喀斯特地区烟田土壤养分的空间变异特征

以我国典型的喀斯特地区—贵州省毕节地区为研究区域,利用地统计学和地理信息系统(GIS)相结合的方法对烟田土壤养分的空间变异特征进行研究,皆在为喀斯特地区烟草种植的平衡施肥及生态环境保护提供依据。描述性统计结果表明,研究区烟田土壤各养分指标均属中等程度变异。半方差函数分析表明,研究区烟田土壤全氮、全钾、速效磷变异函数的最适模型是球状模型,全磷和速效钾的最适模型是线性模型,碱解氮、pH和有机质的最适模型为指数模型;速效磷表现为强烈的空间自相关性,主要受结构性因素影响,而全氮、全磷、全钾、碱解氮、速效钾、pH和有机质表现为中等空间相关性,受结构性因素和随机性因素共同影响。普通克里格插值的土壤养分空间分布图表明,研究区域内烟田土壤全氮、全钾、速效磷和速效钾含量分布呈现空间连续分布的特点,而全磷、碱解氮和pH、有机质含量没有明显的分布规律,这主要与喀斯特地区复杂的立地因子和人为影响有关。

Spatial Heterogeneity of Soil Nutrients in Karst Tobacco-growing Areas

In order to provide basis for tobacco balanced fertilization and ecological environment protection in karst areas,the spatial heterogeneity of soil nutrients in karst tobacco-growing areas of Bijie,Guizhou province,was studied by the methods of geostatistics and GIS.Statistic analysis showed each soil nutrient had moderate variation.Spherical model fitted best for total N,total K and available P,linear model fitted best for soil total P and available K,and exponential model fitted best for other variables.By analysis of ratios of nugget to sill,soil available P showed strong spatial autocorrelation fundamentally controlled by structural factors,while other variables showed moderate spatial autocorrelation affected by both structural and random factors.According to the spatial distribution maps of soil nutrients,the distribution of total N,total K,available P and available K was continuous,other than total P,alkaline N,pH and organic matter,which should be due to the complicated site factors in karst areas and human impact.