北京东南郊农田土壤养分状况及空间分布特征

Soil Nutrient Status and Spatial Distribution Characteristics of Farmland in Beijing East-South Suburb

采用均匀布点、重点加密、充分考虑农田种植类型的原则,采集北京市大兴区长子营镇58份土壤表层样品,用土壤养分常规分析和SPSS相关分析方法,研究北京东南郊农田土壤养分状况及空间分布特征。结果表明：土壤有机质、全氮、有效磷、速效钾的含量及pH值的平均值分别为14.5g/kg、1.13g/kg、82.1mg/kg、129.1mg/kg和8.16。以全国土壤养分分级方法为评价标准,土壤全氮含量为中等水平,土壤有机质含量为中等偏下水平,有机质含量主要集中在Ⅲ～Ⅴ级,约占87.9%;土壤有效磷含量水平较高,主要集中在Ⅰ～Ⅲ级,约占87.9%,且有效磷的变异系数为113.73%,属于强变异,呈明显的区域不均匀分布;土壤速效钾含量为中等偏上水平。相关系数分析结果表明,5种养分含量均存在显著相关性。不同农田类型间比较,土壤有机质、全氮和有效磷的含量均表现为设施菜田〉露地菜田〉粮田〉果园,速效钾的含量表现为设施菜田〉果园〉露地菜田〉粮田。采用ArcGIS中的无偏最佳估值的普通克立格方法进行空间插值,分析表明,长子营镇土壤养分的空间分布特征为中北部含量高于南部,尤其以中部地区含量最高。

With the principle of uniform distribution,increasing the sampling density at crtical area,and considering plantation types,fifty-eight farmland surface soil samples were collected from Zhangziying town in daxing District to investigate soil fertility status and nutrient spatial distribution characteristics via chemical analysis and SPSS correlation analysis.The results showed that the average values of soil organic matter,total N,available P,available K contents,and pH value were 14.5g/kg,1.13g/kg,82.1mg/kg,129.1mg/kg and 8.16,respectively.To evaluate the soil fertility according to national soil nutrient classification method,soil total N and organic matter contents were at the medium level and lower middle level.For soil organic matter content,87.9%soil samples fell in the scope of gradeⅢ-Ⅴ.Totally,soil available P content was at higher levels,which was mainly at the gradeⅠ-Ⅲfor 87.9% samples.But the variation coefficient of available P was 113.73% which showed that available P spatially varied greatly.Soil available K content was at the middle level.The results of correlation analysis showed that,five kinds of soil nutrient contents were correlated significantly.Comparing soil nutrient content of different type of farmland,the content of organic matter,total N,and available P were in following order greenhouse vegetable〉open field vegetable〉crop field〉orchard.While the content of available K was performed by greenhouse vegetable〉orchard〉open field vegetable〉crop field.With Ordinary Kriging method in the geo-statistic module of ArcGIS,the spatial distribution characteristics showed that soil nutrient was higher in the north and the central area than the south area of the town;especially the central region exhibited the highest levels.