Response of wheat yield, crop water requirements, and productivity to climate change (Historical simulation and future projection)

Climate change is one of the most vulnerable factors affecting the global agriculture system and it is important to investigate the crop responses to climate change for sustainable development. The present study aimed to investigate the wheat yield responses in line with the crop water requirements (CWR) and crop water productivity (CWP) to climate change in central Punjab, Pakistan. The decision support system for the Agro-technology transfer (DSSAT) model was coupled with climatic change scenarios A2 and B2 of Hadley Centre Coupled Model version 3 (HadCM3) after downscaling to project the crop water productivity, yield, and crop water requirements. Future climate projections indicate that the maximum temperature could increase to 3.9°C − 4.2°C, and the minimum temperature could increase to 1.8 ^° C-2.0 ^° C under the A2 and B2 scenarios till 2080, respectively. Average annual precipitation could increase by 4 to 10% under the A2 scenarios for the 21st century whilst under B2 scenario it increase at start of century (i.e.10.77%) and then reduce in the mid (i.e.3.37%) and end (i.e.4.14%) of the 21st century. Average seasonal crop water requirements will increase by 38 mm and 30 mm under A2 and B2 scenarios by the 2080s. Average wheat yield will decrease by 6.94% / 6.43%, 10.40% / 8.71%, and 9.45% /8.61% under the A2/B2 scenario during the 2020s, 2050s, and 2080s, respectively. Decreasing wheat yield combined with a water deficit would decrease the future crop water productivity (CWP) up to 17.76% and 14.95% under A2 and B2 scenarios, respectively.