Preliminary Study on Spatial Variability and Distribution of Soil Available Microelements in Pinggu District of Beijing

Objective The objective of this study was to explore the spatial distribution of soil available microelements,and to provide a solid foundation for scientifically formulated fertilizer. MethodOne thousand and seventy six soil samples were collected from Pinggu District of Beijing and analyzed for concentrations of available Cu,available Zn,available Fe and available Mn in topsoil (0-20 cm) and subsoil (20-40 cm),respectively. The general statistics and geostatistics methods were used to analyze the data. ResultThe mean value of topsoil soil available Cu,available Zn,available Fe and available Mn were 1.96 mg·kg-1,2.51 mg·kg-1,17.32 mg·kg-1,and 10.91 mg·kg-1,respectively,which were at higher level. The topsoil content of soil available microelements was more than that of subsoil. The result of semivariance analysis showed that the topsoil spatial heterogeneity ranges of available Fe and available Mn were 21.6 km and 45.3 km,respectively,available Cu and available Zn were 3.1 km and 2.9 km,respectively. The subsoil range of available microelements was obviously different from topsoil,and the available Mnavailable Cu available Zn= available Fe. The Kriging method was applied to calculate the unobserved points and was used to generate the contour map. The results illustrated that the spatial distribution of topsoil available Fe and available Mn were mainly induced by topology,soil types,soil properties,etc,while topsoil available Cu and available Zn were affected by land use types. And the concentrations of available Cu and available Zn were significantly higher in orchard and vegetable land than in field. The spatial distribution of subsoil microelements was similar with the topsoil microelements,which exhibited vertical distribution patterns.ConclusionFertilizer and pesticide application resulted in higher content of soil available Cu and available Zn in Pinggu District. The content of available Zn was higher. Attention should be paied to the potential harmfulness to soil environmental quality.