Abstract: 【Objective】The objective of this study was to explore the spatial distribution of soil available micro-elements, and to provide a firm foundation for scientific formulated fertilizer. 【Method】One thousand and seventy six soil samples were collected from an area of 1075 km2 in Pinggu county of Beijing and analyzed for concentrations of DTPA-Cu，DTPA-Zn，DTPA-Fe and DTPA-Mn in topsoil（0-20cm）and subsoil（20-40cm）respectively. The general statistics and geostatistics methods were used to analyze the data. 【Result】The mean value of topsoil soil DTPA-Cu，DTPA-Zn，DTPA-Fe and DTPA-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 micro-elements was more than that of subsoil. The result of semivariance analysis showed the topsoil spatial heterogeneity ranges of DTPA-Fe and DTPA-Mn were 21.60 km and 45.27 km respectively, DTPA-Cu and DTPA-Zn were 3.06 km and 2.89 km respectively. The subsoil range of available micro-elements was obviously different from topsoil, which was DTPA-Mn＞DTPA-Cu＞DTPA-Zn＞DTPA-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 DTPA-Fe and DTPA-Mn were mainly induced by topology, soil types, soil properties etc, while topsoil DTPA-Cu and DTPA-Zn were affected by land use types. And the concentrations of DTPA-Cu and DTPA-Zn were significant higher in orchard and vegetable land than in field. The spatial distribution of subsoil micro-elements was similar with the topsoil micro-elements, which exhibited vertical distribution patterns.【Conclusion】Fertilizer and pesticide application resulted in soil DTPA-Cu and DTPA-Zn higher content of Pinggu county . The higher content of soil DTPA-Zn should be inspected.

Key words: mountain-and-plain combing zone, available micro-element, spatial variability