青藏高原高寒草甸区土壤水分的空间异质性

通过网格(10m×10m)取样,用地统计学方法研究了青藏高原高寒草甸覆盖区域(110m×90m)浅层剖面(0~40cm)土壤水分的空间异质性特征。结果表明:在高寒草甸覆盖区0~30cm深度范围内,土壤水分均存在高度空间异质性,其中87.3%~74.9%的空间异质性是由空间自相关部分引起的,主要体现在201m以下尺度,10m以下随机因素对空间异质性作用较小;30~40cm土壤水分空间异质性由10m以下尺度随机因素导致的占42.3%,而自相关部分的空间异质性(57.7%)体现在10~87.2m尺度。随土层深度的增加,分维数D有逐渐增大的趋势,说明随深度增加高寒草甸区土壤水分自相关空间异质性程度在降低,而随机因素导致的空间异质性程度在增加。从4层的C₀/(C+C₀)值来看,10~20cm这一层的值最小,表明在这一层的系统变量的空间自相关性程度最高。说明高寒草甸区0~30cm土层的土壤水分含量是受降水、植被发育、根系分布、土壤特性和人为干扰等影响,其空间异质性主要受自相关因素控制,而30cm以下的土壤水分受自相关因素和随机因素共同控制。

Spatial heterogeneity of soil moisture in alpine meadow area of the Qinghai-Xizang Plateau

In this paper geo-statistical theory and methods are used to study the spatial heterogeneity of loll moisture characteristics in shallow profile (0~40 cm) of alpine meadow areas(110 m×90 m) in the Qinghai-Xizang Plateau.The 352 sampling points are fixed in total Using the grid sampling method(10 m×10 m space).The results show that in alpine meadows 0-30 cm depth of coverage area,there is a high degree of spatial heterogeneity of soil moisture.Within 87.3%-74.9% spatial heterogeneity,part of the spatial autocorrelation is at 0-30 cm depth.The auto-correlation factors at 10-201 m scale play an important role in the 0-30 cm soil moisture spatial heterogeneity.But spatial heterogeneity of mil moisture at the layer of 30-40 cm depth can be controlled by the random and auto-correlation factors.With the increase of depth the fractal dimension D has a gradually increasing trend.The warthy noting is that the random factor will increase at soil depth for soil moisture spatial heterogeneity.From the C₀/(C+C₀) comparable values of soil four layers,the minimum value is in the lowest level of thi s 10-20 cm,the level of system variables is shown in the highest degree of spatial autocorrelation.mil moisture content of the layer 0-30 cm of alpine meadows area is affected by precipitation,vegetation growth,mot distribution,soil characteristics and impacts of human interference et al.