas with thickness of 8 mm. Another side of the model had a grid system with vertical distance of 0.2 m and horizontal distance of 0.1 m. Half of these grid points were connected to polyethylene piezometers with inside diameter of 5 mm to measure and monitor groundwater level and other half were used to collect soil samples for soil moisture and soil salinity measurements. To drain water and to obtain desire water table, a drainage valve was installed at the bottom of the model. To obtain uniform water table, sand filter was placed at the bottom of the model. A water level controller connected to the drainage valve at the bottom of the model. It was able to raise water from the bottom to the top smoothly until it reaches the desire water level which was 0.6 m from the soil surface. The soil used for the study was loamy which was taken from an agricultural field. The physical and chemical characteristics of the soil are given in Table 1. The model was filled layer by layer by the soil and each layer was compacted uniformly to reach the bulk density which is close to bulk density of actual field. Model was divided into two equal sections of irrigated and non-irrigated (fallow) areas in such a way that due to hydraulic gradient changes, soil water and salt movements occur naturally between these two sections. The irrigated area was cultivated by barley and was irrigated with irrigation water which its characteristics are shown in Table 2. Irrigation water salinity was obtained by mixing good quality irrigation water with the saline water. The maximum irrigation interval was 3 days and irrigation amount changed with time. With irrigation, soil moisture was raised to field capacity and water table was raised to 0.6 m depth below soil surface. The experiment was carried out for one complete growth season of the barley 400 and mass soil water and salinity of irrigated area and non-irrigated area were measured at five different times of 0, 21, 42, 63 and 84 days after planting using soil samples taken at different locations of the model. Table 1. The characteristics of soil Sand Silt Clay Bulk density EC Characteristics pH (%) (gr/m3) (dS/m) value 52 28 20 1.6 3 8 Table 2. The characteristics of irrigation water Na+ Ca2+ Mg2+ K+ EC Characteristics pH (meq/L) (dS/m) value 5.99 9.15 8.14 2.94 3 7.5 Results and discussion Fig. 2 shows soil surface moistures of irrigated and non-irrigated areas for 0, 21, 42, 63 and 84 days after planting. Soil moistures of irrigated area and non-irrigated areas were equal at the beginning of the experiment. After plant cultivation, for first few weeks the difference between soil surface moistures increased due to irrigations. The differences decreased because of water movements from irrigated area to the non-irrigated area. Water movements occurred due to hydraulic gradient between two areas. Irrigations of irrigated area and also evaporation of soil surface of non-irrigated area increased the hydraulic gradient and caused water movements from irrigated area to non-irrigated area. Figure 2. Soil surface moistures for different times after planting Fig. 3 shows soil moistures at different depths for 84 days after planting for irrigated and non- irrigated areas. Soil moistures in both areas increased by soil depth due to capillary rise from water 401 table. Soil moisture at each depth for the irrigated area was more than the non-irrigated area. The difference of soil moisture at each depth of irrigated and non-irrigated areas increased as soil depth decreased due to irrigation of irrigated area and evaporation of non-irrigated area.
