摘要：As a widespread soil hydrological phenomenon, soil water repellency can lead to water redistribution of precipitation on the soil surface, which is related to important hydrological processes such as precipitation infiltration, surface runoff, soil erosion, and nutrient loss. However, studies on water repellency changes caused by vegetation changes are limited. Besides, the most common evaluation methods are the water drop penetration time (WDPT) and the molarity of ethanol drop (MED), but the two methods are not suitable for soils with low water repellency. This study attempts to improve the RI method for evaluating the soil water repellency index based on the soil water infiltration equation and the microdisk infiltration experiment. Based on the typical vegetation changes on the Loess Plateau of China, soil hydraulic conductivity and soil water repellency and their changes are determined in the field scale under the conditions of returning farmland to grass or forest. The results show that the surface soil hydraulic conductivity and water repellency index of the wheat field, as reference conditions, are 2.02x 10- 4-2.44x10-4 cm/s and 0.22-0.24, respectively. After conversion to woodland, they change into 0.56x10" 4-7.64x10-4 cm/s and 0.56-7.64, suggesting the hydraulic conductivity decrease and the water repellency index increase. This is potentially unfavorable for precipitation infiltration.
关键词：Soil water repellency;Water repellency index;Vegetation change
