摘要
A laboratory incubation experiment was conducted to evaluate the effects of lead and zinc applied alone or in various combinations on the size of microbial biomass in a red soil. Treatments included the application of lead at six different levels i.e., 0 (background), 100, 200, 300, 450 and 600 μg g -1 soil along with each of the four levels of zinc (0, 50, 150 or 250 μg g -1 soil). Application of lead or zinc alone to soil significantly ( P <0.001) affected the soil microbial biomass. The microbial biomass carbon (C mic ), biomass nitrogen (N mic ) and biomass phosphorus (P mic ) decreased sharply in soils contaminated with lead or zinc. Combined application of lead and zinc resulted in a greater biocidal effect on soil microbial biomass, which was significantly higher ( P <0.001) than that when either lead or zinc was applied alone. Consistent increase in the biomass C:N and decline in the biomass C:P ratios were also observed with the increased metal (Pb and Zn) toxicity in the soil.
Leadandzincarethemetalswelrecognizedfortheirwidespreaddistributionandpotentialrisktotheenvironment.Outofthesetwo,zincisanesen...