沈阳市苏家屯区耕层土壤养分空间变异性研究

利用地统计学和地理信息系统相结合的方法。研究了沈阳市苏家屯区耕地土壤(0～20cm)有机质、速效氮、速效磷、速效钾含量的空间变异性特征。结果表明，各变量符合正态分布或经对数转换后符合正态分布，最佳的变异函数理论模型均为球状模型，有机质具有较强的空间相关性(C0与C0+C比值为24．11％)，速效氮、速效磷、速效钾具有中度的空间相关性(C0与C0+C比值分别为29．53％、60．77％、58．82％)，各变量的空间自相关距离分别为26．051、28．293、15．132和23．813km。有机质和速效氮的空间变异主要受结构性因子(如成土因子)的影响，速效磷和速效钾主要受随机性因子(如施肥)的影响，Kriging插值绘制出的养分含量空间分布图显示了养分的空间分布格局，它将有助于进一步监测养分动态，为农业和环境管理提供数字地图支持。

Spatial variability of soil nutrients in cultivated surface soil of Sujiatun District, Shenyang City

The spatial variability of organic matter (OM), available nitrogen (AN), available phosphorus (AP), and available potassium (AK) in 0~20 cm horizon in cultivated soils of Sujiatun District, Shenyang City were investigated using geostatistics and geographic information system (GIS). Data of each variable fitted normal distribution or normal distribution after log transformation, and a spherical model for semivariogram fitted all the variables. Semivariograms indicated that OM content strongly spatially dependent with the ratio of nugget to sill of 24.11 % . The contents of AN, AP and AK were moderately spatially dependent with the ratio of nugget to sill of 29.53%, 60.77% and 58.82%, respectively. The ranges of spatially dependent for OM, AN, AP and AK were 26.051, 28.293, 15.132 and 23.813 km, respectively. The spatial variability for OM and AN was fundamentally affected by structural factors such as soil formation factors, and that for AP and AK was by random factors such as fertilization. Kriging maps showed the spatial distributions of the four variables, which were useful in monitoring nutrient changes and providing quantitative support to decision and policy making for agriculture and environment management.