湘南丘岗红壤地区土壤肥力质量指标的空间变异特征

采用地理信息系统(GIS)和地统计学方法研究了湘南丘岗红壤地区土壤表层(0～20 cm)pH值、有机质、碱解氮、有效磷、速效钾、全氮、全磷、全钾8项土壤肥力指标的空间变异特征.结果表明:土壤pH、有效磷、全氮和全钾的理论模型为球状模型,有机质、碱解氮和速效钾的理论模型为指数模型,全磷的理论模型为高斯模型；碱解氮和全磷的基底效应分别为13.6％、19.0％,表现出强烈的空间相关性,土壤pH、有机质、有效磷、速效钾、全氮和全钾的基底效应分别为28.7％、29.9％、54.7％、53.1％、55.6％、73.0％,具有中等的空间相关性；研究区域的书林寺村南部和官山坪村北部以石灰岩风化物母质为主,土壤肥力较高,属Ⅰ～Ⅲ级,幸福桥村区域以板岩风化物母质为主,土壤肥力为Ⅳ级,官山坪村南部以第四纪红土母质为主,土壤肥力属Ⅴ级,应重视第四纪红土母质地区土壤退化防治和肥力恢复调控.

Spatial variability of soil fertility quality indices in red soil region

Geographical information system(GIS)combined with geostatistics was applied to reveal the spatial variability of soil fertility quality indices including soil pH,organicmatter,available N,available P,available K,Total N,Total P and Total K in the topsoil(0-20 cm)of southeastern Hunan province.The results showed that theoretical semivariogram models of soil pH,available P,Total N and Total K were best described with an spherical model,whereas the organic matter,available N and available K were best fitted with a exponential model,Total P was best described with an gaussian model.The ratios of nugget to sill of available N and Total P were 13.6%,19.0%,respectively,indicating there existed strong spatial correlation.The ratios of nugget to sill of pH,organicmatter,available P,available K,Total N and Total K were 28.7%,29.9%,54.7%,53.1%,55.6%,73.0%,respectively,indicating a moderate spatial correlation.In the red soil region,the soil IFI(integrated fertility index) was closely related with parent material,based on which the fertility quality of the soil in north of Guanshanping village and south of Shulingsi village developed from limestone parent material belonged to theⅠ,Ⅱ and Ⅲ degree,which was high,the fertility quality of soil in Xingfuqiao village developed from slate parent material belonged to Ⅳ degree and the fertility quality of soil in south of Guanshanping village developed from quaternary red earth parent material belonged toⅤdegree.