Rainwater collection and infiltration (RWCI) systems promote deep soil water and organic carbon restoration in water-limited sloping orchards

Measures that maximize in situ infiltration and utilization of rainfall are urgently needed on the Loess Plateau to minimize problems associated with drought and soil erosion, and to improve the sustainability of arid and semiarid agricultural production in this region. Here, we present a two-year field assessment of two rainfall control systems-a rainwater collection and infiltration (RWCI) system and a semi-circular basin (fish-scale pit, FSP)-that could improve soil water storage (SWS) and deep soil organic carbon (SOC) levels in apple (Malus pumila Mill.) orchards on a slope. The RWCI system performed better than the FSP system at conserving and utilizing rainwater resources and conserving rhizosphere soil water to meet the water demand of commercial apple orchards. The RWCI system decreased the soil water storage deficit (W-D) and enhanced the SOC content of the root zone due to precipitation, whereas the FSP had little effect. The RWCI system (RWCI60 and RWCI80) significantly increased soil water and SOC contents by 73 % and 81 %, respectively, relative to the control. The design depth of the RWCI system should match the root distribution of adjacent crops to make RWCI a recommended sustainable approach for maximizing the utilization of rainwater resources and the conservation of rhizosphere soil water in standing orchards. This system should help to mitigate the effect of climate change on water scarcity in arid and semi-arid regions, with potential for application in other orchard crops and regions.