Load more

Recommended publications
  • Land Use Change, Modelling of Soil Salinity And
    KWAME NKRUMAH UNIVERSITY OF SCIENCE AND TECHNOLOGY, KUMASI, GHANA LAND USE CHANGE, MODELLING OF SOIL SALINITY AND HOUSEHOLDS’ DECISIONS UNDER CLIMATE CHANGE SCENARIOS IN THE COASTAL AGRICULTURAL AREA OF SENEGAL BY Sophie THIAM (BSc. Natural Sciences, MSc. Natural Resources Management and Sustainable Development) A Thesis submitted to the Department of Civil Engineering, College of Engineering in partial fulfilment of the requirements for the degree of DOCTOR OF PHILOSOPHY in Climate Change and Land Use June, 2019 DECLARATION I hereby declare that this submission is my own work towards the PhD in Climate Change and Land Use and that, to the best of my knowledge, it contains no material previously published by another person, nor material which has been accepted for the award of any other degree of the University, except where due acknowledgment has been made in the text. Sophie Thiam (PG7281816) Signature…………………Date………………... Certified by: Prof. Nicholas Kyei-Baffour Signature…………….…….Date……………… Department of Agricultural and Biosystems Engineering Kwame Nkrumah University of Science and Technology (Supervisor) Dr. François Matty Signature................................Date………… Institut des Sciences De l’Environnement University Cheikh Anta Diop of Dakar (Supervisor) Dr. Grace B.Villamor Signature………………….Date…………… Centre for Resilience Communities University of Idaho (Supervisor) Prof. Samuel Nii Odai Signature………………..Date………………. Head of Department of Civil Engineering i ABSTRACT Soil salinity remains one of the most severe environmental problems in the coastal agricultural areas in Senegal. It reduces crop yields thereby endangering smallholder farmers’ livelihood. To support effective land management, especially in coastal areas where impacts of climate change have induced soil salinity and food insecurity, this study investigated the patterns and impacts of soil salinity in a coastal agricultural landscape by developing an Agent-Based Model (ABM) for Djilor District, Fatick Region, Senegal.
    [Show full text]
  • Salinity Management and Soil Amendments for Southwestern Pecan Orchards J.L
    ARIZONA COOPERATIVE E TENSION College of Agriculture and Life Sciences AZ1411 Revised 10/11 SALINITY MANAGEMENT AND SOIL AMENDMENTS FOR SOUTHWESTERN PECAN ORCHARDS J.L. Walworth Introduction Managing salts in Southwestern pecan orchards can be a major 1.0 challenge for growers, due to limited soil permeability and/or 1219721972 low-quality irrigation water. However, effective, long-term salt 1319631963 management is essential for maintaining productivity of pecan 0.8 1219721972 orchards. The challenge is to effectively manage soil salinity and sodium (Na) in a cost-effective manner, using appropriate combinations of irrigation management, soil management, and 0.6 soil amendments. Formation of Soil Salinity 0.4 Many arid region soils naturally contain high concentrations of soluble salts, because soil weathering processes dependent 0.2 upon precipitation have not been sufficiently intense to leach RTD = -0.095 x ECe –1.09 salts out of soils. Irrigation water and fertilizers contain salts R = -0.89** that may contribute further to the problem. Poor soil drainage due to the presence of compacted layers (hardpans, plowpans, 0.0 caliche, and clay lenses), heavy clay texture, or sodium problems 0022446688 may prevent downward movement of water and salts, making implementation of soil salinity control measures difficult. ECe (dS/m) Adequate soil drainage, needed to allow leaching of water and salts below the root zone of the trees, is absolutely essential for Figure 1. Reduction in pecan relative trunk diameter with increasing soil effective management of soil salinity. salt concentrations. After Miyamoto, et al., Irrig. Sci. (1986) 7:83-95. The risk of soil salinity formation is always greater in fine- textured (heavy) soils than in coarse-textured soils.
    [Show full text]
  • Problems of Salination of Land in Coastal Areas of India and Suitable Protection Measures
    Government of India Ministry of Water Resources, River Development & Ganga Rejuvenation A report on Problems of Salination of Land in Coastal Areas of India and Suitable Protection Measures Hydrological Studies Organization Central Water Commission New Delhi July, 2017 'qffif ~ "1~~ cg'il'( ~ \jf"(>f 3mft1T Narendra Kumar \jf"(>f -«mur~' ;:rcft fctq;m 3tR 1'j1n WefOT q?II cl<l 3re2iM q;a:m ~0 315 ('G),~ '1cA ~ ~ tf~q, 1{ffit tf'(Chl '( 3TR. cfi. ~. ~ ~-110066 Chairman Government of India Central Water Commission & Ex-Officio Secretary to the Govt. of India Ministry of Water Resources, River Development and Ganga Rejuvenation Room No. 315 (S), Sewa Bhawan R. K. Puram, New Delhi-110066 FOREWORD Salinity is a significant challenge and poses risks to sustainable development of Coastal regions of India. If left unmanaged, salinity has serious implications for water quality, biodiversity, agricultural productivity, supply of water for critical human needs and industry and the longevity of infrastructure. The Coastal Salinity has become a persistent problem due to ingress of the sea water inland. This is the most significant environmental and economical challenge and needs immediate attention. The coastal areas are more susceptible as these are pockets of development in the country. Most of the trade happens in the coastal areas which lead to extensive migration in the coastal areas. This led to the depletion of the coastal fresh water resources. Digging more and more deeper wells has led to the ingress of sea water into the fresh water aquifers turning them saline. The rainfall patterns, water resources, geology/hydro-geology vary from region to region along the coastal belt.
