黄土塬区不同地形部位和土地利用方式对土壤物理性质的影响

在黄土塬区王东沟流域采集不同地形部位和不同土地利用方式下土壤样品，测定其颗粒组成、容重和饱和导水率，借助变异系数、非参数检验等方法研究了不同地形部位和不同利用方式对土壤物理性质的影响.结果表明：土壤物理性质在水平方向和沿垂直剖面都存在变异，但在同一地形部位或同一土地利用类型内，容重和颗粒组成基本相似.水平方向，饱和导水率属强变异，粘粒和砂粒含量属中等变异，粉粒含量和容重属弱变异；沿垂直剖面，土壤的粒级分布具有连续性，但0～25 cm的土壤容重和饱和导水率与下层土壤差异显著.沿坡面从上向下，土壤趋向粘重，但饱和导水率增大；其中上坡位和中坡位的土壤性质相似，在相关研究中可以进行合并.草地与其他利用方式下的土壤性质差异显著，主要受地形部位的影响；耕地和果园的土壤性质相似且不同于其他利用类型，表明人为干扰对土壤物理性质有重要影响.

Effects of land use type and slope position on soil physical properties in loess tableland area.

Soil samples under different land use types and at different slope positions in the Wangdonggou watershed of loess tableland area were collected to determine their particle composition, bulk density (pb), and saturated hydraulic conductivity (Ks), and the effects of land use type and slope position on the soil physical properties were studied in virtue of the variation coefficient and non-parameter tests. The results showed that the physical properties of soil varied in horizontal direction and vertical profile, however at the same slope position or under the same land use type, the pb and particle composition were similar. In horizontal direction, Ks varied strongly, slit content and pb varied weakly, and clay and sand contents varied medially. In vertical profile, soil particles had a continuous distribution, but pb and Ks varied greatly in 0-25 cm layer. With the slope degree descended, soil contained more clay and had a higher pb, and Ks increased. At upper and middle slopes, soil physical properties were similar, and thus, could be merged into one in related researches. There was a significant difference in soil physical properties between grassland and other land use types, which was mainly due to the effects of slope position, but the soil physical properties in farmland and orchard were similar, indicating the important effects of human activities.