毛乌素沙地不同林龄沙柳表层土壤水分空间异质性

利用经典统计学与地统计学相结合的方法对毛乌素沙地不同林龄沙柳表层土壤（0-20 cm）水分空间异质性进行研究。结果表明,随着林龄的增长,表层土壤水分含量有增加的趋势,增加幅度为5.46%-6.60%;不同林龄沙柳表层土壤之间水分含量差异极显著（p〈0.01）。变异函数分析显示,2-4年的沙柳林中,随着林龄的增长,使得基台值和空间结构比增大,沙柳表层土壤水分含量具有高度的空间异质性,其空间异质性以空间自相关部分为主,从占总空间异质性的63%增大到87%;各向异性分析也表明,在空间上不同林龄表层土壤水分具有明显的各向异性;其空间格局有明显的差异,2年生沙柳林表层土壤水分含量的分数维较低,4年生沙柳林的分数维最大,斑块形状复杂程度增大,表层土壤水分空间分布趋于离散。

Spatial Heterogeneity of Top Soil Moisture in Different Stand Age of Salix psammophila in MU US Sandy Land

The spatial variability of soil moisture is remarkable.Here we used traditional statistics and semivariance analysis of geostatistics to test for differences in the spatial heterogeneity of top soil(0~20 cm) moisture of three different stand age of Salix psammophila in the MU US sandy land.The results showed that there is a tendency towards increasing of the topsoil moisture with the growth of Salix psammophila stand age;the increase range is 5.46% to 6.60%.And all the sampling date of different stand age of Salix psammophila had a significantly(p<0.01) effect on top soil moisture.Semivariogram analysis demonstrated that there is a high spatial heterogeneity in soil moisture.The means of nugget,sill and structural ratio(C/C_0 C) increased with the growth of Salix psammophila stand age.Spatial heterogeneity in top soil moisture was mainly caused by spatial autocorrelation,63% to 87% with the growth of Salix psammophila stand age.There are high levels of variation in pattern in the different stand age of Salix psammophila.The spatial patchiness for top soil(0~20 cm) moisture of 4 years old Salix psammophila is the most fragmented.Because of the increase of spatial heterogeneity,the tendency of top soil moisture is dispersed.