Badee Bishaw Based on This Analysis, to Propose an Alternative
Total Page：16
File Type：pdf, Size：1020Kb
AN ABSTRACT OF THE THESIS OF Badee Bishaw for the degree of Doctor of Philosophy in Forest Resources presented on May 6. l993. Title: Determining Options for Aroforestry Systems forthe Rehabilitation of Degraded Wateisheds in Alemaya Basin. Hararghe Hi hiands. Ethiopia. Abstract approved: / rof. Robert E. Buckman Deforestation, accelerated soil erosion, and land degradation are serious problems in Ethiopia. The uncontrolled removal of natural forests, demographic pressures and cyclical drought has aggravated the situation, resulting in massive environmental degradation anda serious threat to sustainable agriculture and forestry. To overcome these problems efforts have been made to launch an afforestation and conservation program; however,success to date has been limited. Thus, the main objective of this study is to findthe reasons for lack of success in tree planting in the Alemaya Basin both from biophysical and socio-economicperspectives. And, based on thisanalysis, to propose an alternative strategy for agroforestry for the Basin. The study has identified and characterized major land uses, socio-economic constraints and agricultural and forestry practices which have limited forestry development in the Alemaya Basin. To gather the necessary information for the study, existing information sources were reviewed.Two stage sampling was used for a land-usesurvey, and stratified random sampling for the socio-economic study. Decrease in farm size due to population increases, soil erosion, shortage of fuelwood and fodder for livestock and lack of appropriate extension service were found to be the major problems that affect sustainable production in the Aleinaya Basin. Agroforestry is one of the appropriate technologies to overcome some of the problems faced by the farmers in the AlemayaBasin. Thestudy proposeda desired state of sustainable agriculture and forestry for the Basin basedon population projections, agriculture and forest products needs, and stable or improved living standards fora 20 year planning period. Alley cropping with and without fertilizers was identified asa promising agroforestry technology. Its economic feasibility was assessed by estimating costs and returns both for traditional farming and alley cropping. Determining Options for Agroforestry Systems for the Rehabilitation of Degraded Watersheds in Alemaya Basin, Hararghe Highlands, Ethiopia by Badege Bishaw A THESIS submitted to Oregon State University In partial fulfillment of the requirements for the degree of Doctor of Philosophy Completed Nay 6, 1993 Commencement June 1993 Pzlofessor of F'orest Resources in charge of major ad of department of Forest Resources Dean of Gradte Schoo Date thesis is presented May 6, 1993 Typed by Bezunesh Abebe for Badege Bishaw ACKNOWLEDGMENTS I would like to express my sincere appreciation tomy major Professor,Dr Robert E.Buckman for his guidance, encouragement, nd critical reading of the manuscript. His patience and expertise are greatfully acknowledged. My gratitude to Dr. J. Douglas Brodie of the Department of Forest Resources, Oregon State University, for providing valuable advice to the data analysisand constructive criticism throughout the preparation of this thesis. My sincere acknowledgement to my committee members: Dr. Steven Sharrow, Department of Rangeland Resources,and Dr. David Hibbs, Department of Forest Sciences, for their constructive comments on my manuscripts. My many thanks to the Ethiopian Government and the World Bank for sponsoring my study at the Oregon State University and funding the research project in Ethiopia.My gratitude to Mr. Ralph Hull for his generous financialsupport for the final part of the thesis preparation. My special thanks to Dr. David Acker, Associate Director, Office of International Research and Development,Oregon State Universityfor his continuoussupportand encouragement throughout my study in the U.S.A. I would also like to thank Dr. Mulugeta Semru, ex-Vice Minister of Higher Education and Dr. Dejene Makonnen ex-President of Alemaya University of Agriculture for their encouragement and providing facilities during the field survey. My thanks to the faculties of the Department of Forest Resources and College of Forestry for their financial support and professional inspiration. My gratitude to Dr. Bjorn O.Lundgren, ex-Director General of ICRAF for allowing me to visit ICRAF anduse the Library and other facilities of the center.The experts and staff of ICRAF are also acknowledged for sharing their experience and advice during my visit there. I thank my friends and associates for assistance, ideas, and support through the years ofmy study. I would also like to thank all the team members of the fieldsurvey, who helped