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以位于太湖流域的浙江省平湖市为例,采用GIS与地统计学相结合的方法对其耕层土壤(0～20cm)的有机质、全氮、速效磷、速效钾等4种养分要素的空间变异特征进行了分析。结果表明:有机质和全氮变异函数曲线的理论模型能很好地符合球状模型;速效磷经对数转换后也符合球状模型;而速效钾的变异函数曲线则符合指数模型。有机质、全氮和速效磷具有很强的空间相关性,说明受母质、地形、土壤类型等自然的结构性因素影响较大;速效钾具有中等的空间相关性,说明由施肥、作物、管理水平等随机因素引起的空间异质性起很大作用。整个研究区东南部土壤质地较轻,大量施肥在提高其作物产量的同时,也可能会带来农业非点源污染等问题。
Taking Pinghu City, Zhejiang Province, located in the Taihu Lake Basin as an example, the effects of four nutrient elements, including organic matter, total nitrogen, available phosphorus and available potassium, on topsoil (0-20 cm) Spatial variability characteristics were analyzed. The results show that the theoretical model of the curve of organic matter and total nitrogen can well fit the spherical model; the available phosphorus also accords with the spherical model after logarithmic transformation; and the curve of available potassium is consistent with the exponential model. There was a strong spatial correlation between organic matter, total nitrogen and available phosphorus, which indicated that natural structural factors such as parent material, topography and soil type were more influential. Available potassium had a moderate spatial correlation, indicating that there was a moderate spatial correlation between available potassium, crop and management level Such as random factors caused by the spatial heterogeneity played a significant role. Soil texture in the southeastern part of the study area is relatively light and large amount of fertilizers may raise issues of crop non-point source pollution while improving crop yield.