鄂西南亚热带常绿落叶阔叶混交林不同群落类型土壤特征分析

研究不同群落类型的土壤特征是了解植被-环境关系的基础,也是对生态系统进行科学管理的重要依据。论文以鄂西南两个自然保护区内亚热带常绿落叶阔叶混交林5个不同类型群落的土壤为对象,在测定10个理化指标的基础上,对不同群落类型的土壤特征及其差异性与相关性进行分析。结果表明：土壤含水量、孔隙度、全磷是影响鄂西南亚热带常绿落叶阔叶混交林土壤特征变异的主导因子。研究区土壤除了全磷和有效磷不足以外,其余养分含量均处于较高水平,和亚热带其他类型森林相比养分十分丰富。不同群落类型下土壤理化性质及其相关性均存在差异,与群落的组成和结构存在紧密的联系。

Soil Characteristics under Different Community Types in the Subtropical Evergreen and Deciduous Broad-leaved Mixed Forest in Southwest Hubei

As an essential substrate for plant growth, soils under vegetation play important roles in regulating the composition and structure of plant communities, which inversely have great influences on the properties of soils. The evergreen and deciduous broad-leaved mixed forest is the most important vegetation type in subtropical mountain of southwest Hubei. It plays an irreplaceable role in maintaining the regional eco-environmental health. However, we know little about the features of the soil under this forest. In this paper, the characteristics of soils under five community types in the subtropical evergreen and deciduous broad-leaved mixed forest in southwest Hubei were analyzed. Based on measurements of 10 physical-chemical properties of soil samples from 92 permanent forest plots of five plant communities, we compared the characteristics and their variations among the soils under the five communities. Correlations among different soil factors under different communities were tested. The dominant factors and the overall qualities of soils under different communities were identified and assessed by using Principal Component Analysis. The result showed that: 1) The soil pH, organic matter, total nitrogen, total phosphorus, available nitrogen, available phosphorus under different communities varied significantly. 2) The dominant factors for determining the overall properties of soils across the subtropical evergreen and deciduous broad-leaved mixed forest in southwest Hubei were soil total nitrogen, soil moisture and soil total porosity. 3) The top three dominant factors for determining the overall properties of soils under each of the five communities ranked as follows: soil moisture, total porosity and density under community Ⅰ (Cyclobalanopsis glauca - Eurya alata + Camellia cuspidata); soil available kalium, total phosphorus and moisture under community Ⅱ(Carpinus fargesiana + Cyclobalanopsis glauca - Symplocos sumuntia); soil total porosity, pH and moisture under community Ⅲ(Carpinus fargesiana + Cyclobalanopsis glauca - Weigela japonica); soil total porosity, moisture and available kalium under community Ⅳ(Fagus lucida + Cyclobalanopsis multinervis-Eurya alata); and soil organic matter, total phosphorus and nitrogen under community Ⅴ(Carpinus fargesiana + Daphniphyllum macropodum + Lithocarpus cleistocarpus - Eurya alata). 4) The comprehensive quality for soils under the five communities ranked as: community Ⅰ> community Ⅲ> community Ⅳ> community Ⅱ> community Ⅴ. Our results indicated that soil nutrients content were higher under subtropical evergreen and deciduous broad-leaved mixed forest in southwest Hubei, except the soil total phosphorus and available phosphorus. The variation of soils among different communities might be caused by the composition and structure of the communities. More researches remain to be done on the mechanism of the circulation of materials and the mutual effect between soil and vegetation.