豫中植烟区土壤速效养分的空间变异分析

利用地统计学和GIS相结合的方法，探讨了豫中烤烟种植区土壤速效氮、磷、钾含量空间变异特征。结果表明:研究区速效氮含量属于偏低水平，而速效钾和速效磷为偏高水平。以速效氮的变异系数为最小，速效磷的变异系数为最大。土壤 pH与速效氮和速效磷都成呈显著的正相关关系，土壤有机质与速效氮、速效磷和速效钾都达到极显著的正相关关系。研究区3种土壤速效养分中，除了速效氮为线性模型外，速效钾和速效磷都是球状模型。速效磷和速效钾属于中等强度的空间变异性，而速效氮属于弱的空间相关性。本烤烟种植区土壤速效养分的等值线图可更准确和直观地了解研究区土壤养分的空间分布，从而为精确施肥提供依据。

Spatial Variability of Available Soil Nutrients in Tobacco Planting Fields in Central He'nan Province

Geostatistics method with geographic information system(GIS),was applied to study the spatial variability of available soil nutrients of tobacco planting fields in Central China. The results showed that the contents of available N were at lower level, while the contents of available P and available K were at high levels. The coefficient of variation of available N is the smallest among three nutrients, while the coefficient of variation of available P was the greatest. Analysis of the isotropic variogram indicated that the contents of available N in tobacco planting fields were well described by liner model, while the contents of available P and available K were well described by spherical models. Available K and P had a medium spatial autocorrelation, while the available N had weak autocorrelation. Correlation matrix of soil nutrients revealed that there was significant positive correlation between soil pH and available N and available P in the study regions, while there was significant positive correlation between soil organic matter and available N, available P and available K. The maps generated by ordinary Kriging also revealed the distribution of available soil nutrients in central He'nan Province, which can provided the basis for precise fertilization.