Assessment of Climate Change Impact on Potato-Potato Cropping System Under Semi-arid Environment and Designing of Adaptation Strategies

Climate change in the form of heat waves, torrential rains and floods is showing impact on the food security in Pakistan. Potato is the main cash crop of the region affected by climate change. However, impact assessment of climate change for the potato-potato cropping system has not been studied yet. Hence, in the present study, we studied the impact of projected climate change and key adaptation options on the potato-potato cropping system using the DSSAT-CSM-SUBSTOR-Potato model. The model was calibrated using 2019 spring and fall season field experiments data, while evaluation was made using spring and fall season data of 2019 and 2020 respectively. After calibration and evaluation, model sensitivity analysis for carbon, temperature, water and nitrogen (CTWN) was performed, and after that, it was applied to determine the impact of climate warming and change in rainfall on spring and fall potato during mid-century. The results revealed that during the baseline period (1980–2020), maximum (Tmax) and minimum (Tmin) air temperature were increased by 0.7 and 0.8 °C during the spring growing season and by 0.8 and 0.9 °C during the autumn growing season, respectively. Furthermore, it was projected that autumn potato will be more influenced due to climate change than spring potato. Under future projections, temperature change for spring planted potato will be 2.7 to 3.8 °C for Tmin and 2.1 to 3.4 °C for Tmax. However for the autumn seasons, potato increase in maximum temperature will be from 2.4 to 3.6 °C and for minimum temperature the change will be from 2.7 to 4.0 °C. Simulation outcome showed that without adaptation strategies, tuber yield will be reduced from 23 to 29% and from 19 to 36% in spring and fall potato, respectively. While with adopting suitable adaptation strategies such as fertigation, planting date adjustment (earlier planting of spring potato by 15 days and delayed planting of fall by 20 days), higher thermal time requiring cultivars, increase of 12% in plant population and nitrogen quantity, tuber yield can be increased by 9 to 13% during spring and by 10 to 14% during autumn potato during mid-century. Therefore, farmers should adopt suitable adaptation strategies as mentioned to reduce the negative impact of climate change on potato yield.