    [Show full text]
  • Drainage Water Management R
    doi:10.2489/jswc.67.6.167A RESEARCH INTRODUCTION Drainage water management R. Wayne Skaggs, Norman R. Fausey, and Robert O. Evans his article introduces a series of the most productive in the world. Drainage needed. Drainage water management, or papers that report results of field ditches or subsurface drains (tile or plastic controlled drainage, emerged as an effec- T studies to determine the effec- drain tubing) are used to remove excess tive practice for reducing losses of N in tiveness of drainage water management water and lower water tables, improve traf- drainage waters in the 1970s and 1980s. (DWM) on conserving drainage water ficability so that field operations can be The practice is inherently based on the and reducing losses of nitrogen (N) to sur- done in a timely manner, prevent water fact that the same drainage intensity is face waters. The series is focused on the logging, and increase yields. Drainage is not required all the time. It is possible to performance of the DWM (also called also needed to manage soil salinity in irri- dramatically reduce drainage rates during controlled drainage [CD]) practice in the gated arid and semiarid croplands. some parts of the year, such as the winter US Midwest, where N leached from mil- Drainage has been used to enhance crop months, without negatively affecting crop lions of acres of cropland contributes to production since the time of the Roman production. Drainage water management surface water quality problems on both Empire, and probably earlier (Luthin may also be used after the crop is planted local and national scales.
    [Show full text]
  • Design & Development of Automatic Soil Salinity Control System
    International Journal of Latest Trends in Engineering and Technology (IJLTET) Design & Development of Automatic Soil Salinity Control System Praveen Kumar Department of Electronics and Communication Engineering MVN University, Palwal, Haryana, India Dr. S. K. Luthra Vice Chancellor MVN University, Palwal, Haryana India Dr. Rajeev Ratan Head of Department of Electronics and Communication Engineering MVN University, Palwal, Haryana India Abstract - The main objective of this project is to control soil salinity and improve soil fertility. The word salinity defines amount of salt present in water or soil which tends to decrease soil fertility through natural or human induced processes that results in the accumulation of dissolved salt in the soil water to an extent that inhibits plant growth and salinity is a severe environmental hazards that degrades the growth of many crops Spatial characterization of soil salinity is required for establishing salt control measurements in irrigated agriculture. For that, cost-effective, specific, rapid, and reliable methodologies for determining soil salinity in-situ and processing those data are required. Keywords: Microcontroller AT89S52, Soil Salinity, Salinity Sensor, salinity control I. INTRODUCTION Salinity means amount of salt in water and soil . soil salinity means unwanted amount of salt present in soil .As population is increasing so demands of food increasing ,soil salinity degrads quality of food availability in market. The accumulated salts include sodium , potassium, magnesium, calcium, chloride, sulphate, carbonate and bicarbonate. primary salinization involves salt accumulation through natural process due to high salt containment in ground water , whereas in secondary salinization is due to human interventions such as inappropriate irrigation procedure e.g with salt rich irrigation water.
