Quantifying the Irrigation Requirements for Major Crops Under the Influence of Climate Change in a Semi-Arid Region

Climate change threatens agricultural sustainability, especially water resource management. This study comprehensively analyses how climate change impacts irrigation water needs in India's vital Girna command area, which lies in a semi-arid region, where a decision support tool with climate scenario analysis was integrated, incorporating five different climate models with region-specific agricultural data to evaluate future irrigation demands under various climate change scenarios. The maximum and minimum temperatures will rise under two representative concentration pathways (RCP) scenarios, with RCP 8.5 projecting a more significant increase than the RCP 4.5 scenario. Reference evapotranspiration (ETo) will also increase compared to the base period, reaching its maximum in May and minimum in December across all climate models. However, crop water requirements should remain stable or slightly decrease, with a maximum occurring in October and a minimum in March across all climate models. Depending on the climate model and RCP scenario, maximum effective precipitation will vary and most likely occur in July. Maximum gross irrigation requirements may decrease under RCP 8.5 for the base period, particularly in November. These findings significantly impact agricultural planning, water management, and climate change adaptation strategies. This study can assist stakeholders in making informed decisions for sustainably managing water resources in the Girna command area and beyond.