Predicting the potato (Solanum tuberosum L.) yield under climate change using DSSAT model and CMIP6 emission scenarios

Aim of the study: Climate change poses one of the most significant threats to global food production, especially for water-intensive crops such as potatoes. This study aimed to assess the impacts of climate change on the yield and water productivity of potato (Solanum tuberosum L.) in the Ardabil region of Iran. Area of study: The research was conducted in the Ardabil region, located in northwestern Iran, a major potato-growing area characterized by diverse climatic conditions. Material and methods: Crop coefficients for five potato cultivars were calibrated and validated using field experiment data within the Decision Support System for Agro technology Transfer (DSSAT)-SUBSTOR-Potato model. Climate projections were derived from CMIP6 models, and MRI-ESM2-0 was identified as the most reliable model for the region. The LARS-WG6 model was used for downscaling the climate data. Simulations were conducted under the SSP2-4.5 scenario, and deficit irrigation levels (85% and 70% of full irrigation) were evaluated for late-maturing cultivars (‘Savalan’, 397081-1, and 397082-10). Main results: Model validation demonstrated a high level of accuracy in simulating potato yield and water productivity under different climatic and management conditions. Climate projections indicate a 3.68% increase in mean temperature and a 25.4% decrease in annual precipitation by the end of the 21st century. Elevated atmospheric CO2 concentrations exhibited complex interactions with potato growth. Tuber yield and water productivity are projected to decline by up to 18.5% and 12.3%, respectively. Using late-maturing cultivars with deficit irrigation helped reduce these losses, enhancing yield and water productivity by approximately 15% and 10%, respectively, in the 2030s and 2060s compared with the 2090s. Research highlights: The DSSAT-SUBSTOR-Potato model proved to be a reliable tool for assessing the impacts of climate change and evaluating management strategies. The integration of climate-resilient cultivars (‘Savalan’, 397081-1, and 397082-10) with optimized irrigation practices can effectively mitigate negative climate effects. The findings offer scientific insights for agricultural policy and food security strategies in climate-vulnerable regions.