As the world population increases, there is increasing competition for waterquantity as well as quality. Provided here is an up-to-date perspective on Available Water Resources (Part I), Water Conservation and Technology inAgricultural Systems (Part II), Problem Water Uses and Treatment (Part III),and Management and Policy Evaluation (Part IV). The book is an invaluable source of information for water resource planners, managers and policy makers, researchers and students, and irrigationists.

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I Water Resources and Water Quality.- 1 Global Water Resources and Agricultural Use.- 1.1 Introduction.- 1.2 Global and Continental Water Resources.- 1.2.1 World Water Cycle and Budget.- 1.2.2 Continental Water Resources.- 1.2.3 Global Water Uses.- 1.3 Agricultural Uses of Water.- 1.3.1 United States Agricultural Water Uses.- 1.3.2 United States Irrigation Budget.- 1.3.3 Global Agricultural Water Uses.- 1.4 Anticipated Impacts on Future Agricultural Water Use.- 1.4.1 Competition for Water Quantity and Quality from Other Sectors.- 1.4.2 Increasing Regulation on Agricultural Waters.- 1.4.3 Ecological Impacts.- 1.5 Strategies for the Future.- 1.5.1 New Water Supplies.- 1.5.2 Water Conservation.- 1.5.3 Better Use of Rainwater.- 1.5.4 Institutional and Policy Changes.- 1.6 Summary and Conclusions.- References.- 2 Water Suitability for Agriculture.- 2.1 Introduction.- 2.2 Water Quality - Origin Dependence.- 2.2.1 Natural Origin.- 2.2.2 Man's Activities as the Origin.- 2.3 Quality Parameters Relevant to Crop Production.- 2.3.1 Salinity.- 2.3.2 Acidity-Alkalinity.- 2.3.3 Specific Ion Effect.- 2.3.4 The Effect of Micropollutants.- 2.4 Quality Parameters Relevant to Animal Production.- 2.4.1 Chemical Parameters.- 2.4.2 Biological Parameters.- 2.5 Water Quality - Soil Quality Relationship.- 2.5.1 Soils.- 2.5.1.1 Salts.- 2.5.1.2 Trace Elements.- 2.5.1.3 Organic Micropollutants.- 2.5.2 Soil Hydraulic Properties.- 2.5.2.1 Salinity - Alkalinity Effect.- 2.5.2.2 Effects of Suspended Particles.- 2.5.3 Soil Microflora.- References.- II Water Conservation and Technology.- 3 Crop Irrigation.- 3.1 Crop Water Status and Its Components.- 3.2 Evapotranspiration and Crop Water Requirement.- 3.2.1 Direct Methods.- 3.2.2 Indirect Methods.- 3.3 Irrigation Timing.- 3.3.1 Soil Moisture Content.- 3.3.2 Soil Water Tension.- 3.3.3 Evapotranspiration Rate.- 3.3.4 Plant Parameters.- 3.4 Implication of Irrigation Method on Scheduling.- 3.4.1 Surface Irrigation.- 3.4.2 Sprinkler Irrigation.- 3.4.3 Trickle and Drip Irrigation.- 3.5 Effect of Crop Growth Stage on Irrigation Practices.- 3.5.1 Vegetative Growth.- 3.5.2 Flowering.- 3.5.3 Fruit Development.- 3.5.4 Irrigation at Different Growth Stages Under Limited Irrigation Water.- 3.6 Irrigation Management in Humid Areas.- References.- 4 Irrigation Techniques and Evaluations.- 4.1 Introduction.- 4.1.1 Farm Irrigation Methods.- 4.1.2 Definitions of Efficiency and Uniformity.- 4.1.3 Project or River Basin Considerations.- 4.2 Surface Irrigation.- 4.2.1 Classification of Types.- 4.2.2 Conditions of Applicability.- 4.2.3 Practices.- 4.2.4 Constraints to Adoption.- 4.2.4.1 Constraint to Efficient Use of Water.- 4.2.5 Evaluation Methods.- 4.3 Sprinkler Irrigation.- 4.3.1 Classification of Types.- 4.3.1.1 Fixed Sprinklers.- 4.3.1.2 Continuous-Move Sprinklers.- 4.3.1.3 Types of Sprinkler Outlets and Nozzles.- 4.3.2 Conditions of Applicability.- 4.3.3 Practices.- 4.3.4 Constraints to Adoption.- 4.3.4.1 Constraints to Efficient Use of Water.- 4.3.5 Evaluation Methods.- 4.4 Micro-irrigation.- 4.4.1 Classification of Types.- 4.4.2 Conditions of Applicability.- 4.4.3 Practices.- 4.4.4 Constraints to Adoption.- 4.4.4.1 Constraints to Efficient Use of Water.- 4.4.5 Evaluation Methods.- 4.5 Considerations in Irrigation Method Selection.- References.- 5 Drainage and Subsurface Water Management.- 5.1 Introduction.- 5.2 Drainage Requirements.- 5.2.1 Trafficability.- 5.2.2 Protection from Excessive Soil Water Conditions.