Climate change threatens water resources for major field crops in the Serbian Danube River Basin by the mid-21st century

Serbian Danube River Basin As climate change makes weather patterns more erratic, water supply for agriculture is becoming increasingly uncertain. This is concerning in the Serbian Danube River Basin, where crops are mainly rainfed and the growing season is becoming warmer and drier. Assessing the balance between future agricultural water demand and availability in a changing climate is critical to address agricultural water scarcity. To understand how changing climate will affect water availability during 2041–2070, we used the Soil and Water Assessment Tool+ hydrological model with field-scale crop rotations and irrigated extent data and forced with regional climate model data under two representative concentration pathways (RCP4.5 and RCP8.5). Declining precipitation, increasing evaporative demand, and lack of widespread irrigation will intensify green water (i.e., soil moisture from rainfall that rainfed systems rely on) scarcity and crop water stress across the spring-planted, rainfed cropping systems in Serbia during the peak growing season. Irrigated fields, currently rare, are barely offsetting green water scarcity and crop water stress and will need to increase irrigation by 10–20 % just to maintain current levels of green water scarcity and crop water stress. These findings highlight that agricultural producers in Serbia will need to adjust agricultural practices and likely expand irrigation to tackle increased water demand, but this may reduce blue water availability. • Climate change to increase spring rain, decrease summer rain in Serbia by 2041–2070. • Water scarcity and crop stress intensify during the peak growing season, with the greatest impact in southern Serbia. • Irrigation mitigates crop water stress but may reduce blue water availability, prompting farmers to adapt their practices or expand irrigation.