An Auxiliary Method for Evaluating Soil Erosion and Pollution by Magnetic Susceptibility on Black Soil Farmland

Soil heavy metal (HM) pollution constitutes a global environmental issue. Measuring the soil magnetic susceptibility (MS) is straightforward and expeditious. However, the correlation of HMs with MS in agricultural soils remains ambiguous. This study aimed to determine the correlation between HMs and soil MS on Black Soil farmland in Northeast China. Soil samples were selected from three typical black soil farmland slopes in the 0–20 cm topsoil. Based on measurable magnetic and chemical indexes, the pattern of soil MS along the slope and the environmental implications of HMs were evaluated. The results show that MS was higher on the lowerslope of farmland hillslopes corresponding to deposition position; the most prominent HMs in the studied farmland are Pb and Ni; the predominant source of Pb and Ni is agricultural machinery, while the source analysis revealed that the primary source of Cu is chemical fertilizers; and the correlation analysis showed a negative correlation between MS and Cu, Cr, Pb, and Zn, and positive correlation with Ni, and Mn. These results prove the relationship between magnetism and heavy metal elements, which providing the possibility of using soil magnetism to estimate soil pollution. Further data are needed to verify the exact correlativity of MS and HMs in soil with different land uses.