Combining infiltration hole and mulching techniques with fish-scale pits effectively improved soil water storage in semiarid areas with shallow buried bedrock (Pisha Sandstone) in China

Abstract

Effectively regulating slope runoff and infiltrating maximum rainwater are essential to reduce soil and water loss, and promote vegetation restoration in the Pisha Sandstone areas of China, which are semiarid areas with shallow buried bedrock. However, the effects of individual or combined rainwater regulation measures, such as infiltration holes, mulch, and fish-scale pits (a semicircle-shaped pit), on soil water infiltration and restoration in such regions have not yet been fully explored. In this study, the responses of soil water to rainfall in the 0–1.6 m soil layer was investigated through in situ monitoring during the two main rainy seasons under four rainwater regulation treatments in the Pisha Sandstone area of China covered in thin soil layer (0–0.3 m): fish-scale pits with grass mulching and infiltration holes (PGH), fish-scale pits with grass mulching (PG), fish-scale pits without mulching (P), and slope land (control, CK). The results have shown that because of the relatively low permeability (0.08–0.17 m d−1) of Pisha Sandstone, individual torrential rainfall events (63.2 mm) increased the soil water only in the 0–0.3 m layer after 3 days under the CK, P, and PG treatments. However, the PGH treatment simultaneously and significantly increased the soil water in the 0–0.3 m and 0.7–0.8 m layers. Compared with the CK treatment, rainwater replenishment depths under the P, PG, and PGH treatments increased from approximately 0.4 m to 0.9 m, 1.0 m, and 1.1 m, respectively, and the average soil water storage increased by 27 mm, 34 mm, and 50 mm, respectively, in the 0–1.6 m soil layer. Moreover, the PGH treatment enhanced rainwater storage in deep soil (0.6–0.9 m), which decreased the potential for water loss by evaporation. We concluded that the PGH treatment was effective in increasing soil water storage and reducing soil erosion in areas with shallow buried bedrock.