[目的]探讨短期内林药复合生态系统对土壤团聚体特征的影响，可为喀斯特区植被恢复转型期的生态和经济效应综合评价提供理论依据。[方法]以李树(Prunus salicina)单一种植为对照，选取基于李树构建的四种林药系统:李+广西甜茶(Rubus chingii)、李+黄花倒水莲(Poly gala fallax)、李+金丝桃(Hypericum monogynum)及李+半枫荷(Semiliquidambar cathayensis)+地枫皮(Illicium difengpi)为研究对象，比较不同林药复合生态系统在除砂和含砂处理下土壤团聚体组成、稳定性及可蚀性特征，并分析土壤团聚体稳定性综合得分与土壤可蚀性之间的关系。[结果]①无论除砂与否，林药复合生态系统可促进微团聚体(＜0。053 mm)向大团聚体(＞2mm)的转化。②林药复合生态系统，特别是李+金丝桃系统，整体上提高了土壤团聚体平均质量直径、几何平均直径、＞0。25 mm水稳性团聚体含量，但却降低了分形维数和可蚀性因子。同时，土壤团聚体稳定性综合得分与土壤可蚀性之间呈显著负相关。③相比于除砂处理，含砂在一定程度上高估了各系统土壤结构特征参数。[结论]林药复合生态系统，尤其是李+金丝桃系统，对土壤团聚体稳定性和可蚀性具有积极的改善作用，但系统构建过程中应该注意植物物种数量和配置的互补性以达到最优组合。需要准确评价土壤结构功能，以便对喀斯特区土壤含砂量进行合理校正。
Stability and Erodibility of Aggregate Affected by Typical Tree-herb Ecosystems in Karst Area
[Objective]The aim was to explore short-term effects of tree-herb ecosystems on soil aggregate characteristics,in order to provide a theoretical basis for a comprehensive assessment of the ecological and economic effects of vegetation restoration transitions in karst regions.[Methods]Four tree-herb ecosystems based on Prunus salicina were selected,including Prunus salicina+Rubus chingii,P.salicina+Polygala fallax,P.salicina+Hypericum monogynum,and P.salicina+Semiliquidambar cathayensis+Illicium difengpi.Monocultures of P.salicina were used as controls.These ecosystems were compared in terms of soil aggregate composition,stability,erodibility,and their relationship under sand removal and sand inclusion treatments.[Results]① Tree-herb ecosystems facilitated the conversion of microaggregates(＜0.053 mm)into macroaggregates(＞2 mm),irrespective of sand extraction.② Tree-herb ecosystems,particularly the P.salicina+H.monogynum system,increased the mean weight diameter,geometric mean diameter,and content of water stable aggregates＞0.25 mm within soil aggregates,but decreased the fractal dimension and erodibility factor.Meanwhile,a significant negative correlation was found between the comprehensive score of soil aggregate stability and erodibility.③ The presence of sand led to a slight overestimation of the soil structure characteristic parameters in each ecosystem compared with the treatment involving removal of sand.[Conclusion]Tree-herb ecosystems,especially P.salicina+H.monogynum system,have a positive effect on soil aggregate stability and erodibility,but the number of plant species and the complementarity of the configuration and an optimal combination should be considered in constructing ecosystems.Meanwhile,future studies should accurately assess the soil structure function in order to correct the soil sand content in karst regions.
Aggregate distributionErodibilityTree-herb ecosystemKarst areaLijiang River basin
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