半干旱黄土区植被恢复对土壤团聚体稳定性及抗侵蚀能力的影响

土壤水稳性团聚体强烈影响土壤过程和功能，是反映土壤质量和土壤抗侵蚀能力的重要指标。为探究半干旱黄土区植被恢复对土壤抗侵蚀能力的影响，以甘肃省定西市龙滩流域为研究区，选取3种恢复方式（天然荒草、自然恢复、人工恢复）7种植被类型（大针茅草地、长芒草草地、赖草草地、苜蓿草地、柠条灌丛、山杏林以及油松林）为研究对象，通过测定0-20 cm、20-40 cm和40-60 cm土壤水稳性团聚体，分析土壤团聚体组成、稳定性及抗侵蚀能力特征。结果表明：1）不同恢复方式不同植被类型间土壤水稳性团聚体稳定性差异显著（P<0.05），自然恢复方式的土壤水稳性团聚体平均重量直径显著高于天然荒草和人工恢复方式，且7种植被类型土壤大团聚体质量百分比均在67.97%-90.12%之间；人工恢复方式土壤水稳性团聚体稳定性较差，其中油松林稳定性最差。2）土壤团聚体破坏率和土壤抗侵蚀能力均表现出自然恢复方式更有利于土壤结构稳定性的提高。3）土壤水稳性大团聚体含量越高，土壤团聚体越稳定，土壤结构稳定性就越好；平均重量直径与土壤可蚀性因子K值呈极显著性负相关（P<0.01）。本研究结果表明自然恢复方式能够显著提高土壤团聚体的稳定性，从而提升土壤的抗侵蚀能力，建议当地在未来植被恢复规划中采取自然恢复方式更有利于生态恢复的有效进行。

Effect of vegetation restoration on stability and erosion resistance of soil aggregates in semi-arid loess region

Soil water-stable aggregates strongly affect soil process and function, which is an important index to reflect soil quality and soil erosion resistance. In order to explore the effect of vegetation restoration on soil erosion resistance in semi-arid loess region, in this study, through three restoration methods (natural grassland, natural restoration, artificial restoration) and seven vegetation types (Stipa grandis grassland, Stipa bungeana grassland, Leymus secalinus grassland, Medicago sativa grassland, Caragana korsinskii shrub, Armeniaca sibirica forest and Pinus tabulaeformis forest) were selected in the Longtan catchment of Dingxi in Gansu Province. The composition, stability and erosion resistance characteristics of soil aggregates were analyzed by measuring 0-20 cm, 20-40 cm and 40-60 cm soil water-stable aggregates. The results showed that:1) there are significant differences in the stability of soil water-stable aggregates among different vegetation types and different restoration methods (P<0.05). The average weight diameter of soil aggregates in natural restoration grassland was significantly higher than that in natural restoration and artificial restoration vegetation, and the mass percentage of soil macroaggregates of the seven vegetation types was 67.97%-90.12%. The stability of soil water-stable aggregates under artificial restoration was poor, among which the stability of Pinus tabulaeformis forest was the worst. 2) The destruction rate of soil aggregates and the ability of soil erosion resistance showed that the natural restoration method was more beneficial to the improvement of soil structure stability. 3) The higher the content of water-stable macroaggregates in soil, the more stable the soil aggregate, the better the soil structural stability; there was a very significantly negative correlation between soil average weight diameter and soil erodibility factor K (P<0.01). The results of this study show that the natural restoration method can significantly improve the stability of soil aggregates, thus improving the soil anti-erosion ability, so as to improve the soil erosion resistance, suggested the plant in the future.