Land Use Affects Soil Moisture Response to Dramatic Short-term Rainfall Events in a Hillslope Catchment of the Chinese Loess Plateau

To efficiently exploit rainfall resources in arid and semiarid regions, it is essential to understand the relationship between land use and the response of soil moisture to different rainfall levels. To clarify this relationship, rainfall and soil moisture in the 0- to 100-cm soil layer were monitored continuously in a jujube orchard, cropland, and grassland on the Chinese Loess Plateau between 1 July and 30 Sept. 2014 to determine how soil moisture levels respond to intense brief rainfall events (torrential and heavy rain) under each land use. Heavy rain only increased soil moisture levels in the 0- to 20-cm soil layer, irrespective of land use. However, torrential rain increased soil moisture levels in the 0- to 60-cm soil layer. Additionally, the rainfall response of soil moisture in the 0- to 10-cm soil layer of the cropland and grassland was correlated with the antecedent soil moisture: the lower the antecedent soil moisture, the quicker the rainfall response. Soil moisture in the 0- to 20-cm soil layer in the jujube orchard responded more quickly to heavy rain than to torrential rain. Finally, the use efficiency of torrential rain under all three land uses was below 55%, while that of heavy rain was as low as 20%. These findings may facilitate the development of strategies for improving rainfall utilization and land management on the Chinese Loess Plateau and other arid and semiarid areas.