不同人工造林树种及其配置方式对土壤理化性质影响分析

人工造林是黄土高原改善生态环境,减少水土流失的重要手段。不同树种及其配置方式下地表植被的生长、土壤理化性质的差异影响着生态水文功能的强弱。以长武王东沟流域8种造林树种和不同配置径流小区为研究对象,采用样方法进行造林地及林下地表植被调查,分层采样测定0—40cm土层土壤容重、孔隙度、有机质含量,分析不同人工造林模式下土壤理化性质,并初步分析了植被特征与土壤理化性质间的关系。结果表明:不同造林方式小区内林下草本层虽然覆盖度区别很大,但物种丰富度、多样性、均匀度指数差异不显著。0—20cm表层土壤理化性质变异性小于20—40cm土层。不同人工造林方式间土壤容重差异显著,且对20—40cm层土壤的毛管孔隙度、总孔隙度有显著性影响。不同造林方式下草本层丰富度、多样性指数与林下土壤毛管孔隙度相关性显著。草本层丰富度、多样性与0—20cm表层土壤的保水作用存在良好的对应关系。相比较而言,0—40cm土壤剖面上,草地和侧柏刺槐混交林地下的土壤孔隙度和有机质等理化性质,以及相关的蓄水性和入渗性等生态水文功能要好于其他造林林种。

Impacts of Vegetation Types on Soil Physicochemical Properties

The ecological environment in Loess Plateau is fragile and the soil erosion is sever.Afforestation is the important means to improve the ecological environment.Different plantation species and configuration modes affect physicochemical properties of soil and soil erosion.Eight runoff plots with various afforestation species and different configurations in Wangdonggou watershed located in Changwu were selected in this research,and quadrat method was used in understory vegetation ecological investigation.Soil bulk density,porosity,organic matter content in soil layer were measured;physicochemical properties were also analyzed under different artificial afforestation models.The results showed that the richness,diversity and evenness index of herb layer under different types of understory vegetation showed non-significant difference,and physical and chemical property difference in 20-40 cm soil layer was greater than that in the surface layer.The soil bulk densities in plots with various plantations were significantly different,and the vegetation cover had the significant effect on soil capillary porosity and total porosity in 20-40 cm layer.The capillary porosity had a markedly relation with the richness,diversity index of herb layer,so did total porosity and organic matter.In the 0-40 cm soil profile,grasses have a good ability to increase the water storage and infiltration.Herbaceous species richness and species diversity indices were passtively correlated with water storage in topsoil.