| The field experiment was conducted in Miaoyunao Village, Daye County, Huangshi City, Hubei province, China, which is nearby an ancient mining. And the total Cd and Cu content in the surface soil is 2.19mg kg-1 and 368.91mg kg-1 respectively. The experiment was conducted to evaluate the effect of compost on the bioavailability of Cd, biotoxicity of Cu, soil enzyme activities and wheat growth in winter wheat (Triticum aestivum L.)in situ. The objectives of the study were to evaluate the remediating effect of compost on Cd, Cu-contaminated soils.1. The compost in the study showed no significant influence on plant height and the weight of thousand seeds and total protein content of seeds except the highest level. At the lower levels of CM1 and CM2, the height was increased by 1.02 and 1.04 times respectively. However, it was decreased by CM3 and CM4, especially for the highest level, the results show obviously the adverse effects on the plant height. Compared with CM0, the weight of thousand seeds was significantly decreased by 5%-10% and the protein of the wheat was increased by 1%～16% in all compost levels.2. The addition of appropriate quantity of compost was effective in reducing Cd uptake by wheat seeds and stems. The concentration of Cd decreased by 10%～18% in wheat seeds and 68%～72% in wheat stems respectively. However, the content of Cd in seeds and stems for the CM3 and CM4 has no significant differences with control. The Cd content in the roots ranged from 1.70 to 2.21 mg kg-1 as compost addition, equivalent to 7%-29% enhancement compared to the control.3. Compost application resulted in the concentration of organic-bound Cd increased by 0.37 times, no effect on the other Cd fraction in surface soils. In the sub surface soil the organic-bound Cd and the inorganic precipitates Cd was increased with the respect to control. In the rhizosphere soil the organic-bound Cd was increased by 1.9～2.1 with and the inorganic precipitates Cd was decreased corresponding by 23.9%～31.5% the respect to control. No significant differences were found for the soluble/exchangeable Cd and residual Cd amount all levels of compost addition.4. Compare with the control, the Cu uptake by wheat seeds and stems increased by 0.06～1.54 and 0.05～0.33 respectively. The content of Cd in roots for all the compost level has no significant differences with control.5. Compost application increased the soluble/exchangeable Cu and the organic-bound Cu in the surface soil. In the sub surface soil the soluble/exchangeable Cu, the organic-bound Cu and the inorganic precipitates Cd increased with increasing rate of compost addition into soil. Compare to the control the soluble/exchangeable Cu and the organic-bound Cu in rhizosphere soil increased by 1.3～4.8 and 6～15% respectively while the inorganic precipitates Cu decreased by about 13%.6. Compost application increased the soil enzyme activities in contaminated soils. With increasing level of compost application, soil urease activities, soil protease activities and soil catalase activities significantly increased by 0.65～3.27 times, 0.45～0.04 times and 0.08～1.19 times compared to without compost. And no significant was observed on the soil sucrose activities and the soil neutral phosphatase after the compost application.
|
PDF Full Text Request