基于GIS和地统计学的土壤养分空间变异特征研究——以河北省遵化市为例

基于地理信息系统(GIS)和地统计学研究了河北省遵化市土壤表层(0～20cm)碱解氮、全氮、速效钾、速效磷和有机质等5种养分要素的空间变异规律.应用GIS能够将系统变量的属性数据同地理数据相结合,使大区域范围内进行地统计学分析变得较为方便.研究表明,全氮、碱解氮、速效磷、有机质变异函数曲线的理论模型符合球状模型,速效钾的理论模型表现为指数模型和有基台值的线性模型的套合结构;碱解氮、全氮、速效磷、有机质的空间变异主要是由随机性因素引起的,但程度有所差异,全氮和有机质由随机性因素引起的空间异质性程度较高,碱解氮和速效磷较低;速效钾的空间变异则主要是由结构性因素引起;5种养分要素的空间自相关程度都属于中等的空间自相关,但空间变异的尺度范围不同,碱解氮和速效磷变异尺度基本相近,为5和5.5km;全氮较大,为14.5km;有机质为8.5km;速效钾的变异尺度有两个,0～3.5km主要以指数模型为主,3.5～25.5km范围内以有基台值的线性模型为主.5种养分要素的各向同性的范围不同,碱解氮和速效磷在整个范围(0～28km)都表现出各向同性,全氮和有机质的其次,为0～10km;速效钾的较小,为0～8km.

Spatial variability of soil nutrients based on geostatistics combined with GIS-A case study in Zunghua City of Hebei Province

Geostatistics combined with GIS was applied to analyze the spatial variability of soil nutrients in topsoil (0～20cm) in Zunghua City of Hebei Province.GIS can integrate attribute data with geographical data of system variables,which makes the application of geostatisitics technique for large spatial scale more convenient.Soil nutrient data in this study included available N (alkaline hydrolyzing nitrogen),total N,available K,available P and organic matter.The results showed that the semivariograms of soil nutrients were best described by spherical model,except for that of available K,which was best fitted by complex structure of exponential model and linear with sill model.The spatial variability of available K was mainly produced by structural factor,while that of available N,total N,available P and organic matter was primarily caused by random factor.However,their spatial heterogeneity degree was different:the degree of total N and organic matter was higher,and that of available P and available N was lower.The results also indicated that the spatial correlation of the five tested soil nutrients at this large scale was moderately dependent.The ranges of available N and available P were almost same,which were 5 km and 5.5km,respectively.The range of total N was up to 18km, and that of organic matter was 8.5km.For available K,the spatial variability scale primarily expressed exponential model between 0～3.5km,but linear with sill model between 3.5～25.5km.In addition,five soil nutrients exhibited different isotropic ranges.Available N and available P were isotropic through the whole research range (0～28km).The isotropic range of available K was 0～8km,and that of total N and organic matter was 0～10km.