黄土区坡面尺度不同植被类型下土壤干层的空间分布

Spatial distribution of dried soil layers under different vegetation types at slope scale in loess region

为掌握坡面尺度不同植被类型土壤干层特征,对一典型坡面干层空间分布进行了研究。结果表明:13a杏树地和25a柠条地干层厚度分别在0～400和280～400cm之间,杏树地不同坡位处干层分布有明显差异;在坡面垂直方向上,25a柠条地较13a杏树地土壤水分亏缺严重。而水平方向,13a杏树地干层分布表现为明显的片状和斑块状分布特征,同时呈现出从北至南沿坡面逐渐递减,干层分布受植被,降水、坡位、微地形等因素共同作用。相比之下,25a柠条地干层分布结构性较为单一,干层厚度在381～400cm的面积分布较广且连在一起,表现出由植被控制的分布格局。相关结果可为黄土区土壤干层调控提供参考。

To understand the characteristics of dried soil layer（DSL） under different vegetation types at slope,the spatial distribution patterns of DSL on a representative slope were studied.The results showed that the extent of DSLs ranged from 0 to 400 cm for orchard（13 years of Prunus armeniaca） and from 280 to 400 cm for shrubland（25 years of Caragana Korshinskii kom）,respectively,while slope position significantly influenced distribution pattern of DSLs in the orchard.In vertical direction,the depletion of soil water was more severe in shrubland than that in orchard.Horizontally,distribution of orchard DSL demonstrated obvious fleck and sheet characteristics and decreased gradually along north-south direction of the slope.Spatial pattern of DSLs in the orchard was controlled by vegetation,rainfall,slope gradient and micro-terrain.In contrast,the distribution pattern of DSL in shrubland was homogeneous that deeper DSLs（381～400 cm） distributed widely and combined together,implying that this pattern was only dominated by vegetation type.The results are helpful for DSL control and/or reclaim in loess regions.