Infiltration holes enhance the deep soil water replenishment from a level ditch on the Loess Plateau of China

The introduction of exotic plants with high-water consumption and high-density planting have greatly changed the deep soil water environment on the Loess Plateau of China. Slope measures can intercept runoff to change slope soil water redistribution, however, the existing measures are not enough to improve deep soil water replenishment. Infiltration holes were used as a supplement of the existing slope measures. In this study, the effects of three different measures (the control without any measures, the level ditch, and the combination of level ditch and infiltration hole) on slope runoff and deep soil water redistribution were evaluated under field conditions. The results showed that the combined measure reduced the runoff by 44.1% and the sediments by 78.6% under an intense rainfall event compared with the control. After two rainy seasons, compared with the control and the level ditch, the combined measures significantly increased the soil water storage below 50 cm in the soil layer. Combining infiltration hole with level ditch improved the deep soil water replenishment within 30 cm from infiltration hole in a horizontal plane. Overall, the single-level ditch was insufficient to improve deep soil water replenishment, and the combined measure can more effectively intercept runoff to increase the water replenishment of deep soils. Our findings provide a new thinking in regulating and utilizing slope runoff to effectively improve deep soil water replenishment in arid and semiarid areas.

Automated summary

The introduction of exotic plants with high-water consumption and high-density planting has profoundly altered the deep soil water environment on the Loess Plateau of China. Slope measures alone are insufficient in improving deep soil water replenishment, but the combination of infiltration holes with level ditches effectively intercepts runoff and increases water replenishment of deep soils. This study provides new insights into regulating and utilizing slope runoff to improve deep soil water replenishment in arid and semiarid areas.