Improved methods for agricultural and water resources planning and management

A set of novel methodologies for planning and management of agricultural and water resources systems is developed. These methods are applicable at scales ranging from a local site over one growing season to large systems across decadal time scales. The research draws on several disciplines including crop science, hydrology, climatology, optimization of dynamical systems, uncertainty analysis and management, and policy evaluation.; New irrigation planning techniques are formulated and evaluated, based upon modeled physiological drought stress and differential yield response to incremental irrigation. The latter is found to provide near-optimal results, and both methods lead to significant improvements over existing irrigation planning methods. The algorithms are applied to derive yield-irrigation response functions.; Spatial distribution of irrigation water is performed at various spatial scales for a large set of policies. These policies have varying focus on the objectives of optimality and equity. Policy performance is evaluated, and assessments are made regarding crop yield and irrigation distribution.; The role of temporal-climatic variability on agricultural water resources systems is discussed, and available techniques for near-term climate uncertainty reduction are evaluated. Agricultural and water resources response to potential scenarios of climate change are assessed for three general circulation model (GCM) scenarios. All of the methods developed are applied to a case study of the Lake Victoria basin in East Africa and are found to provide useful information for agricultural and water resources planning.