Irrigation Scheduling and Estimating Yield Reduction in Chickpea under Rainfed Condition and Changing Climate of North Interior Karnataka

Abstract

Chickpea is one of the major legumes predominately cultivated in North Interior Karnataka (NIK). This simulation study using CROPWAT model aimed at quantifying yield reduction under rainfed conditions and proper irrigation scheduling in chickpea variety BGD-103. This would help NIK farmers in tapping the potential yields of this crop through proper irrigation management. Crop management input in the model was based on the recommended practices of UAS, Dharwad, across four dates of sowing from 1st October to 15th October at quarterly intervals on black clay soil. The simulated outputs were analyzed at decadal interval for both past (1991-2020) and projected climate (2021-2050). Under past climate, two irrigation was simulated i.e., one irrigation at 40-45 days after sowing (DAS) and another at pod filling stage (70 DAS). The number of irrigations decreased by one under projected climate i.e., only one irrigation at 45 DAS. Yield reduction in rainfed conditions on black clay soil under past climate was 31.6 %, which in contrast, decreased by 16.4 % under projected climate and is presented against spatial distribution across NIK. Sowing early i.e., on 01st October under projected climate (2021-2050) simulated the lowest yield reduction (rainfed) and require fewest irrigations across 12 districts of NIK.