SIMULATING THE EFFECT OF DEFICIT IRRIGATION ON EGYPTIAN CLOVER YIELD AND WATER PRODUCTIVITY

Yield-Stress model was calibrated and validated for clover yield and consumptive use data of four-year field trials at Beni Sweif Governorate, Egypt under two treatments of irrigation water quality (fresh and drainage). The goodness of fit between measured and predicted values by the model was tested by calculated percent difference between measured and predicted values of yield and consumptive use, in addition to root mean squared error and Willmott index of agreement. Then, the model was used to predict the effect of four deficit irrigation treatments (95, 90, 85, and 80 % of full irrigation). Water productivity was calculated under all cases. The results showed that the model performance was highly acceptable in predicting clover yield and consumptive use. Low yield losses occurred under both fresh and drainage deficit irrigation water as a result of 10 % irrigation water saving. Water productivity was gradually increased under all deficit irrigation treatments, which suggested that there is a high potentiality to save an ample amount up to 20 % of the irrigation water to be used in cultivating more lands.