Pepijn Schreinemachers (Autor) The (Ir)relevance of the Crop Yield Gap Concept to Food Security in Developing Countries

Transcription

1 Pepijn Schreinemachers (Autor) The (Ir)relevance of the Crop Yield Gap Concept to Food Security in Developing Countries Copyright: Cuvillier Verlag, Inhaberin Annette Jentzsch-Cuvillier, Nonnenstieg 8, Göttingen, Germany Telefon: +49 (0) , Website:

2 Table of contents (brief) Summary...ix Acknowledgements...xiii Abbreviations...xv 1 Introduction The (ir)relevance of crop yield gaps in developing countries Conceptual frame and analytical approach General methodology Generation of landscapes and agent populations Crop yield and soil property dynamics Production behavior Consumption behavior Simulation results Discussion References Appendix Table of authorities i

3 Table of contents (detailed) Summary...ix Acknowledgements...xiii Abbreviations...xv 1 Introduction Introduction Problem background The crop yield gap and food security The crop yield potential Need for integrated approaches Objectives Approach Main methodological contributions Main collaborations Outline of the thesis The (ir)relevance of crop yield gaps in developing countries Introduction The crop yield gap The yield gap concept Background The yield gap debate Misconceptions about crop yield gaps Farmers want a higher yield potential A higher yield potential is needed to meet future demands A higher yield potential increases food security A higher yield potential is needed to keep prices low More than genes The importance of creating an enabling environment The limited relevance of national average yields Summary ii

4 3 Conceptual frame and analytical approach Introduction Decomposing crop yield gaps Proximate factors Underlying factors Socioeconomic dimensions of the yield gap Private objectives Social objectives Application to Uganda Southeast Uganda Maize in Uganda Summary General methodology Introduction Methodological approach Heterogeneity Mathematical programming-based multi-agent systems (MP-MAS) Introduction of system components Farm agents Landscape Biophysics Heterogeneity, interaction, and dynamics Heterogeneity Interaction Dynamics Mixed integer linear programming (MILP) Non-separable farm decision-making Concise theoretical model A three-stage non-separable decision process Investments Production Consumption Software implementation Summary iii

5 5 Generation of landscapes and agent populations Introduction The landscape Data Sources The villages of Magada and Buyemba Landscape representation Location of agents and farm plots (layers 1-3) The socioeconomic landscape (layers 4-5) Soil chemical properties (layers 6-10) Soil physical properties (layers 11-12) The agents Data Sources Generating an agent population Random data generation Consistency checks Validation of results Population level Cluster level Agent level Summary Crop yield and soil property dynamics Introduction Background Problem background Theoretical background The Tropical Soil Productivity Calculator (TSPC) Four phases in soil property dynamics Phase 1: yield determinants Phase 2: crop yield Phase 3: soil property updating Phase 4: soil property balances Model calibration Crops included Crop physical characteristics Crop chemical characteristics Crop yield response functions Validation of results Summary iv

6 7 Production behavior Introduction Crop yield response to labor use Frontier production function Production data used Model estimates Labor response factor The diffusion of innovations Theoretical background Empirical application Agent yield expectations Theoretical background Empirical application Production of livestock, coffee, vegetables and fruits Livestock production Coffee production Fruit and vegetable production Further constraints and incentives to production Labor availability Labor time allocation Labor allocation by gender Rotational constraints Intercropping Crop pests and diseases Risk Input prices Validation of results Summary v

7 8 Consumption behavior Introduction A three-step budgeting process Theoretical background Theoretical model Savings and expenditures (Step 1) Food and non-food expenditures (Step 2) Almost Ideal Demand System (Step 3) Quantifying poverty from food energy needs and intake levels Coping strategies to food insecurity Fertility and mortality Data and estimation Budget data used Savings and expenditures (Step 1) Food and non-food expenditures (Step 2) Almost Ideal Demand System (Step 3) Market prices Food energy needs and intake levels Opportunity cost of farm labor and migration Population growth and HIV/Aids Validation of results Summary Simulation results Introduction The baseline scenario Defining the baseline scenario Sensitivity of the baseline to initial conditions Baseline dynamics: soil fertility decline and population growth The maize yield gap Decomposition in proximate factors The maize yield gap and farm performance The maize yield gap vs. economic well-being and food security Maize yield gap dynamics Decomposition in underlying factors The impact of crop breeding The effect of HIV/Aids Summary vi

8 10 Discussion Introduction Limitations of the study Low data quality Migration Sources of heterogeneity Unknown crop yield response functions Absence of local factor and output markets An ex-post comparison of approaches Recommendations for research References Appendix Table of authorities vii