Environmental impact assessment of orchard soils by the heavy metal concentration in Yantai City of Shandong Province, China

With aims of improvement of soil fertility management, achievement of safe crop production and development of sustainable agriculture in the orchard, surface and subsurface soil samples were collected at nine different orchards in the two regions of Dashitong and Jiajiazhongchun in Yantai City, Shandong Province, China. Concentrations of selected heavy metals in soil were determined to carry out the environmental impact assessment of the orchard soils. The soils in Dashitong where 50-year-old trees are growing showed a clear tendency of Cu accumulation, and the simple pollution index was 0.45 for Cu as a whole. The Cd concentration exceeded the soil environmental standard in all soils to show the simple pollution index of 1.73. The overall pollution index of the soils was 1.27, which indicated the pollution status of "slightly polluted" in the orchard soils. In order to reduce the heavy metal concentration of the orchard soils, the mixed cropping with crops such as soybean is desirable to make absorption of heavy metals by the crops as much as possible, in addition to application of organic fertilizer of the environmental preservation type having no or safe-level heavy metal.