    [Show full text]
  • Evaluation of Subsurface Drainage Techniques Used for Dryland Salinity
    EVALUATION OF SUBSURFACE DRAINAGE TECHNIQUES USED FOR DRYLAND SALINITY CONTROL A Thesis Submitted to the College of Graduate Studies and Research in Partial Fulfillment ofthe Requirements for the Degree ofMaster ofScience in the Division ofEnvironmental Engineering University ofSaskatchewan Saskatoon By Warren Douglas Helgason Fall 2000 © Copyright Warren Douglas Helgason, 2000. All rights reserved. PERMISSION TO USE In presenting this thesis in partial fulfillment ofthe requirements for a Postgraduate degree from the University ofSaskatchewan, I agree that the Libraries of this University may make it freely available for inspection. I further agree permission for copYing ofthis thesis in any manner, in whole or in part, for scholarly purposes may be granted by the professor or professors who supervised my thesis work or, in their absence, by the Head ofthe Department or the Dean ofthe College in which my thesis work was done. It is understood that any coPYing or publication or use ofthis thesis or parts thereoffor financial gain shall not be allowed without my written permission. It is also understood that due recognition shall be given to me and to the University of Saskatchewan in any scholarly use which be made ofany material in my thesis. Requests for permission to copy or to make other use ofmaterial in this thesis in whole or in part should be addressed to: Chair ofthe Division ofEnvironmental Engineering University ofSaskatchewan Saskatoon, Saskatchewan, sm 5A9 1 DATA ACKNOWLEDGEMENTS AND RESTRICTIONS All raw data used in this study dated prior to 1997 were collected by the staffat Agriculture and Agri-Food Canada's Semiarid Prairie Agricultural Research Centre (SPARC) in Swift Current, Saskatchewan.
    [Show full text]
  • Concentrated Alkaline Recharge Pools for Acid Seep Abatement: Principles, Design,Construction and Performance1
    CONCENTRATED ALKALINE RECHARGE POOLS FOR ACID SEEP ABATEMENT: PRINCIPLES, DESIGN,CONSTRUCTION AND PERFORMANCE1 Jack R. Nawrot', Pat S. Conley2, and James E. Sandusky' Abstract: Concentrated alkaline recharge pools have been constructed above previously soil covered acid gob at the Peabody Will Scarlet Mine to abate acid seeps. Preliminary monitoring results (1989-1994) from a concentrated alkaline recharge pool demonstration project in the Pit 4 area have documented a 45 to 90 % reduction in acidity in the principal recharge pool groundwater zone. A 23 % reduction in acidity has occurred in the primary seep located downslope from the alkaline recharge pools. The initial improvements in water quality are seen as a positive indication that groundwater acidity will decrease further and amelioration of the acid seep will continue. Additional Key Words: acid seeps, mine refuse, acid mine drainage, alkaline recharge. Introduction Covering acid producing coal refuse with 4-ft of soil cover does not preclude pyrite oxidation under the soil cover. When pyrite oxidation does occur overlying soil covers may become acidified and acid seeps may be generated following several seasons of rainfall infiltration and flushing cycles. Burial of potentially acid producing coal waste in a zone of fluctuating groundwater elevations is conducive to chronic acid seep generation when. the upslope groundwater chemistry has insufficient alkalinity to neutralize downslope acid groundwater pools generated by the buried refuse. Soil covering after limestone is applied in sufficient quantities to overcome the potential acidity · of refuse, or limestone amendment and direct seeding are effective reclamation techniques that enhance long-term vegetation success and establish a favorable acid-base balance (Warburton et al.
