Irrigation requirement of greengram and chickpea under changing climates of Dharwad district ofKarnataka under rainfed conitions using CROPWAT model

Abstract

Greengram and Chickpea are the major protein rich grain legumes predominately cultivated in Dharwad districtof Karnataka. The present study was aimed to determine the water requirement of greengram and chickpea using CROPWATmodel for Dharwad. The decadal analysis was done under past (1991-2020) and projected climate (2021-2050) as per therecommended practices of UAS, Dharwad across four dates of sowing from 07th June to 28th June at weekly interval forgreengram and four dates of sowing from 01st October to 15th November at quarterly interval for chickpea. Model simulatedan increase of 42.6 mm and 37.5 mm of ETc and IR respectively, and decrease of 91.4 mm of ER under projected climatesfor greengram. In chickpea model simulated an increase of 61.0 mm of ER and a decrease of 71.4 mm ETc and 108.1 mm ofIR under projected climates when compared to past for chickpea. Under projected climates in greengram, the yield underrainfed condition and average number of irrigations reduced by 10 % and 8.3 % respectively on black soil and on red soil 3.8% and 140 %, respectively compared to past climates. In chickpea, under projected climates, the yield under rainfedcondition and average number of irrigations reduced by 18.5 % and 42.9 %, respectively. Sowing late i.e., on 28th June ingreengram and sowing early i.e., on 01st October in chickpea under projected climate simulated the least reduction in yieldand less number of irrigation would be required for Dharwad district of Karnataka State