Climate change impacts on wheat yield: a multi-modeling case study of central Punjab, Pakistan

In this study, we integrated 2 crop models-the Agricultural Production Systems Simulator (APSIM) and the Decision Support System for Agrotechnology Transfer (DSSAT) - with regional climate models (RCMs) of the Coordinated Regional Climate Downscaling Experiment (CORDEX) to examine the best combinations of sowing and irrigation practices to combat the impact of future climate change on winter wheat yield and phenology in Punjab Province, Pakistan. Three RCMs were selected, and climate variables were projected for early (2017-2040), mid- (2040-2069) and late-century (2070-2100) periods. Combinations of different irrigation amounts, nitrogen applications, planting densities and shifts in planting times were studied to overcome the reduction in wheat yield caused by climate change. Field trial data and observed climatic data were used for the calibration and validation of APSIM and DSSAT, and these data were replaced with RCM scenarios after validation of the models to quantify the effects of climate change on yield and phenology. The models projected an increase in precipitation (17.14-61.72 %) as well as in maximum (5.15 degrees C) and minimum temperatures (5.81 degrees C) in the study area. Moreover, under RCP4.5 and RCP8.5, both crop models depicted a 2.81-31.0% reduction in wheat yield during the 3 future climate scenarios compared to the baseline yield. Different adaptation strategies are suggested to combat the effects of climate change on crop yield. Results indicate that in the future, wheat yield can be increased by up to 21.11 and 7.03% by increasing the fertilizer application rate to 150 kg N ha(-1) and planting 10 d earlier, respectively. This study shows that combining altered planting time and proper nutrient management may result in higher wheat production under different climate change scenarios.