    [Show full text]
  • Information Sources on Land Drainage
    - Educational Low-Priced Books Scheme, British Council: Book Coupons Programme; and British Council: Resale Scheme. Contact your local British Council representative; - Head, Information and Documentation, Swedish Agency for Research Cooperation with Developing Countries; - Third World Academy of Science, Donation Programme; - CTA. 26.4 Information Sources on Land Drainage 26.4.1 Tertiary Literature Tertiary literature gives information on abstract journals, journals, addresses of institutions, dictionaries, etc. It may have titles such as Sources of Information on .... An example is: Naber, G. Drainage : An Annotated Guide to Books and Journals Wageningen, ILRI, 1984.37 p. Gives an overview of sources of information, abstract journals, journals, bibliographies, directories, dictionaries, and books. Several titles are illustrated by their front cover. 26.4.2 Abstract Journals Abstract journals list titles of publications with an abstract of their contents. Examples are: - Soils and Fertilizers Published twelve times a year by CABI. Subscription price U.S. $680/year. - Irrigation and Drainage Abstracts Published five times a year by CABI. Subscription price U.S. $160/year. - Bibliography of Irrigation, Drainage and Flood Control Published once a year by the International Commission on Irrigation and Drainage/ICID, India. 26.4.3 Databases The book Online Databases in the Medical and Life Sciences, published by Elsevier, lists various interesting databases and their products. The following databases cover the field of tropical agriculture. Although not entirely concerned with land drainage, they will be of interest to land drainage engineers. They are also available on compact disc: - AGRICOLA, produced by the U.S. Department of Agriculture, National Agricultural Library; 1072 - AGRIS, International Information System for the Agricultural Sciences and Technology, produced by AGRIS Coordinating Centre, FAO; - CAB Abstracts, produced by CAB International, available online in DIALOG, DIMDI, and ESA.
    [Show full text]
  • Salinity Management for Sustainable Irrigation Integratingscience, Environment, and Economics Public Disclosure Authorized Public Disclosure Authorized
    ENVIRONMENTALLY AND SOCIALLY SUSTAINABLE DEVELOPMENT 1~~U) Rural Development Work in progresS 20842 for public discussion August 2000 Public Disclosure Authorized Salinity Management for Sustainable Irrigation IntegratingScience, Environment, and Economics Public Disclosure Authorized Public Disclosure Authorized f~~~~~~~~~~~~~~~~~~~~~~~~~~i:2 Public Disclosure Authorized Daniel Hillel wit/ an appendix by E. Feinerman ENVIRONMENTALLY AND SOCIALLY SUSTAINABLE DEVELOPMENT Rural Development Salinity Management for Sustainable Irrigation IntegratingScience, Enzvronment, and Economics DanielHillel withan appendixby E. Feinerman The WorldBank Washington,D.C. Copyright (©2000 The International Bank for Reconstruction and Development/THE WORLD BANK 1818 H Street, N.W. Washington, D.C. 20433, U.S.A. All rights reserved Manufactured in the United States of America First printing August 2000 12340403020100 This report has been prepared by the staff of the World Bank. The judgments expressed do not necessarily reflect the views of the Board of Executive Directors or of the govermnents they represent. The World Bank does not guarantee the accuracy of the data included in this publication and accepts no responsibility for any consequence of their use. The boundaries, colors, denominations, and other in- formation shown on any map in this volume do not imply on the part of the World Bank Group any judg- ment on the legal status of any territory or the endorsement or acceptance of such boundaries. The material in this publication is copyrighted. The World Bank encourages dissemination of its work and will normally grant permission promptly. Permission to photocopy items for internal or personal use, for the internal or personal use of specific clients, or for educational classroom use, is granted by the World Bank, provided that the appropriate fee is paid directly to Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, U.S.A., telephone 978-750-8400, fax 978-750-4470.
    [Show full text]
  • Modeling Subsurface Drainage to Control Water-Tables in Selected Agricultural Lands in South Africa
    Institute of Water and Energy Sciences (Including Climate Change) MODELING SUBSURFACE DRAINAGE TO CONTROL WATER-TABLES IN SELECTED AGRICULTURAL LANDS IN SOUTH AFRICA Cuthbert Taguta Date: 05/09/2017 Master in Water, Policy track President: Prof. Masinde Wanyama Supervisor: Dr. Aidan Senzanje External Examiner: Dr. Kumar Navneet Internal Examiner: Prof. Sidi Mohammed Chabane Sari Academic Year: 2016-2017 Modeling Subsurface Drainage in South Africa Declaration DECLARATION I Taguta Cuthbert, hereby declare that this thesis represents my personal work, realized to the best of my knowledge. I also declare that all information, material and results from other works presented here, have been fully cited and referenced in accordance with the academic rules and ethics. Signature: Student: Date: 05 September 2017 i Modeling Subsurface Drainage in South Africa Dedication DEDICATION To the Taguta Family, Where Would I be Without You? Continue to Shine! My son Tawananyasha and new daughter Shalom, may you grow to heights greater than mine! ii Modeling Subsurface Drainage in South Africa Abstract ABSTRACT Like many other arid parts of the world, South Africa is experiencing irrigation-induced drainage problems in the form of waterlogging and soil salinization, like other agricultural parts of the world. Poor drainage in the plant root zone results in reduced land productivity, stunted plant growth and reduced yields. Consequentially, this hinders production of essential food and fiber. Meanwhile, conventional approaches to design of subsurface drainage systems involves costly and time-consuming in-situ physical monitoring and iterative optimization. Although drainage simulation models have indicated potential applicability after numerous studies around the world, little work has been done on testing reliability of such models in designing subsurface drainage systems in South Africa’s agricultural lands.
