基于GIS的湖北省江陵县土壤养分空间变异研究

Spatial Variability of Soil Nutrients Based on GIS in Jiangling County of Hubei Province

结合应用GIS与地统计学,研究了湖北省江陵县土壤表层(0～20cm)碱解氮、速效磷、速效钾和有机质等属性的空间变异规律。结果表明,所有观测养分的变异系数均属于中等变异强度。结构分析结果表明,碱解氮、有机质、速效磷变异函数曲线的理论模型符合指数模型,速效钾的理论模型符合高斯模型;碱解氮、速效磷、速效钾的空间变异主要是随机性因素引起的,但程度有所差异,有机质的空间变异则主要是结构性因素引起的;4种养分要素的空间自相关程度都属于中等的空间自相关,但尺度范围不同,碱解氮、有机质、速效磷的空间相关距离较大,达49.1km,速效钾自相关距离为17.9km。采用Kriging插值方法生成了养分分布等值区图,可更直观地了解县域的土壤养分丰缺状况。

Geostatistics combined with GIS was applied to analyze the spatial variability of soil nutrients in topsoil(0～20 cm) in Jiangling County of Hubei Province.The statistical results showed that the coefficients of variation of all the observed nutrients belonged to the middle degree.Semi-variance analysis indicated that the semivariograms of available N,available P,and organic matter were best-fitted by exponential model,except for that of available K,which was best-fitted by Gaussion model;The spatial variability of available N,available P and available K were primarily caused by random factor,while that of organic matter was mainly produced by structural factor.The results also indicated that the spatial correlation of the four tested soil nutrients at this large scale was moderately dependent,but spatial scale was different.The ranges of available N,organic matter and available P were same,which were 49.1 km;the ranges of available K was 17.9 km,respectively.The Kriging method and GIS technique were applied to calculate the unobserved points and were used to generate the filled contour map.The richness and deficient status of soil nutrients could be viewed from the map.