关中东部不同土地利用方式对土壤质地影响探讨

以陕西关中渭北作为研究区，选取典型农业耕地和人工苹果林地，分析出这两种土地利用方式对土壤粒度分布的影响。结果表明：①研究区土壤主要由粉砂和黏粒组成，占总含量的80％以上，总体属于粉砂质黏壤土；②不同土地利用方式土壤砂（〉50μm）、粉砂（2μm～50μm）和黏粒（〈2μm）含量差异显著。耕作土壤2v～50μm含量明显低于人工苹果林地，而〈2μm和〉50μm含量却高于苹果林地；③不同土地利用方式土壤粒度分布的变异系数不同。耕作土壤粒度分布的变异系数整体小于苹果林地土壤。耕作土壤，〈2μm和〉50μm的的变异系数在上层较高，2μm-50μm的变异系数在整个剖面变化不大。苹果林地土壤，〈2μm的变异系数在上层较低，〉50μm变异系数的变化与〈2μm相反，2μm～50μm的变异系数在整个剖面变化不大。究其原因，人类活动如不同的耕作或管理方式以及种植作物类型可能是影响土壤粒度分布的主要因素。图1，表2，参10。

Effect of Land Use on the Soil Texture in East Guanzhong of Shaanxi Province, North China

Taking northern Weinan of Guanzhong as a study case, we investigated the effect of land use on distribution of grain size of cultivated soil and anthropogenic forest soil. The results are as follows： （1）the soils mainly compose of clay and silt, and amount of clay and silt particles is more than 80 percent; （2）different land use patterns affect the distribution of sand, clay and silt significantly. The amount of cultivated soil is less than anthropogenic forest soil in 2μm - 50μm grain-size, but it is reverse in 〈 2μm and 〉 50μm grain-size; （3）different land use patterns affect coefficient of variation. Coefficient of variation of cultivated soil is less than that of anthropogenic forest soil . Coefficient of variation of the upper layer on the cultivated soil in 〈 2μm and 〉 50μm grain-size is high, but the lower layer is low, it is unobvious in 2μm - 50μm grainsize. Coefficient of variation of the upper layer on the anthropogenic forest soil in 〈 2μm is low, There are reverse in 〉 50μm grain - size and in 〈 2μm grain-size,but it is unobvious 2μm- 50μm grain-size. Human activities such as cultivation and management ways crop species are probably the main factors for distribution of grain size.