小尺度土壤养分的空间变异及其影响因素探讨—以江苏省无锡市典型城乡交错区为例

以江苏省无锡市城乡交错区为例,在8km2范围内,采集102个土壤表层样,利用地统计学和G IS相结合的方法,研究了土壤全量和速效氮、磷、钾的空间变异特征,并对其影响因素进行了探讨。结果表明土壤养分空间变异程度从大到小依次为:土壤全氮>土壤全磷>土壤速效磷>土壤速效氮>土壤速效钾>土壤全钾。土壤全氮空间变异受到土壤类型的影响,土壤全磷的空间变异与居民点分布有关,土壤全钾空间变异与土壤粘粒关系最密切。土壤全量养分和相应的速效养分具有显著相关关系,在空间分布上,也分别存在不同程度的相似性。同时土壤全磷和土壤速效养分受土地利用影响也较大。研究还表明,城乡交错区土壤氮、磷流失风险增加,需要实施有效措施控制氮、磷肥料的过度施用。

Spatial Variation of Soil Nutrients and its Affecting Factors at Small Scale--A Case Study of Peri-urban Areas in Wuxi Jiangsu Province

This paper introduces a case study on spatial variation of soil nutrients,i.e.total N(TN),total P(TP),total K(TK),available N(AN),available P(AP) and available K(AK) and its influencing factors in a peri-urban area at Wuxi City Jiangsu Province of China with the aid of both geostatistic and GIS.102 topsoil samples are collected in an area of 8km~2 for study.Results show that the spatial variability of soil nutrients follows the order of TN > TP > AP > AN > AK > TK.The spatial variation of TN is affected by soil types,that of TP is affected by the location of residential communities,and that of TK is affected by soil clay content(<0.002mm).The total content of a nutrient element is significantly correlated with the available content of the element,and similar correlation tendency is found at various extents in spatial variations of soil nutrients.Results also show that spatial variations of TP and available nutrients are greatly affected by land use patterns.It is suggested that excessive application of N and P fertilizers in peri-urban areas of the city should be effectively controlled for the risk of N and P losses from soils in those areas is increasing.