Model for optimum irrigation water management

A model has been developed to determine optimal irrigation strategies for a single season. This has been achieved by using a simple relation between yield and amount of irrigation water which takes into account the effect of uniformity of water application. The main objective of the model is to provide a procedure by which farms can evaluate and compare alternative assumptions on expected water regimes for the following year in order to optimize crop rotations, crop production and farm incomes and to attain the optimum use of irrigation equipment, farmland and other resources. The method requires data that is readily available to the farmer. The application of the model to a case study is presented and then analyzed to illustrate the use of the technique and to develop some general guidelines. The results prove that the normal strategy of adopting a single value to the application efficiency ''water depth needed/gross water depth applied'' is not acceptable. This is because agronomic and economic factors should also be taken into account, plus the volume of available water on the farm and the price per cubic meter of water applied in the field.