Crop Water Stress Indices and Evapotranspiration Estimation

The Crop water stress index (CWSI) and water deficit index (WDI) of wheat crop were developed using canopy air temperature difference (Tc-Ta)and vapour pressure deficit for scheduling irrigation. These values were varied with the change in soil moisture content and indicated water stresses of crop, which coincided with the moisture sensitive growth stages of wheat crop. Study was conducted in the Kangsabati Irrigation command, India for irrigation scheduling and crop yield modelling using remote sensing and GIS. The crop coefficients of wheat crop were generated using remote sensing based SAVI values. The ETo values were computed as per the Penman- Monteith method FAO-56. The evapotranspiration (ETc) computed using ETo and the Kc generated from SAVI values of wheat crop. Wheat crop yield models were developed using the remote sensing derived AREASUM of SAVI values. The developed yield models have predicted the wheat crop yield for the study command. The performance of irrigation command was evaluated by computing various irrigation efficiencies using remote sensing generated yields and water demand of crop.