Study Of Reference Evapotranspiration Based Deficit Irrigation In The Sone Command Area In Bihar, India – A Case Study

Abstract

Deficit irrigation is a method of applying water to the field in such a manner that it maximizes the water use efficiency, so as to get higher yield per unit of irrigation water applied to the field. In the present study evapotranspiration based deficit irrigation has been analyzed for the Sone command area. For estimating reference evapotranspiration and for the crop water requirement, CROPWAT 8.0 decision support tool is used. For the present study the climatological data is obtained during the 1999-2015 in ICAR farm, Patna. The impact of deficit irrigation, yield response to water stress was evaluated by using four crop water production functions. The aim of the present study is to analyze the potential and suitability of the models in forecasting yield response of maize and wheat crops. The assessments of four crop-production functions were Jensen, Minhas et al., Stewart et al., and Rao et al. models. For maize crop, the percentage reduction in yield with ten percent in ETc by Jensen, Minhas et al., Stewart et al. and Rao et al. is 29, 3.16, 32 and 28.2 respectively. For wheat crop, the percent reduction in yield is 12.16, 1.2, 15, 14.4 respectively. By comparing these models by 10, 20, 30, 40 and 50 percent in crop evapotranspiration (ETc), the steward et al. model gives the over predicted yield values and Minhas et al. model gives the under predicted yield values. Therefore, the performance of Jensen and Rao et al. were considered better as compared to stewart et al. and Minhas et al. models to monitor crop yield response to deficit in availability of water.