耕作层中重金属Cd形态分布规律及植物有效性研究

就外源重金属Ｃｄ在土壤中的存在形态，影响因素以及黑麦草对土壤Ｃｄ的吸收进行了研究。结果表明，土壤对Ｃｄ的吸持率为红壤〈水稻〈潮土，与土壤ｐＨ值明显呈相关，土壤吸持Ｃｄ中，红壤以交换态为主，水稻土以络合态为主，潮土则以残渣态为主；黑麦草吸收的Ｃｄ与土壤ｐＨ值呈显的负相关、植物有效态Ｃｄ源主要来自交换态Ｃｄ和松结有机态Ｃｄ。

Chemical Form Distribution and Plant Availability of Cd in Plough Horizon

The chemical form distribution of external Cd in soil and its influencing factors, as well as the uptake of soil Cd in ryegrass are investigated in this paper. Results show that the red soil has the strongest retention rate of Cd, followed by the paddy soil, and then the chao soil. The Cd retention rate of soil is positively related with the soil pH. The chemical form fractions for Cd adsorbed by soils show that exchangeable Cd is the main form in red soil, complexed Cd in paddy soil and residual bonnd Cd in chao soil. The results also indicate that the amount of Cd accumulated by ryegrass is negatively related to the pH of soil, the plant available sources of Cd come mainly from the soil exchangeable Cd as well as Cd weakly bound to organic matters.