ABSTRACT
Because of limited water resources in Egypt, all irrigation users must work towards effective rationalization of irrigation at farm level. The simple procedure is to have knowledge of how much water should be applied. Irrigation can significantly increase soybean seed yield, [10] and can increase profits [17] under soil moisture deficit conditions. However, Cox and Jolliff [2] found that soybean plants are unable to withstand prolonged droughts. They also found that evapotranspiration of soybean plants was 17 and 68% less in deficit-irrigated and nonirrigated plants than that for the well-irrigated plants, respectively.
