Evaporation effect of infiltration hole and its comparison with mulching

Abstract

Reducing ineffective evaporation of soil water is an important way to relieve drought in semi-arid rainfed agricultural areas. An infiltration hole is a supplemental measure for slope rainwater harvesting measure and is commonly used in vegetation restoration and orchard management of slopes. However, the evaporation effects of infiltration holes are unclear. In this study, we determined the evaporation effects of infiltration holes under a high initial soil water content and compared the differences in inhibition of soil evaporation among infiltration holes, mulching, and their combination after a rainstorm event. The results showed that the infiltration holes at different depths increased soil daily evaporation in the first 26 days under the high initial soil water content, after which it decreased. Compared with the control, the average daily evaporation while covering the top surface and the hole (sidewall and bottom) decreased by 74.3% and 4.3%, respectively. After the rainstorm event, cumulative evaporation (97 days) significantly decreased by 42.0% and 34.0% under the infiltration hole compared to gravel mulching and branch mulching, respectively. Overall, the infiltration hole increased soil evaporation at the early stage. Soil water mainly evaporated through the top surface of the soil column rather than through the hole itself. In the long term after rainstorms, infiltration holes have better effects in inhibiting evaporation than mulching. Our findings determine the evaporation effects of infiltration holes in the process of harvesting rainwater to replenish soil water in semi-arid rainfed agricultural areas.