Abstract Vegetation restoration typically aims to control and restore collapsing gullies, which are prevalently and seriously eroded areas in South China. However, its effectiveness has rarely been evaluated, especially on steep colluvial deposits and during the prevalent high-intensity precipitation events. The effects of Melinis minutifora and Chrysopogon zizanioides on slope erosion, and the contributions of canopy, biocrusts, and roots were investigated in this study via rainfall simulation experiments. M. minutifora and C. zizanioides effectively reduced soil sediment yield rate (SR) on steep colluvial deposits by 98.1% and 86.6%, respectively. Overall, lower and denser canopies and greater fine root volumes indicated better performance of M. minutifora compared to C. zizanioides. Canopies of both plants exerted the strongest effects and contribution rates for reducing the SR and apparent interrill erodibility, while the effects and contribution rates of biocrusts were slightly higher than those of roots on average. These results highlight the importance of low plant canopies, fine roots, and the protection of biocrusts toward the reduction of rainfall erosion. The results add to the optimization of soil conservation and management practices for steep colluvial deposits.

中文翻译：

---

近地表组分对陡峭花岗岩红壤崩积沉积物土壤侵蚀的影响

摘要 植被恢复的主要目的是控制和恢复塌陷的冲沟，这些冲沟是华南地区普遍而严重的侵蚀地区。然而，它的有效性很少被评估，特别是在陡峭的崩积沉积物和普遍的高强度降水事件期间。本研究通过降雨模拟实验研究了小花楸树和金针草对坡面侵蚀的影响，以及冠层、生物结皮和根系的贡献。M. minutifora 和 C. zizanioides 分别有效地将陡峭崩积沉积物的土壤沉积物产率 (SR) 降低了 98.1% 和 86.6%。总体而言，与 C. zizanioides 相比，较低和较密的冠层和较大的细根体积表明 M. minutifora 的性能更好。两种植物冠层对降低SR和表观间可蚀性的作用和贡献率最强，而生物结皮的作用和贡献率平均略高于根系。这些结果强调了低植物冠层、细根和保护生物结皮对减少降雨侵蚀的重要性。这些结果有助于优化陡峭崩积沉积物的土壤保持和管理实践。