Geochemistry Characteristics Of Soil Nutrient Elements And Soil Quality In Shunyi District In Beijing

Soil,as a major part of ecosystem,closely correlates with lithosphere,atmosphere and hydrosphere.Soil works as not only the ecological resource for countries,but also defines the fundamental the quality of agricultural production.The nutrient elements in soil also play an important role in process of plant growth and indirectly affect human health.Understanding soil properties and their spatial variability are necessary for land use and management.In recent years,with the continuous progress of regional geochemical survey,as well as the development of spatial variation theory and technical tools,spatial analyzation of soil element has been promoted,which provides a scientific basis for optimizing soil management and improving efficiency.In this paper,we took Shunyi District of Beijing as the target region and analyze its main soil nutrient element.The geochemical characteristics and main sources of K,P,Ge,Se,N,Ni,V elements in soil and the influence of soil properties on their contents were studied by using various geochemical theories and methods,such as multivariate statistics and geostatistical analysis.The soil environmental quality level was evaluated through considering the theoretical research and actual environment.The main results were discussed as followed:1)According to the descriptive results of concentration of soil nutrients,the mean content of K₂O in topsoil was higher than the mean value of background in Beijing and China.However,the average content of P,Se,Ge,V,N and Ni in topsoil were lower than the mean values of background in Beijing and the whole country,indicating that the nutrient elements in topsoil in Shunyi District was relatively deficient.2)The results showed the spatial distribution of the nutrient elements in subsoil were mainly in the normal distribution,while the nutrient elements in the topsoil were not in normal distribution.The spatial distribution of K,Ge,Ni and V were influenced by the natural factors of parent rock and weathering process.The spatial distribution of N,P and Se were mainly influenced by the human activities.Spatial variation analysis result showed that K,Ge,Se and V had medium spatial correlation,which addressed the influence of both structure factors and random factors.P had weak spatial variance in large range,mainly result from random factors.3)Through multivariate statistical analysis of the data,it was found that there was a significant correlation between soil nutrient elements.Natural background and human activities were the main factors,which affect the content of soil nutrient elements.Meanwhile,according to the results of cluster analysis,V,Ni,Al₂O₃/Si O₂,Fe₂O₃ and Ge were classified into one category,which was correlated with the natural factors such as soil parent rock,forming process,organic matter content,climate conditions and plants.Se,N,P and TOC were considered as the second class,which were closely correlated with agricultural production activities.4)According to the evaluation standards of soil quality,the soil quality of Sunyi was classified.Shunyi soil belongs to alkaline soil,the content of K was at the relatively adequate level.The content of organic matter,N and the beneficial trace elements were relatively lower.According to the quality standards of N,P and K in soil,the evaluation level of soil nutrients in Shunyi belongs to the third level.According to the comprehensive grade distribution map of soil nutrients in Shunyi,the soil quality on both sides of Chaobai River,Liqiao town were the best,which provides the better conditions for agricultural production.