滇中东部典型岩溶区农田土壤肥力评价

Evaluation of Farmland Fertility of Typical Karst Area in Central and Eastern Yunnan

云南省岩溶面积分布广,评价云南不同县域土壤肥力,可为岩溶区土壤资源的利用、改良和农业生产布局提供基础。通过对滇中、滇东岩溶区宣威、石林和砚山农耕地土壤及其剖面调查,采集土壤样品248份,测定土壤全氮、有效磷、速效钾、有机质和pH,采用主成分分析(PCA)法对研究区土壤肥力进行综合评价。结果表明:宣威、石林、砚山土壤5项指标属中等变异程度,土壤剖面AB层与A层(A1和A2)土壤全氮、有效磷、速效钾、有机质含量差异显著,AB层和B层土壤全氮、有效磷、速效钾、有机质含量差异不显著。通过主成分分析法提取出3个主成分,反映了原信息量的82.954%,第一主成分以有机质和全氮贡献最大,第二主成分以有效磷贡献最大,第三主成分以速效钾贡献最大,土壤肥力综合得分为宣威(0.231)>石林(–0.289)>砚山(–0.335)。这一结果可为岩溶区土壤养分调控和发展高原特色农业提供参考依据。

The karst area is widely distributed in Yunnan Province, the evaluation of farmland fertility in different counties in karst areas can provide scientific bases for the utilization, improvement and agricultural production layout of soil resources. In this study, 248 soil samples were collected from farmland profiles in Xuanwei, Shilin and Yanshan in the karst areas of central and eastern Yunnan, total nitrogen, available phosphorus, available potassium, organic matter and pH of the samples were determined, and then soil fertilities of farmlands were assessed by the principal component analysis(PCA) method. The results showed that the determined five soil indexes were moderately variable in tillage layers in the three regions. Total nitrogen, available phosphorus, available potassium and organic matter were significantly different between AB layers and A(A1 and A 2) layers, but weren’t significantly different between AB layers and B layers. Three principal components were extracted by PCA which reflected 82.954% of the original information. The first principal component was organic matter and total nitrogen, the second one was available phosphorus, the third one was available potassium, the comprehensive scores of soil fertility was in order of Xuanwei(0.231) > Shilin(–0.289) > Yanshan(–0.335). The above results can provide reference for soil nutrient regulation and developing plateau characteristic agriculture in karst areas.