河北坝上地区坡面尺度根系生物量空间变异

坝上草原的水土保持对于京津的生态环境有着重要的作用，而根系生物量随水平、海拔、深度等方向的空间变异对于水土保持有重要影响。采用根钻法实地采样，通过ArcGIS空间插值方法，构建完整坡面根系生物量各深层分布图，探究随不同凹凸坡形及其过渡带根系生物量分布特征的变化。通过SPSS指数回归分析，探究根系生物量随深度的变化。结果表明，水平方向上，根系生物量的极值多分布于区域的边缘，其中凸坡和凹坡极大值出现最多，中下坡根系生物量相对较多。深度方向上，根系生物量密度随深度呈指数函数变化的特征，其中含有钙积层的偏凸坡位置根系生物量随深度减少较快、含有沟壑的偏凹坡位置根系生物量减少较慢。因此，微地形是在坡面尺度上影响根系生物量空间分布的主导因素。

Spatial Variability of Root Biomass at Slope Scale in Bashang Region of Hebei Province

Bashang area in Hebei Province is a vital region with the function of protecting the ecological environment of Beijing and Tianjin. Root density distribution characteristics, whether horizontal, vertical, or depth, are important factors on preventing erosion in this area. The objective of the research is to produce a model of the slope that reflects these characteristics, continuing to develop the research on the relationship between root weight distribution and different slope shapes, i.e concave, sub-concave, sub-convex and convex. Using the samples collected by a root drill, the raster interpolation function of ArcGIS was utilized to produce a model in layers of 2D images. Besides, the exponent regression function of the program SPSS was utilized to analyze the root distribution in the vertical direction. The results show that, for horizontal layers, the majority of the root is on the edge of the slope, especially in the concave and the convex positions. The foot of the slope is also place where the roots congregate. As for the depth data, the root weight decreases following the exponential rate which shows the high capacity of concave area including gutter area and low capacity of convex area including calcic horizon to keep the moisture. Topography is an essential factor on root biomass distribution at slope scale.