By increasing infiltration and reducing evaporation, mulching can improve the soil water environment and apple yield of orchards in semiarid areas

Abstract

Infiltration and evaporation are two important components of soil water balance in semiarid areas. For local orchards using drip irrigation, rainfall and irrigation events have a profound impact on soil infiltration and evaporation. As an effective water conservation technique, soil surface mulching is widely used in semiarid areas. The aim of this study was to investigate the effect of mulching (e.g., horticultural fabric mulching and corn straw mulching) on soil infiltration and evaporation after irrigation and rainfall. Through field experiments, we investigated soil infiltration and evaporation during three wet-dry cycles and for a rainy month and studied the effects of mulching on soil physical properties and apple yields. The results showed that both horticultural fabric mulching (FM) and straw mulching (SM) improved soil physical properties by reducing soil bulk density and increasing porosity and that SM had a better effect. Mulching increased infiltration after irrigation and heavy rain, while SM reduced infiltration when light rain occurred. Regardless of whether the soil was in the energy-limited stage or falling-rate stage, mulching can effectively reduce soil evaporation. We determined that the threshold of soil water content (SWC) between the energy-limited stage and falling-rate stage was 22.09–22.75%. When SWC is lower than the threshold, there is a positive significant correlation between evaporation and SWC, while no significant correlation was found when it is above the threshold. Moreover, mulching effectively increased apple yields and irrigation water use efficiency (IWUE) for three consecutive years. Therefore, both FM and SM have potential for application in orchards in semiarid areas to improve soil and moisture conditions in the root zone.