Influence of Heavy Metal Cadmium on Biological Characteristics of Agricultural Soils

[Objective] The research aimed to explore the influence of low concentrations of heavy metal cadmium on soil biological characteristics,which provided the experimental basis for the establishment of biochemical indicators platform that could characterize the degree of the contamination of the soil by heavy metal cadmium.[Method] The influence of heavy metal cadmium on biological characteristics of agricultural soils was studied by measuring the physical-chemical properties and biological activities of different levels of cadmium contaminated soils.[Result] Within the scope of pH 4.42-7.58,the effective cadmium content 0-1.860 mg/kg,the increase of effective cadmium promoted microbial activity and increased microbial respiration and metabolicsm.But when the effective cadmium content exceeded to 0.6 mg/kg,the inhibitory effect was generated.Catalase activity wasn't significantly correlated with cadmium content.Negative relationships were observed between urease activity and effective cadmium content.Microbial biomass increased logarithmically with the increase of the effective cadmium content.[Conclusion] The selection of soil enzyme activities to characterize the degree of soil heavy metal contamination is reasonable.