黄土区不同植被类型条件下土壤分离速率变化特征及其影响因素

为比较土壤理化性质与根系特征对土壤分离速率的影响强度，采用模拟冲刷试验与室内分析相结合的方法，探究了黄土区不同植被类型在3种处理下（含根系、含冠层、含结皮）土壤分离速率变化特征及其影响因素。结果显示:（1）不同植被类型间，狼牙刺群落下土壤分离速率最小，显著低于达乌里胡枝子；不同处理下，含结皮土壤分离速率最大，含根系土壤次之，含冠层土壤最小。（2）土壤分离速率与容重呈显著正相关关系（p<0.05），与有机质、团聚体呈显著负相关关系（p<0.05）。只考虑土壤理化性质对土壤分离速率的影响时，影响狼牙刺、白羊草群落下土壤分离速率的主导因素是容重；影响铁杆蒿、达乌里胡枝子群落下土壤分离速率的主导因素为有机质。（3）根系特征也是影响土壤分离速率的因素，土壤分离速率与根系生物量密度、根长密度、根系表面积密度、根体积密度呈负相关关系。只考虑根系特征对土壤分离速率的影响时，影响狼牙刺、铁杆蒿、白羊草群落下土壤分离速率的主导因素是根长密度；影响达乌里胡枝子群落下土壤分离速率的主导因素是根系表面积密度。（4）本研究中，土壤分离速率回归方程D_r=0.086-0.035X₁+1.367X₂，（R²=0.767，N=36，p=0.000；X₁为土壤有机质，X₂为土壤容重），土壤理化性质对于分离速率的作用强于根系的作用；不考虑植被类型时，土壤有机质、土壤容重是影响土壤分离速率的主导因素。

Changes and Influences of Soil Detachment Rate Under Different Vegetation Types in the Loess Plateau

In order to compare the effects of soil physical and chemical properties and root characteristics on soil detachment rate, using the method of erosion simulation test and laboratory analysis, we examined the changes and influences of soil detachment rate under different vegetation types in 3 kinds of treatments (root, canopy, and crust) in the Loess Plateau. The results showed that:(1) between different vegetation types, the soil detachment rate of Sophora viciifolia community was the lowest, significantly lower than Lespedeza davurica community; under different treatments, the detachment rate of crustal soil was the largest, followed by root soil, and then canopy soil; (2) the soil detachment rate was significantly positively related to soil bulk density (p < 0.05), the soil detachment rate was significantly negatively related to soil organic matter, soil aggregate (p < 0.05); If the influence of physical and chemical properties of soil on the soil detachment rate was only considered, the dominant factor influencing the soil detachment rate of S. viciifolia community and Bothriochloa ischaemum community was soil bulk density; the dominant factor influencing the soil detachment rate of Artemisia gmelinii community and L. davurica community was soil organic matter; (3) root characteristics were also the factors that influence the soil detachment rate; the soil detachment rate was negatively related to root biomass density, root length density, root surface area density and root volume density; If the influence of root characteristics on the soil detachment rate was only considered, the dominant factor influencing the soil detachment rate of S. viciifolia community, A. gmelinii community and B. ischaemum community was the root length density, the dominant factor influencing the soil detachment rate of L. davurica community was the root system surface area density; (4) in this study, the regression equation of soil detachment rate was expressed as D_r=0.086-0.035X₁+1.367X₂, (R²=0.767, N=36, p=0.000, X₁ is soil organic matter, X₂ is soil bulk density); the influence of physical and chemical properties of soil on the detachment rate was stronger than that of the root system; without considering the vegetation types, soil organic matter and soil bulk density were the key factors to decrease the soil detachment rate.