Synthesis of a simplified water use simulation model for predicting wheat yields

A simplified water use simulation model has been developed that predicts components of field water balance for wheat using information on atmospheric evaporative demand, extractable water and draining characteristics of soil profile, leaf area development, root growth characteristics, and soil wetting events. The model accounts for soil water flow with redistributing water below field capacity and estimates layerwise water use. Predicted evaportranspiration and soil water content in different soil layers matched well with the measured values for a wide range of water management situations and the root‐meansquare error varied between 10 and 15%. Transpiration‐yield relations, estimated through a multiplicative approach, showed that booting‐heading phase of wheat development was most sensitive to water stress. Validation of this model against independent data was reasonably well, thereby suggesting that the model dependably predicts grain yield. Small data required for the operation of the model increase its capability as management tool for efficient on‐farm water use.