西藏米拉山高寒草甸土壤水分的空间异质性

Spatial Heterogeneity of Soil Moisture in Alpine Meadow of Mila Mountain,Tibet

土壤水分可以直接影响土壤特性以及植物的生长过程,是影响西藏高寒草甸区植被类型及分布和人工促进植被恢复的重要因子,对于研究高寒区的植被恢复,荒漠化分类等具有重要实践意义。本文运用地统计学与GIS相结合的方法,以米拉山高寒草甸地带为研究对象,研究其土壤水分的空间异质性。结果表明:1)研究区不同深度土壤含水量的平均值介于23.14%~35.52%,总体上表现为土壤含水量较高。样地的不同土层土壤含水量均表现为中等变异性。2)从地统计分析的结果看,两个样地的土壤含水量具有较强的空间相关性。不同样地不同土层的变程反映出,本研究中最小的取样间距是合理的。3)空间插值分析,可以从总体上反映出样地内不同样点的土壤含水量的空间分布格局。4)相关性分析,表明各土层的土壤含水量具有极显著的相关性(p<0.01)。该研究中两个样地分别位于米拉山山顶两侧,其坡向、坡度、植被类型及植被覆盖情况有很大的差异,进一步导致了两个样地的土壤水分空间异质性差异。

Soil moisture could affect soil properties and the growth process of plants directly,which was an important factor affecting the types and distribution of vegetation in Tibet's alpine meadow area and artificially promoting vegetation restoration.The purpose of this study was to characterize the distribution of soil moisture on alpine meadow land types.Taking two sample plots in alpine meadow of Mila Mountain as a case study,geo-statistical and GIS methods were conducted to examine the spatial variability and vertical characteristics of soil moisture.The results showed that the mean soil moisture content at different depths on alpine meadow land was from23.14%to 35.52%.In general,the soil moisture content was relatively high.,and the soil water content of different soil layers in the sample plots all showed moderate variability.From the results of geo-statistical analysis,it was concluded that the soil moisture content of the two plots had a strong spatial correlation.The variable range reflected that the smallest sampling interval in this study was reasonable.The spatial interpolation analysis generally reflected the spatial distribution pattern of soil moisture.The correlation analysis showed that the soil moisture content of each soil layer had a very significant correlation(P<0.01).In this study,the slope aspect,slope,vegetation type and vegetation coverage of the two sample plots were quite different,which further led to the difference in the spatial heterogeneity of soil moisture between the two plots.