Water-Saving Potential of Different Agricultural Management Practices in an Arid River Basin

Abstract

Water scarcity threatens food security in arid areas, highlighting the importance of water-saving agriculture for food production. Agricultural management practices are developed to improve water-use efficiency, and their water-saving effects are generally evaluated at the field scale rather than the regional scale. To figure out the regional water-saving potential of irrigation methods and mulching practices, the FAO AquaCrop model was first calibrated and validated at the three exper-imental stations. With aggregating spatial information, a distributed model was constructed and validated in a typical arid river basin of northwest China. Twelve combinations of soil mulching (plas-tic and straw) and irrigation methods (basin, furrow, drip, and subsurface drip) were simulated using the model to evaluate the effect of agricultural management practices on crop evapotranspiration (ET), crop water productivity, and regional water consumption. The results showed that soil mulching, advanced irrigation methods, and their combinations reduced noneffective soil evaporation (E) and the E/ET ratios and improved crop water productivity. Plastic mulching combined with subsurface drip irrigation is the most promising practice, increasing the crop water productivity of seed maize and spring wheat by 18.2% and 11.1% on average and reducing regional crop water consumption by 7.7% (75.0 million m3) and 7.4% (72.7 million m3), respectively. The reduction in irrigation water extraction ranged from 20.6% under furrow irrigation with straw mulching to 68.7% under subsurface drip irrigation with plastic mulching. This study quantitatively assessed the water-saving potential of soil mulching, irrigation methods, and their combinations to reduce agricultural water use, offering practical implications for the management and development of water-saving agriculture in arid areas.