甘肃省武威地区灌漠土微量元素的空间变异特征

用经典统计学与地统计学方法相结合,研究了甘肃省武威灌漠土耕层土样中B、Cu、Fe、Mn及Zn等5种微量元素有效含量的空间变异特征。结果表明:①99.17%土样缺乏有效Zn,93.33%的土样缺乏有效Fe。描述性统计所得变异系数在13.32%(有效Mn)~42.54%(有效B)之间。②球状模型和指数模型为土壤微量元素的最佳拟合模型,各元素的块金值、最大相关距及块金值与基台值之比C0/(C0+C)分别在0.001~0.429、192m~477m及0.126%~26.459%(有效B)之间。土壤微量元素含量的分形维数在1.804~1.947之间,土壤B的分形维数最低。③表征土壤微量元素空间变异的参数如变异系数、C0/(C0+C)及分形维数D之间均有一定的相关关系。④Kriging插值结果显示人为因素等表生作用对土壤有效B含量的空间分布影响较大,土壤Cu、Mn、Zn及Fe含量的空间分布则主要由成土母质与地形所决定。

Spatial Variability of Micronutrients of Irrigated Desert Soil in the Baiyun Village of Wuwei Rgion

With the methods of mathematical statistics and geo-statistics, we analysized the spatial variability of soil micronutrients such as B, Cu, Fe, Mn and Zn in irrigated desert soil of Wuwei, Gansu province. The results showed that 99.17% of the samples was short of available Zn and 93.33% of them lacked of available Fe. The CVs from mathemtical statistics were between 13.32% (available Mn) and 42.54% (available B). The spheric model and exponential model were the optimal models that showed the spatial variability of micronutrients. The nuggets, ranges and the ratios of C_0 and C_0 C of all tested micronutrient contents were between 0.001 and 0.429, 192m and 477m, and 0.126% and 26.459% (available B), respectively. The fractal dimensions that revealed the soil micronutrients' spatial variability varied from 1.804 to 1.947 and the fractal dimension of available B content was the lowest. There were relationships among CVs, the ratioes of C_0 and (C_0 C) and fractal dimensions. Using the maps of the soil trace elements with Kriging to show the effects of human's action on the trace elements' spatial variability, the results showed that there were strong effects of human's action on the spatial variability of available B. The spatial distributions of the contents of Cu, Mn, Zn, and Fe were decided by the soil material and the topography in Wuwei irrigated desert soil.