黑土质量演变初探Ⅳ——吉林省公主岭地区土壤肥力指标空间变异与评价

An Approach to the Changes of Black Soil Quality(Ⅳ)——Spatial Variability of Soil Fertility Indices in Gongzhuling

采用地理信息系统(GIS)和地统计学相结合的方法研究了吉林省公主岭地区土壤表层(0￣20cm)pH、有机质、速效磷、速效钾、粘粒这5种土壤肥力指标的空间变异性。结果表明:土壤pH、有机质、速效钾、粘粒的理论模型均为球状模型;速效磷的理论模型为纯块金效应模型。粘粒、速效钾、有机质、pH的C0/(C0+C)变化范围是37.27%～49.66%,均表现出中等的空间相关性,说明其空间变异是由随机性因素和结构性因素共同作用的结果。根据目前的评价标准,该地区土壤pH和有机质主要分布在2～3级;速效磷和速效钾主要分布在2～4级;而粘粒则分布在3～4级,说明该地区肥力指标基本上处于中等级别。

Geographical information system （GIS） combined with Geostatistics was applied to reveal the spatial variability of soil fertility indices including soil pH, organic matter, available P, available K and clay in the topsoil （0～20cm） in Gongzhuling Area. The results showed that theoretical semivariogram models of soil pH,organic matter,available K,clay were best described with a spherical model, whereas the available P was best fitted with a pure nugget effect model. The ratios of nugget to sill of clay, available K, organic matter, pH were from 37.27% to 49.66%,indicating that the spatial correlation of the four fertility indices was moderately spatially dependent, and the spatial variability was affected by structural and random factors together. Based on the current criteria of classification, the soil pH and organic matter were mainly distributed in the grade of 2～3, and the available P and available K were in the grade of 2～4, whereas clay was in the grade of 3～4, which showed that the fertility indices in this region were in medium grades.