Abstract: A field survey of agricultural soils in the Sanjiang Plain was carried out of agricultural soils using the grid sampling method for analysis of spatial distribution of heavy metals (As, Cr, Cu, Pb and Zn) in the soil by using the geo-statistics and traditional statistics methods. The studied area was 7.31× 10⁴ km² in total and it was divided into 16km×16 km grids, providing 244 sampling points. Results show that in this area, the heavy metals varied sharply in terms of spatial distribution in the soil with variation coefficients ranging from 30.67%-66.89%; The heavy metals were all quite high in spatial autocorrelation and their spatial autocorrelation was rather wide in range. As and Cr was <20% in C₀/(C₀+C), showing their spatial variations were mainly affected by natural factors, like soil parent material, topography and climate, while Cu, Pb and Zn varied in the range of 35.8%-43.2% in C₀/(C₀+C),  showing that their main affecting factors were non-structural ones; The heavy metals differed in spatial distribution and were quite obvious in spatial variation on a small area scale. They did not have any specific patterns in spatial distribution on a large area scale, except Cu. A surface soil heavy metals spatial distribution map was worked out using the Kriging interpolation method, revealing ,that heavy metal concentrations in the soil are closely related to soil type, physical-chemical properties, land-use pattern, mining, agricultural mechanization intensity, and agricultural irrigation.  

Key words: soil heavy metals, spatial distribution, impact factor, geo-statistics, Sanjiang Plain