Climate change impacts on cotton growth in Northern Xinjiang and irrigation strategies for water-saving and stable yield: A DSSAT-CROPGRO-cotton modeling study (2026–2100)

Assessing the impact of future climate change on cotton production in Xinjiang and proposing corresponding irrigation management strategies is of great significance for ensuring the sustainable and high-quality development of Xinjiang’s cotton industry under severe water constraints. Based on projections from six global climate models under three representative greenhouse gas emission scenarios—SSP126, SSP245, and SSP585—this study utilizes the calibrated CROPGRO-Cotton model and CMIP6 daily climate data to forecast future trends in cotton phenology, seed yield, water consumption, and water productivity in the Changji, Xinjiang. The results indicate that air temperatures and annual precipitation in this region are increasing year by year, and the climate is becoming more humid. Future climate change will shorten the flowering and maturation periods of cotton, while seed cotton yield and water productivity will show an overall downward trend over time, reaching their maximum values in the near future (2026–2050) under the SSP245 scenario. As emission scenarios intensify, irrigation volumes and water consumption across all hydrological year types show an upward trend. Under the SSP126 scenario, seed cotton yields are highest in drought, normal, and wet years, while the SSP585 scenario results in the most significant yield reductions. With regard to the goal of water conservation and stable cotton production under plastic-film drip irrigation in Changji, Xinjiang, during drought years, medium, low, and high emission scenarios can all maintain relatively high seed cotton yields under quota-based irrigation regulation. During normal-water years, under quota-based irrigation regulation, medium, low, and high emission scenarios can all moderately reduce irrigation volumes (SSP126: −15 mm; SSP245: −40 mm; SSP585: −100 mm) to maintain relatively high yields. In wet years, under quota-based irrigation regulation, the medium, low, and high emission scenarios can all appropriately reduce irrigation volumes (SSP126: −12 mm; SSP245: −40 mm; SSP585: −180 mm) to maintain relatively high yields. The findings of this study can serve as a reference for adjusting irrigation strategies and optimizing regional water allocation in the cotton industry of the Changji region in Xinjiang in response to climate change risks, thereby helping to promote sustainable agricultural development.