Introduction 1 1.2 Objectives 3 1.3 Organization of the thesis 4 CHAPTER 2-LITERATURE REVIEW 6 2.1 Introduction 6 2.2 Soil water as a resource in agriculture 6 2.3 Light as a resource in agriculture 12 2.4 Dry Zone as a production area 17 2.5 Alley cropping as a production system 21 CHAPTER 3-RESEARCH METHODOLOGY 31 3.