Rainwater infiltration and nutrient recharge system significantly enhance the growth of degraded artificial forest in semi-arid areas with shallowly buried soft bedrock

Abstract

The improvement of deep soil water and nutrient pools by maximizing in situ rainwater resource utilization and soil nutrient recharge is an important approach to promote slope vegetation restoration in the Chinese Loess Plateau, especially in areas with shallowly buried soft bedrock (Pisha Sandstone). However, the effects of integrated slope engineering measures (fish scale pits (a semicircle-shaped pit), infiltration holes, organic fertilizer) on runoff utilization, nutrient restoration and vegetation growth are not well known. This study combined rainwater infiltration and nutrient recharge (RINR), and evaluated the effect of RINR on soil water, organic carbon, total nitrogen storage and vegetation growth in a field experiment in slope artificial forestland (David peach, Prunus davidiana Franch) one year later (from 2018 to 2019). Four treatments: (1) rainwater infiltration and nutrient recharge (RINR) system (fish scale pit + infiltration hole + hole filling with 30% organic fertilizer and 70% surface loess, PHF treatment), (2) fish scale pit + infiltration hole + filling surface loess (PH treatment), (3) pure fish scale pit (P treatment) and (4) natural slope land (control, SL treatment, CK). The results showed that, compared with the control (162 mm), PHF, PH and P treatments increased the soil water storage of 0–100 cm soil layer by 37 mm, 76 mm and 30 mm, respectively. The RINR system (PHF treatment) had a significantly higher restoration effect of SOC and STN value than other treatments in all soil profiles (0–100 cm), especially at 40 cm. Compared with the control (2.42 kg/m2, 0.28 kg/m2), the RINR system 0–40 cm soil layer soil organic carbon storage increased by 320%, and total nitrogen storage increased by 129%. Meanwhile, changes in height of tree (David peach), crown width and annual branch length under RINR system increased by 0.18 m, 0.30 m and 0.33 m, respectively. Overall, the RINR system is an effective approach for enhancing the growth of degraded revegetation. This system is conducive to mitigating the water and nutrient scarcity and maintaining the persistence of vegetation restoration in arid and semi-arid areas with shallowly buried soft bedrock.