有机物料对稻作与非稻作土壤外源镉形态的影响研究

试验研究稻草、紫云英对稻作土壤和非稻作土壤中外源Cd形态及其变化的影响结果表明 ,稻草、紫云英显著降低培养 30d和培养 90d后非稻作土壤中交换态Cd含量。强烈还原条件下形成的硫化镉沉淀是稳定非稻作土壤交换态Cd含量的重要机制。稻草和紫云英对稻作土壤中外源Cd形态转化的影响不同 ,培养 30d后稻草和紫云英提高稻作土壤中氧化锰结合态和紧有机质结合态Cd含量 ,降低交换态Cd含量 ,其作用随时间的推移 ,氧化锰结合态Cd和紧有机质结合态Cd被释放出来并向交换态Cd转化 ,使交换态Cd含量提高。

Effects of organic matter on the forms of added Cd and its dynamic transformation in soil with or without growth of rice

The effects of rice straw and Chinese milk vetch on the forms of added Cd and it's dynamic transformation in soil with or without growth of rice were studied. The results show that rice straw and Chinese milk vecth can significantly reduce Ex(exchangeable)-Cd content in the soil without growth of rice. The formation of CdS under extremely low Eh condition is the important mechanism for Ex-Cd content, while the influences of rice straw and Chinese milk vetch on the forms of added Cd and it's dynamic transformation are apparently different. After one-month incubation, rice straw and Chinese milk vecth can decrease Ex-Cd content and increase the Sob(strong organic bound)-Cd and Mn(Mn oxide bound)-Cd contents in the soil with growth of rice. With the elapsing of time, Mn-Cd and Sob-Cd are released and transformed into Ex-Cd.