甘肃灌漠土土壤肥力的空间变异性典型研究

Spatial Variability of Irrigated Desert Soil Fertility in Gansu Province

结合传统统计与地统计学方法对甘肃省河西地区武威灌漠土土壤肥力的空间变异性进行了分析。描述性统计结果显示,该地土壤肥力具有较大的空间变异,土壤NH+4 N的变异系数最高,为62 656%,速效磷的变异系数次之,为47 369%,pH的变异系数最小,仅为1 284%,有机质和速效钾的变异系数分别为13 208%和38 075%。地统计学分析表明该区域土壤特性的块金方差/基台值比值[C0/(C0+C)]在0 0413%～13 7801%之间,说明该土壤性质的各项指标均有强烈的空间相关性,其中NH+4 N和pH值的空间相关性相对最强,[C0/(C0+C)]分别为0 0413%和0 0978%;速效磷相对最弱,[C0/(C0+C)]为13 7801%;有机质与速效钾居中。土壤肥力性质的相关距变化范围为176～294m。该土壤性质的克立格插值结果显示出一定的空间相似性,显示地统计学方法可用于分析土壤肥力在空间上的变异。

The spatial variability of irrigated desert soil nutrients has been analyzed for Hexi region in Gansu province by using mathematical statistics and geo-statistics methods. The results from mathematical statistics showed that the spatial variability of the tested soil nutrients was sharp; the variance coefficient of available NH^+_4-N was the highest(62\^656%), that of pH was the lowest(1\^284%), that of Phosphorous(P) was the second(47\^369%), and that of organic matter(OM) and available potassium(K) were 13\^208% and 38\^075% respectively. The results from geo-statistics analysis revealed that the nugget-sill ratios of all indices of soil nutrients varied from 0.041 3% to 13.780 1% and they showed that there were strong spatial dependences for soil NH^+_4-N, available P, available K, OM and pH. Among the tested soil nutrients the spatial dependences of NH^+_4-N and pH were the strongest and their nugget-sill ratios were (0\^041 3%) and (0\^097 8%), and the spatial dependence of the available P is weakest and the nugget-sill ratio was (13\^780 1%). The effective range of soil fertilities varied from 176 to 294 meters. The results of Kriging showed that to some extend soil nutrients had spatial dependence and geo-statistics method could be used to analyze the spatial variability of soil nutrients.