Minimizing ineffective water consumption during fallow periods for sustainable agricultural water use in arid salinized regions, northwest China

Irrigation during fallow periods is essential for crop production in arid salinized regions, as it helps reduce soil salinity and improve soil moisture. However, it exacerbates agricultural water scarcity, which fluctuates dynamically under the background decreasing water supplies and shifting in crop structure. Despite its importance, researches on the impact of irrigation in the non-growing season on water scarcity are limited. This study evaluated the compositions of water consumption in the non-growing season under different crop structures in Hetao Irrigation District, a typical arid salinized region, using blue water footprint method and based on leaching requirement theory. And the blue water scarcity index was applied to assess the impact of blue water consumption in non-growing season on agricultural water scarcity, under different water supply and consumption scenarios. Results showed that the average blue water footprint in non-growing season was 3245.48 m³/hm², accounting for 39% of the total blue water footprint in the entire production. While, the effective blue water footprint for salts leaching and incorporation in crop initial stage constituted only 32%, ineffective blue water footprint related evaporation accounted for 68% of blue water footprint in the non-growing season. Ineffective water consumption during fallow periods significantly increased blue water scarcity. Crop structure adjustments did not significantly reduce ineffective water consumption or alleviate water scarcity. However, reducing ineffective water consumption during fallow periods could effectively alleviate water scarcity, with potential water savings of up to 39%. The reduction of ineffective water consumption warrants further investigation, particularly to meet the needs of salts leaching and moisture conservation. This study provides theoretical support for the sustainable utilization and management of agricultural water in arid salinized regions.