Assessment on water requirement and irrigation scheduling in Field Pea under elevated thermal regimes: A Simulation Study

Abstract

The present experiment was laid out on Field Pea (cv. AP 3) at the research farm of Bidhan Chandra Krishi Viswavidyalaya, Kalyani, Nadia, West Bengal during rabi seasons of 2017-18 and 2018-19 to estimate the ETo and water requirement from Pea field using CROPWAT 8.0 model which will eventually help farmers in irrigating the crop in future also. Seasonal mean reference crop evapotranspiration was relatively higher (2.12 mm day-1) during first season than the second one (2.04 mm day-1). Radiation use efficiency has been found to be directly proportional to the ETo rate. Model derived total irrigation requirement and actual crop evapotranspiration remained maximum as 159.3 mm and 161 mm respectively during rabi 2017-18. Increment of temperature by 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 oC from the current scenario, resulted in increasing the seasonal ETo by 1.44, 2.40, 3.84, 5.76, 6.73 and 8.17%, respectively and water requirement by 2.41, 5.40, 7.56, 10.16, 13.02 and 14.54% in alike order. Two specific crucial crop growth stages viz. initial (7-10 DAS) and mid development (35-40 DAS) were simulated based on critical depletion for scheduling irrigation under already over exploited water resource zones. Therefore, the study concluded that need based judicious irrigation supplementation at critical stages could be a realizable option for effective planning and management of moisture regimes at optimum level in view of persisting climate change conditions.