典型岩溶山区植被恢复对土壤团聚体分布及稳定性的影响

Effects of Vegetation Restoration on Distribution and Stability of Soil Aggregate in Typical Karst Mountains

[目的]了解岩溶山区植被恢复对土壤团聚体分布及稳定性的影响。[方法]通过野外调查与室内分析,研究了广西壮族自治区平果县果化镇典型岩溶峰丛洼地荒地、草地、灌丛、林灌4种不同植被覆盖下土壤的基本理化性质、团聚体的分布及稳定性特征。[结果]（1）土壤中〉0.25mm的水稳性团聚体含量与土壤的容重显著负相关,与全土有机碳含量极显著正相关;（2）土壤水稳性团聚体以2~1,1~0.5和〈0.25mm粒级的含量居多。〉0.25mm粒级的团聚体,在草地、灌丛和林灌中明显高于荒地,在表层土中明显高于下层土;（3）随土层深度的增加,土壤团聚体的破坏率增大;土壤团聚体的破坏率：草地〈灌丛〈林灌〈荒地,草地和灌丛的平均重量直径和几何平均直径明显高于荒地和林灌。[结论]植被的恢复提高了团聚体的稳定性,且草地和灌丛土壤的团聚体稳定性更高,更有利于水土保持,可以作为该区域水土保持的主要植被类型。

[Objective] To understand the influence of vegetation restoration on the distribution and stability of the soil aggregate in karst mountains. [Methods] Based on the field survey and laboratory analysis, we studied the basic physical and chemical properties of the soil, the distribution and stability of the soil aggre- gate from wasteland, grassland, bushwood, forest-shrub under four different vegetation coverages in typical karst mountains in Guohua Town, Pinguo ounty, Guangxi Zhuang Autonomous Region. [Results] （1） The water-stable soil aggregate of diameter 〉0. 25 mm was significantly negative with soil bulk density and significantly positive with soil organic carbon; （2） The water-stable soil aggregate was mainly in diameter in diameter of 2~1 mm, 1~0.5 mm and d0.25 ram,and the water-stable soil aggregate of diameter 〉0.25 mm in grassland, bushwood and forest-shrub is obviously higher than in wasteland, while the topsoil is higher than the subsoil; （3） With the increase of soil depths, the destruction rate of the soil aggregate increases; the destruction rate order of the soil aggregate was. grassland 〈 bushwood 〈 forest-shrub 〈 wasteland,the mean mass diameter and gemetric mean diameter of grassland and bushwood is significantly higher than wasteland and forest-shrub. [Conclusion] The vegetation restoration increases the stability of the soil aggre- gate, and the soil aggregate stability of grassland and bushwood are more higher, which are more conducive to soil and water conservation, and can be used as the main vegetation types for soil and water conservation in this area.