me collecting the necessary data for this study. Finally, thanks to all my family for their encouragement; especially my wife Bezunesh Abebe, for typing the manuscript and her patience throughout my study. TABLE OF CONTENTS Page, INTRODUCTION 1 BIOPHYSICAL CHRACTERIBTICS OF ETHIOPIA AND THE ALEMAYA BASIN 6 21. Location 6 2.2. Topography 6 2.3. Climate 9 2.4. Geology and soils 12 2.5. Ecological zones and land use systems 14 THE ETHIOPIAN SETTING: A LITERATURE REVIEW 17 3.1. Land use and Natural vegetation 17 3.1.1. Land use 17 3.1.2. Forest and Forestry practice 19 3.1.2.1. Forest Resource of Ethiopia 19 3.1.2.2. Present Forestry Development 23 3.1.3. Crop production and soil erosion 28 3.1.4. Livestock and pasture resources 33 3.1.5. Agroforestry potential and practices 35 3.1.6. Relevant agroforestry experience and experiments 43 TABLE OF CONTENTS CONTINUED Page 3.2. Demographic, tenure, and socio-economic conditions 55 3.2.1. Population 55 3.2.2. Land and tree tenure 59 3.2.3. The economy 61 3.2.4. Socio-political conditions of Ethiopia 66 4. METHODSND PROCEDURES 69 4.1. Identification and source of information 69 4.2. Methods for land use survey 70 4.2.1. Planning the land use inventory 71 4.2.2. Sampling methods and procedures 74 4.2.3. Technological and operational options 75 4.2.4. Data processing and analysis 77 4.2.5. Technical and organizational problems 77 4.3. Method for socio-economic survey 78 4.3.1. Survey methods 80 4.3.2. Methods and procedures 82 4.3.3. Data processing and analysis 83 4.3.4. Organizational and management problems 84 TABLE OF CONTENTS CONTINUED Pacie RESULTS AND DISCUSSION 86 5.1. Results of the land use survey 86 5.2. Results of agriculture and forestry survey 90 5.2.1. Crop production subsystem 91 5.2.2. Livestock production subsystem 99 5.2.3. Tree production subsystem 103 5.3. Results of socio-economic survey 108 CHARACTERIZE A DESIRED STATE OP SUSTAINABLE AGRICULTURE AND FORESTRY FOR THE BASIN 124 6.1. Introduction 124 6.2. Projections of population 127 6.3. Projections of crop, livestock and tree production 130 6.4. Projections of living standards 147 RECOMMENDATIONS AND CONCLUSIONS 152 7.1. General summary 152 7.2. Technical recommendation 153 7.3. Recommendation for implementation 154 7.4. Socio-economic and institutional aspects 160 7.5. Dealing with uncertainty 164 7.6. Suggested area of research 166 TABLE OF CONTENTS CONTINUED Pace BIBLIOGRAPHY 169 APPENDICES 176 Appendix 1: Tally sheet for land-use, agroforestry and tree husbandary survey in the Aleinaya Basin Appendix 2: Formal survey questionnaire for household interview in the Alemaya Basin Appendix 3: Landscape niches, tree species and agroforestry practices identified in the Alemaya Basin 1990/91 Appendix 4: Summary results of logistic regression and log-linear analysis. Appendix 5: Cropping calendar by agricultural activity for the Alemaya Basin LIST OF FIGURES Figure Page Administrative Regions of Ethiopia 7 Topographic Map of Alemaya Basin 8 Mean Annual Rainfall Ethiopian Highlands 11 Major Agroecological zones Ethiopian Highlands 15 Forest Cover map of Ethiopia at the end of the 1970's 22 Severity of Soil Degradation due to soil Erosion in Ethiopia 32 Projection of income/person in ETBirr for 20 yearswith high yield assumption 148 LIST OF TABLES Table Page Major agro-ecological zones of the Ethiopian highlands 16 Land use and vegetation in Ethiopia 18 Present (1990) natural forest vegetation Coverage of Ethiopia 21 Estimated rates of soil loss on slopes in Ethiopia 30 Composition of livestock in highlands and lowlands of Ethiopia 33 Periodic fresh biomass, wood and foliage yields (tons/ha) of Leucaena leucocephala at Alemaya between 1988-1992 48 Seed yield and yield components of maize as influenced by leguminous tree species 49 Dry matter, crude protein, neutral detergent fiber, acid detergent fiber, lignin, ash, and ADF-ash of the browse legume trees 50 Grain yield (t/ha) of main season maize in Maize-cowpea rotation growth on a sandy soil in alley farming with Leucaena, adapted from Kang et. al.,(1990) 54 Classification for land-use (adapted with some modification from Anderson 1976) 71 Present land-use patter Alemaya Basin 1990/91 87 LIST OF TABLES CONTINUED Table Page Proportion of land-use types in the different slope classes in hectares in the Alemaya Basin 1990/91 88 Variance associated with major and minor land-uses in percent 90 Estimated average yields of the major crops in tons/hectare in the Alemaya Basin 1990/91 94 Crops yields in tons per hectare for major crops in Alemaya and Eastern Hararghe Highlands for periods between 1980's and 1990's 94 Farmers response to the problems of crop production in the Alemaya Basin 1990/91 98 Development of livestock per household in the Alemaya Basin 1980-1990/91 100 Farmers response to the problems of livestock