土壤数据库在土壤学研究工作中作为一种存储、分析工具的重要性是不言而喻的.本研究利用ArcGIS和Visual FoxPro建立了包括8 830个图斑、269个土壤剖面数据的无锡和常州市1:5万土壤数据库,根据“土壤质量演变规律与持续利用‘973'项目”的土壤肥力质量指标(pH、速效磷和速效钾)和全国养分分级标准(全氮)编制出土壤表层(0~15 cm)pH、全氮、速效磷和速效钾的空间分异图,从中表明pH 1~2级的土壤占整个研究区面积90%左右;土壤养分全氮、速效磷和速效钾的空间分布有明显共同特征-太滆平田区养分含量要显著高于其他地区.对不同母质和不同土壤类型(亚类级别)间的土壤表层容重、粘粒、pH、有机质、全氮、全磷、全钾、速效磷和速效钾进行了方差分析,结果显示,除全氮之外,其他属性均有显著差异.在1:5万尺度范围内,成土母质对pH、容重、全磷、有机质和速效钾起到主导作用,土壤类型对pH起到主导作用,成土母质对土壤属性的影响程度要大于土壤类型.
There is no doubt that soil database is an important mnemonic and analytic tool for soil studies. This paper deals with spatial heterogeneity of soil properties with the aid of a 1 : 50 000 soil database of Wuxi and Changzhou cities, which is built up with the ArcGIS and Visual FoxPro technology and consists of 8 830 mapping polygons and data of 269 soil profiles. A map is compiled in the accordance to the criteria for grading of soil fertility fixed up in Research Project "973" on Principles of Soil Quality Changes and Sustainable Land Use (for pH, available phosphorus and potassium) and in the National Soil Nutrient Grades (for total nitrogen) to show the spatial heterogeneity of pH, total nitrogen, rapidly available phosphorus and potassium in the surface soils (0 - 15 cm) of the study area. The map shows that soils of grade 1 - 2 in pH value constitute about 90% of the total study area, and that the most part of the soils on the flat Tai Lake-Ge Lake Plain are commonly in grade 1 in total nitrogen, rapidly available phosphorus and potassium. Moreover, variance analysis is conducted of the data of physico-chemical properties of the soils of various parent materials and of various types (soil subgroups). Result shows that all determined soil properties, except for total nitrogen, are quite heterogeneous. It is concluded that, at the scale of 1 : 50 000, parent material is the dominant factor for the spatial heterogeneity of pH, bulk density, total phosphorus, organic matter and rapidly available potassium, while soils type for the spatial heterogeneity of pH. That is to say, the impacts of parent materials have stronger impacts on spatial heterogeneity of soil properties than soil types do.