Exploring the nexus of grain production and climate variability under nitrogen and hydrothermal regimes using CERES-wheat model

Field experiment was conducted at Punjab Agricultural University, Bathinda from 2017-18 to 2019-20 to evaluate the growth and yield of wheat under varying sowing dates (Nov. 15, Nov. 30 & Dec 15), irrigation regimes (IW: CP = 0.6, 0.8, & 1.0), and nitrogen levels 80% RDN, RDN & 120% RDN). Timely sowing (15 November) resulted in significantly highest grain yield (5090 kg ha-1) and delay in sowing caused reduction in yield by 2.83 % and 9.91 % in crop sown on 30 November and 15 December respectively. Yield and yield attributes were found to increase with increase in irrigation and nitrogen levels. The highest yield was achieved with 15 November sowing, IW: CPE ratio 1.0 and 120% RDN. The sensitivity of the validated CERES-wheat model to increase in temperature by 0.7, 1.2, 1.5 0C and CO2 concentration by 435, 460, 500 ppm, as projected for years 2030, 2040 and 2050 respectively, revealed reduction in the wheat yield. The combination of 15 November sown crop, irrigation at IW:CPE ratio 1.0, and recommended dose of nitrogen showed resilience against increasing CO2 concentration and temperature rise.