The effects of vermicompost produced by Eisenia foetida on organic carbon content

soil acidity and Cu/Pb speciation were studied in acid soil contaminated by heavy metals through simulated pot experiment. Vermicompost was made with cattle waste and rice straw

respectively. The results showed that soil total organic carbon content increased by 25%～83% in the soil with 2.5%～10% amount of vermicompost

and the soluble organic carbon of the cattle waste vermicompost was significantly higher than that of the rice straw vermicompost (P＜0.05)

and there was no significant difference in other organic carbon content between the two kinds of vermicompost. Vermicompost increased the soil pH (H2O) value by 0.38～1.13 pH units

and reduced exchangeable hydrogen and aluminum content by 41%～77% and 57%～94%

respectively. The vermicompost reduced soil acidity significantly

and soil pH（H2O）value was 0.35～4 times higher than that of the control. For reducing acidity of the soil with 10% amount of vermicompost

the effect of cattle waste vermicompost was 22% higher than that of rice straw vermicompost. The vermicompost reduced the contents of soluble-exchangeable Cu and Pb in the soil by 19%～56% and 10%～40%

respectively

and increased the contents of organic state Cu and Pb by 22%～70% and 29%～70%

respectively. The vermicompost could significantly reduce the activity of Cu and Pb in soil. The effects of vermicompost on reducing Cu and Pb activity were 0.58～9.6 times and 0.16～3.4 times higher than those of the control. The effects of rice straw vermicompost on reducing activity of Cu and Pb were 11%～61% and 1%～32% higher than those of cattle waste vermicompost. In conclusion

vermicompost reducd soil acidity and Cu/Pb activity greater than that of control

cattle waste vermicompost was better on reducing soil acidity

and rice straw vermicompost was better on reducing Cu/Pb activity. The total organic carbon

microbial biomass carbon

Humic acid carbon and fulvic acid carbon in vermicompost all played important roles in reducing soil acidity. Cu and Pb activity

and the action efficiencies of organic carbon in the vermicompost on soil acidity and Cu/Pb activity were higher than those in the control material with the same amount of organic carbon.