湘南紫色丘陵耕作区土壤肥力质量空间变异研究

Spatial Variation of Soil Fertility Quality in Cultivation Areas of Purple Hilly Region from Southern Hunan Province

本文在分析土壤各单项肥力要素空间变异基础上,结合Fuzzy综合评价法和GIS技术研究了湘南紫色丘陵耕作区土壤肥力质量空间变异,为该区合理规划、开发土壤资源,科学培肥提供依据。研究结果表明:选取的8种肥力指标具有一定空间相关性,有机质、全氮、有效磷、速效磷值的空间异质比(块金值与基台值的比值)分别为100.0%、100.0%、87.9%和99.9%,属于空间弱相关,而pH、碱解氮、全磷、全钾的空间异质比分别为33.8%、63.3%、66.1%、73.7%,属中等空间相关;各单项肥力要素空间分布随土地利用变化呈不同的规律性变化。研究区土壤肥力质量偏低,为Ⅱ、Ⅲ和Ⅳ等,分别占整个区域面积的46.2%、19.6%和34.2%;不同土地利用类型表现为:水田土壤肥力质量较优,主要为Ⅱ等;丘陵下部梯田和地势较低的坡耕地土壤肥力质量为Ⅲ等;地势较高的地块和荒地均为Ⅳ等。

With the aim to provide reference for soil resource exploration and scientific fertilization, spatial variation of fertile indices was studied in purple hilly region of Southern Hunan Province by means of Fuzzy theory and GIS. The results showed that： there was some spatial dependence in 8 fertile indices. The nugget to sill ratio of organic matter, total N, available P were 100.0%, 100.0%, 87.9% and 99.9%, respectively, which indicated a weak spatial dependence. However, nugget to sill ratio ofpH, available N, total P and total K were 33.8%, 63.3%, 66.1% and 73.7%, respectively, which implied a moderate spatial dependence. Meanwhile, the spatial distribution of 8 fertile indices varied with land-use. The integrated fertility index （1FI） in the sampling region ranged from Ⅱ-Ⅳ grade and the areas covered were 46.2%, 19.6%, and 34.2% of the total area, respectively for the Ⅱ grade, the Ⅲ grade, and the IV grade. Soil quality varied with land-use, i.e., IFI of paddy field belonged to the Ⅱ grade, that of terrace located in lower hilly area and sloping land located in lower hill-side was the Ⅲ grade; and that of upper bill-side and wasteland belonged to the Ⅳ grade.