- 5.2.3 Salinity Control.- 5.2.4 Limiting Factors and Constraints.- 5.3 Subirrigation.- 5.4 Design and Analysis of Drainage Systems.- 5.4.1 Drainage Methods.- 5.4.2 Drainage Theory and Simulation Models.- 5.5 Simulation Analyses.- 5.5.1 Drainage.- 5.5.2 Subirrigation.- 5.6 Economic Analyses.- 5.7 Off-Site Impacts.- References.- 6 Runoff Irrigation.- 6.1 Introduction.- 6.2 Present Development and Expansion of Runoff Irrigation.- 6.3 Generation of Runoff.- 6.3.1 General Principles.- 6.3.2 Rainfall Simulators.- 6.3.3 Runoff as a Result of Crust Formation.- 6.3.4 Physical Models of Runoff Formation in Crusting Soils.- 6.4 Modeling Watershed Runoff Production.- 6.4.1 Microcatchment Water Harvesting.- 6.4.2 Modeling Rainfall Runoff Relationships for an SCWH Element.- 6.4.3 The Role of PAC in Water Harvesting.- 6.5 Runoff Irrigation and Remote Sensing.- 6.6 Agricultural Use of Runoff Water.- 6.6.1 Engineering Description of Water Harvesting Systems.- 6.6.1.1 Microcatchment Water Harvesting.- 6.6.1.2 Small Catchment Water Harvesting.- 6.6.1.3 Comparison of MCWH and SCWH Systems.- 6.6.2 Agroforestry.- 6.7 Concluding Remarks.- References.- 7 Efficient Use of Water in Rain-Fed Agriculture.- 7.1 Introduction.- 7.1.1 Definitions.- 7.1.1.1 Rain-Fed vs. Dryland Agriculture.- 7.1.1.2 Water Use Efficiency.- 7.1.2 Objectives of Dryland Farming.- 7.1.2.1 Subsistence Farmers.- 7.1.2.2 Farmers in a Market Economy.- 7.1.2.3 National Economy (Institutional Interest).- 7.1.3 The Relation Between Yield Production Objectives and Water Supply to Crops.- 7.1.3.1 The Yield Response Curve.- 7.1.3.2 Water Use Efficiency vs. Water Use.- 7.1.3.3 Yield vs. Water Use Efficiency.- 7.1.3.4 The Effects of Increasing or Decreasing Consumptive Use (CU).- 7.1.4. Constraints to Efficient Water Use.- 7.1.4.1 Climatic Constraints.- 7.1.4.2 Soil Physical Properties.- 7.1.4.3 Soil Salinity.- 7.1.4.4 Fertility and Nutrient Availability.- 7.1.4.5 Weeds.- 7.1.4.6 Pests and Diseases.- 7.2 Options for Improving Water Use Efficiency.- 7.2.1 Increase the Nominator of the Water Use Efficiency.- 7.2.2 Decrease Denominator of Water Use Efficiency - Water Conservation.- 7.2.2.1 Eliminate Runoff Losses.- 7.2.2.2 Decreasing Evaporation Losses.- 7.2.2.3 Limiting Deep Drainage.- 7.2.2.4 Use of Anti-Transpirants.- 7.3 Integrated Strategies for Efficient Water Use - Farming Systems.- 7.3.1 Conservation Tillage.- 7.3.1.1 Contour Cultivation and Strip Cropping.- 7.3.1.2 Modifying Soil Surface Micro-Relief to Increase Retention.- 7.3.1.3 Various Unconventional Tillage Principles and Implements.- 7.3.1.4 Major Land Shaping for Runoff Control.- 7.3.1.5 Residue Management.- 7.3.2 Crop Rotations Including Fallow Periods.- 7.3.3 Conjunctive Use of Rainfall and Irrigation.- 7.3.4 Runoff Farming.- 7.4 Concluding Remarks.- References.- III Problem Water Uses and Treatment.- 8 Irrigation with Saline Water.- 8.1 Introduction.- 8.2 Potential for Using Saline Water for Irrigation.- 8.2.1 Historical Evidence.- 8.2.2 Limitations and Potential Long-Term Effects.- 8.3 Factors that Facilitate the Use of Saline Water.- 8.3.1 Irrigation Water Sources.- 8.3.2 Site Considerations.- 8.3.3 Crop Selection.- 8.4 Management of Saline Water to Optimize Crop Performance.- 8.4.1 Crop Salt-Tolerance Expressions.- 8.4.2 Utilizing a Single Source of Water.- 8.4.3 Utilizing Waters From Multiple Sources of Variable Quality.- 8.4.3.1 Blending Irrigation Water Supplies.- 8.4.4 Cyclic Irrigation Method.- 8.4.5 Blending vs. Cyclic Practices.- 8.5 Conclusions.- References.- 9 Irrigation with Treated Sewage Effluents.- 9.1 Introduction.- 9.2 Need for Preapplication Treatment.- 9.3 Municipal Wastewater (Sewage) Characteristics.- 9.3.1 Wastewater Sources.- 9.3.2 Wastewater Flow Rates.- 9.3.3 Wastewater Constituents and Compositions.- 9.4 Municipal Wastewater Treatment and Effluent Characteristics.- 9.4.1 Preliminary Treatment.- 9.4.2 Primary Treatment.- 9.4.3 Secondary Treatment.- 9.4.3.1 High-Rate Biological Processes.- 9.4.3.2 Low-Rat…