Ice-covered soil significantly minimizes topsoil water loss in a semi-arid farmland

Flood irrigation is widely used as the most common farmland irrigation measure worldwide. However, the larger water evaporation after flooding seriously affects soil water maintenance, especially in winter and spring in the semi-arid and arid regions of north China. Hence, how to more efficiently maintain soil water content (SWC) after flood irrigation has become an important issue. This study examined whether ice-covered soil after flood irrigation can maintain high soil moisture based on a field investigation. Our results showed that the increase of SWC due to flood irrigation was markedly higher in the topsoil than in the subsoil layer, and the soil water supplement mainly happened on the cultivated horizon. Compared with the fields with no flood irrigation, SWC of the topsoil in the fields with no ice cover and with ice cover after flood irrigation increased by 56.4% and 75.6%, respectively. Farmland with ice cover presented a higher SWC than that with no ice cover after flood irrigation, and SWC increased for the topsoil and subsoil layer by 12.25% and 8.56%, respectively. Our findings proved that ice cover significantly enhanced soil water replenishment efficiency of flood irrigation to the soil layer, and the ice-covered soil after flood irrigation maintain higher SWC for both soil layers. The ice-covered soil after winter flood irrigation contributes to a better soil water habitat for farming production as an effective agricultural water management measure.