Impact of Climate Change on Future Wheat Production and Possible Mitigation Strategies: Experimental and Modeling Study

The rising challenges by climate change for sustaining wheat production demand the use of innovative strategies regarding available inputs (water and nitrogen) under existing production systems. The study was conducted in two consecutive years (2020–2021 and 2021–2022), and it investigates the impact of varying nitrogen doses (N80: 80 kgN·ha−1 and N100: 100 kgN·ha−1) and salinity of irrigation water [fresh canal water (Fr): EC=0.81 dS·m−1 and tube well water (Tb): EC=4.12 dS·m−1] for wheat production to train the SALTMED model for optimization through hypothetical simulation. The results from field experiments demonstrated significantly higher grain yield, dry matter, plant height, and water productivity under treatments with Fr compared with Tb at similar nitrogen levels; treatments under N100 (100 kgN·ha−1) performed better than that under N80 (80 kgN·ha−1). The SALTMED model was calibrated for grain yield, dry matter, plant height, and soil moisture, and it showed robust performance during validation, with the values of root-mean square error (RMSE), normalized root-mean square error (NRMSE), coefficient of determination (R2), and coefficient of residual mass (CRM). The values of RMSE were 0.22 T·ha−1, 0.93 T·ha−1, 2.73 cm, and 0.52% for grain yield, dry matter, plant height, and soil moisture, respectively. Also, the NRMSE, R2, and CRM ranged from 0.16 to 0.51, 0.88 to 0.90, and −0.04 to 0.02, respectively. Future climate scenarios were developed against two representative concentration pathways (RCPs), i.e., RCP4.5 and RCP8.5, that predicted a decrease in wheat grain yield and dry matter ranging from 3.3% to 12.5% and 2.5% to 12.83%, respectively, under RCP4.5 and from 5.5% to 18.0% and 3.8% to 16.3%, respectively, under RCP8.5. To mitigate the adverse effects of climate change, hypothetical scenarios were simulated under, increased nitrogen doses (N125: 125 kgN·ha−1, N150: 150 kgN·ha−1, N175: 175 kgN·ha−1, and N200: 200 kgN·ha−1). These scenarios suggested that increasing nitrogen doses up to 75% could significantly counteract the negative impacts of climate change, improving grain yield and dry matter by 21%–25% and 23%–27% under future climate conditions.