华北土石山区优先流区与基质流区土壤特性分析

Soil characteristics of preferential flow area and matrix flow area in Rocky Mountain Area of Northern China

在非饱和土壤中,优先流是一种较为常见的现象。针对华北方土石山区的优先流现象,在鹫峰森林公园选取6块样地,利用染色示踪法获取优先流路径,分析林地优先流区和基质流区土壤孔隙度与水分变化的差异,以及土壤初始含水率对优先流(最大染色深度、50%染色深度、染色比例)的影响。结果表明:1)土壤中优先流区非毛管孔隙度和总孔隙度比基质流区的大,毛管孔隙度在优先流区与基质流区无明显差异;2)试验后优先流区土壤含水率变少,含水率减少平均比例是21%,基质流区试验前后含水率几乎无变化,含水率变化比例是0;3)初始含水率与染色比例呈正相关(R2=0.679),与50%染色深度呈正相关(R2=0.527),与最大染色深度相关性小(R2=0.236)。

Preferential flow is a major infiltration process in unsaturated soils. We conducted a dyestaining experiment in Beijing Jiufeng National Forest Park,in order to analyze the differences of soil porosity and soil moisture in preferential flow area and matrix flow area,as well as the effect of antecedent soil moisture（ ASM） on preferential flow characteristics（ i. e.,maximum dyed soil depth,50% dyed soil depth,dyed soil percentage）. Results indicated that： 1） the non-capillary porosity and the total porosity of the soil in preferential flow area were statistically higher than those in the matrix area,and no statistical difference in capillary porosity was found between the two areas; 2） soil moisture in the preferential flow area decreased by 21% after the experiment,while there was no difference in soil moisture in the matrix flow area; 3） ASM was positively correlated with the dyed soil percentage（ R2=0. 679） and 50% dyed soil depth（ R2= 0. 527）; in contrast,no apparent correlations were found between ASM and the maximum dyed soil depth（ R2= 0. 236）.