基于GIS的鲁东南典型丘陵平原区农田土壤养分空间变异特征及影响因素研究

以鲁东南丘陵平原区的某镇为例,利用采集的200个农田表层土壤样点数据,运用地统计学方法研究了土壤中有机质(SOM)、全氮(TN)、碱解氮(AN)、速效磷(AP)和速效钾(AK)含量的空间变异特征及其影响因素。结果表明:SOM、TN、AN、AP和AK的平均含量分别为13.52 g/kg、0.75 g/kg、87.27 mg/kg、50.55 mg/kg和103.20 mg/kg,土壤养分含量总体属于稍缺水平,变异系数依次按大小排序为AP>AN>AK>TN>SOM,全部为中等变异程度。地统计分析表明,5种土壤养分的变异函数符合指数模型,通过普通克里格法对土壤养分进行空间插值来绘制了养分含量等级空间分布图,总体来说研究区土壤的有机质和全氮含量水平都较低,其他有效组分在含量等级及分布范围相对于有机质和全氮的状况要稍好。地形地貌、土壤类型和土地利用方式等因素对研究区土壤养分的空间变异程度有显著影响,其中地形地貌、土壤类型等结构性因素的影响程度较强。

Spatial Variability Characteristics and Influencing Factors of Soil Nutrients in Farmland in Typical Hilly and Plain Area of Southeast Shandong

In this research, a town was chosen as a case in the hilly and plain area of southeast Shandong Province. The spatial variable characteristics of organic matter (SOM), total nitrogen (TN), alkali-hydro-nitrogen (AN), available phosphorus (AP) and available potassium (AK) in soil and their influencing factors were studied by geostatistics method based on the data collected from 200 farmland surface soil samples. The results show that the average content of SOM, TN, AN, AP and AK are 13.52 g/kg, 0.75 g/kg, 87.27 mg/kg, 50.55 mg/kg and 103.20 mg/kg, respectively. The soil nutrient content as a whole is slightly deficient. The variable coefficient of the 5 kinds of soil nutrients is ranked as AP>AN>AK>TN>SOM in order of size, all with moderate degree of variation. Statistical analysis shows that the variation function of the 5 kinds of soil nutrients accords with exponential model. The spatial distribution of soil nutrient content grade was mapped through the ordinary Kriging spatial interpolation method. Overall, the level of soil organic matter and total nitrogen content in the study area are low. In terms of the content level and distribution range, other effective components are slightly better. Topographic and geomorphic factors, soil types, land use patterns and other factors have a significant influence on the spatial variation degree of soil nutrients in the study area, among which, structural factors such as topographic and geomorphic factors and soil types have a strong influence.