Water balance model for paddy fields under intermittent irrigation practices

A water balance model applicable to intermittent irrigation practice in rice fields was developed. The model inputs consist of climatic data and soil parameters. The model is formulated to simulate various processes such as evapotranspiration, deep percolation, surface runoff and depth of irrigation water to be applied on a daily as well as a seasonal basis. It also simulates daily pending depth in the field. Both saturated and unsaturated water flow concepts were incorporated into the model to predict deep percolation loss during wet and dry periods of the field. The model was validated using data collected from field experiments. The details of model development and validation are outlined in this paper.