典型喀斯特森林土壤的抗蚀性

喀斯特地区生态脆弱,极易发生土壤侵蚀。受地表要素空间异质性的影响,目前相关研究仍无法完全反映出喀斯特地区不同植被类型土壤抗蚀性的特征。通过野外调查,了解样地植被群落类型及其组成等基本情况,并以"S形布点法"实地采样;通过酒精烘烤法、环刀法等方法,获取土壤含水量、土壤容重、土壤有机质、土壤团聚体、土壤微团聚体及土壤机械组成、土壤抗蚀指数等土壤抗蚀指标值。结果表明,除有机质外的其他抗蚀指标表现出0—10cm土层内与10—20cm土层内的变化规律均和抗蚀指数一致。在土壤深度0—10cm范围内,土壤抗蚀指数表征的土壤抗蚀能力强弱为:阔叶林灌丛针叶林;在10—20cm土层范围为:灌丛针叶林阔叶林。0—10cm土层内各指标表征土壤抗蚀能力的显著程度为:有机质含量、水稳性团聚体、结构破坏率、团聚状况和团聚度较显著,10—20cm土层内为有机质含量、干筛团聚体、团聚度较为显著,水稳性团聚体次之。通过综合两个土层的情况,可认为有机质含量、水稳性团聚体、团聚度能较好地表征喀斯特林地土壤抗蚀性强弱。在喀斯特地区如果以防治土壤侵蚀为目的,应考虑种植阔叶树种,避免针叶树种。

Study on soil anti-erodibility of typical karst forests

The karst region is ecologically fragile and is highly prone to soil erosion. Affected by the spatial heterogeneity of surface elements, previous researches can not fully reflect the characteristics of soil erosion resistance of different vegetation types in karst area. Through field investigation, we obtained the basic conditions of the vegetation community types and their composition. And the S-shaped layout method is used for field sampling. The soil anti-erodibility indices were obtained by the alcohol baking method, ring knife method and other methods, including soil water content, soil bulk density, soil organic matter, soil aggregates, soil microaggregates, soil mechanical composition and soil erosion resistance index. Results indicated that soil anti-erodibility indices other than organic matter content reflected the same variation law in 0-10cm soil layer and 10-20cm soil layer, they were consistent with the soil erosion resistance index. In the soil depth of 0-10cm, the soil anti-erodibility characterized by soil erosion resistance index follows the order:broad-leaved forest > bushwood > coniferous forest. In 10-20cm soil layer, the soil anti-erodibility is ranked in order of bushwood > coniferous forest > broad-leaved forest. The indicators that can significantly characterize soil anti-erodibility in 10-20cm are:organic matter content, water-stable agglomerate, structural failure rate, agglomeration condition, and agglomeration degree. While in 10-20cm soil layer, they are organic matter content, dry sieve agglomerate, agglomeration degree, and water-stable agglomerate. By comprehensive analysis of the two soil layers, organic matter content, water-stable agglomerates, and agglomeration degree can better characterize the anti-erodibility of soil in karst forest land. For the purpose of controlling soil erosion, broad-leaved tree species instead of conifer species should be considered in the karst area.