Developing an Irrigation Scheduling Methodology

This irrigation scheduling model uses a meteorologically based equation to predict crop water use. The equation combines an energy balance function with an aerodynamic function, and utilizes pertinent meteorological variables in its derivation. Irrigation scheduling is based upon a water budget that maintains a predetermined soil moisture range within the crop root zone. h precise water balance bookkeeping system monitors soil water inputs and outputs. Irrigation scheduling is accomplished by evaluating present soil moisture conditions relative to a 7 – day prediction of crop water use. The model has been tested against previously determined values of evapotranspiration for corn and winter wheat. Results of these comparisons are within 0.4 percent for corn and 4.6 percent for winter wheat.