Spatial Heterogeneity of Surface Soil Particles of Patch Vegetation in Desert-Oasis Ecotone

In this paper,we regard the typical plot as study area.The plot is located in desert-oasis ecotone of Hexi Corridor in Gansu Province.The methods of soil sieve analysis and geo-statistics are applied to analyze the composition characteristics and spatial heterogeneity of surface soil particles of patch vegetation in the study area.The analysis results reveal that:(1)The quality percentage of surface soil particle has significant difference in different soil particle size range,the particle size of soil particles is mainly in the range of 0.25-0.075mm in the area,the particle size range of soil particles is considered fine sands,and accounts for 75.1359% of total soil particle quality.Followed by medium sands,its particle size is in the range of 0.5-0.25mm,and accounts for 13.2730% of the total. The coarse sands(d0.5mm)and silty sands(d0.075mm)take up a smaller proportion respectively,and only occupy 5.1895% and 6.4016%of the total.(2)The soil particle of different particle size range has the significant spatial heterogeneity,for the soil particle size is in the range of 1-0.1mm,and the autocorrelated spatial heterogeneity is a main component of the spatial heterogeneity with the percentage of nugget(C0)/sill(C0 +C)varying from 0.4% to 11.2%,that is,the spatial heterogeneity is primarily caused by the spatial autocorrelation factors which accounting for 99.6%~88.8% of the degree of spatial heterogeneity.But for the soil particles of other particle size range,the random variance of spatial heterogeneity is a main component with the percentage of nugget(C0)/sill(C0 +C)varying from 95.1% to100%.(3)The soil particles of particle size are in the range of 1-0. 1mm,the curve model is considered as the best fitting theory model,and their spatial heterogeneity scale is relatively small,varying from 24m to 36.3m,but the soil particles of other particle size range fit to linear models and nugget model with large-scale spatial heterogeneity,and their spatial variability scale reaches to 146.36m.This research results will provide scientific reference for further study in the connection between the soil spatial heterogeneity and the vegetation spatial pattern.