    [Show full text]
  • Assessing US Farm Drainage
    Assessing U.S. Farm Drainage: WORLD Can GIS Lead to Better Estimates of Subsurface RESOURCES Drainage Extent? INSTITUTE ZACHARY SUGG SUMMary Extensive agricultural subsurface tile drainage in the Midwestern U.S. has important implications for nutrient pollution in surface water, notably the “dead zone” in the Gulf of Mexico. However, drainage data limitations have constrained efforts to effectively factor tile drainage into regional economic and environmental impact studies. Improved drainage data would be a valuable addition to future modeling applications. In light of this need, a methodology incorporating a geographic information system (GIS) analysis based on soil and land cover maps was implemented to create a set of county-level tile drainage extent estimates. • For several leading agricultural drainage states, maps of soil drainage characteristics were created and overlaid with row crops. Areas with row crops and poorly drained soils were calculated, disaggregated to the county level, and reduced by a percentage based on published estimates to approximate subsurface drainage. Results for eight highly-drained Midwest states were compared to previous estimates. A range of tile drainage estimates were compiled, along with a final best-guess county- level database of tile drained area. • This represents just one set of methods, and without sufficient data for verification it may be difficult to judge its effectiveness compared to others. By demonstrating one method, we hope to encourage further exploration of the use of GIS for predicting and assessing farm drainage. More importantly, we aim to further the dialogue regarding the relationship between drainage and water quality in the U.S. and highlight the need for improved measurement of this key agricultural practice.
    [Show full text]
  • Risk Assessment of Soil Salinization Due to Tomato Cultivation in Mediterranean Climate Conditions
    water Article Risk Assessment of Soil Salinization Due to Tomato Cultivation in Mediterranean Climate Conditions Angela Libutti * , Anna Rita Bernadette Cammerino and Massimo Monteleone Department of Science of Agriculture, Food and Environment, University of Foggia, 71122 Foggia, Italy; [email protected] (A.R.B.C.); [email protected] (M.M.) * Correspondence: [email protected]; Tel.: +39-0881-589128 Received: 11 September 2018; Accepted: 20 October 2018; Published: 23 October 2018 Abstract: The Mediterranean climate is marked by arid climate conditions in summer; therefore, crop irrigation is crucial to sustain plant growth and productivity in this season. If groundwater is utilized for irrigation, an impressive water pumping system is needed to satisfy crop water requirements at catchment scale. Consequently, irrigation water quality gets worse, specifically considering groundwater salinization near the coastal areas due to seawater intrusion, as well as triggering soil salinization. With reference to an agricultural coastal area in the Mediterranean basin (southern Italy), close to the Adriatic Sea, an assessment of soil salinization risk due to processing tomato cultivation was carried out. A simulation model was first arranged, then validated, and finally applied to perform a water and salt balance along a representative soil profile on a daily basis. In this regard, long-term weather data and physical soil characteristics of the considered area (both taken from international databases) were utilized in applying the model, as well as considering three salinity levels of irrigation water. Based on the climatic analysis performed and the model outputs, the probability of soil salinity came out very high, such as to seriously threaten tomato yield.
    [Show full text]