Influence of vegetation types on soil physicochemical and biochemical properties in naturally recovering riverbank sand mining sites
摘要
Natural recovery is a vital strategy for rehabilitating degraded ecosystems, yet the mechanisms by which pioneer vegetation types differentially drive soil development in harsh environments like riverbank sand mining sites remain poorly understood. In this study, plant nutrient characteristics, soil physicochemical and biochemical properties of four vegetation types, namely, Artemisia scoparia, Saccharum arundinaceum, Imperata cylindrica, and solitary trees, in the naturally recovering sand mining sites along the upper Huai River Basin were investigated. The findings revealed a consistent “surface enrichment” effect, with soil physicochemical properties significantly better in the 0–20 cm layer than in the 20–40 cm layer across all vegetation types. The effects of vegetation types on soil properties were profound and divergent. Soil total carbon (TC) content was highest under I. cylindrica (15.24 ± 2.92 g/kg), which was 3.1 times the TC under A. scoparia. Plant total nitrogen content (TN) varied dramatically, with A. scoparia (7.16 ± 0.85 g/kg) containing approximately twice the tissue TN content of the other vegetation types; Soil multifunctionality was directly regulated by both vegetation type and soil depth, with the effects of vegetation mediated by soil chemical properties, and the effects of depth mediated by chemical properties and enzyme activities. Coarse particulate carbon was the key driver, explaining 36.5% of the variance in soil properties. Collectively, vegetation facilitated recovery via a “trading carbon for nitrogen and phosphorus” strategy, enhancing carbon cycling to overcome nutrient limitations. This study provides actionable guidance for assisted restoration by identifying I. cylindrica for rapid surface soil enrichment and solitary trees for deep structure improvement, suggesting a staged planting strategy.