【摘要】 本试验用逐级提取方法，研究了外源铬进入土壤后的形态转化，结果表明：添加到土壤小的Ｃｒ（Ⅵ）很快还以为Ｃｒ（Ⅲ）而失去其活动性，水溶态和交换态铬含量在培育６周后已恢复到对照水平，添加的Ｃｒ（Ⅲ）很快被土壤吸附和沉淀而固定，难以被Ｈ＿２Ｏ和ＮＨ＿４Ａｃ提取。添加的有机结合态铬能显著提高土壤中水溶态和交换态铬含量，并能在较长时间内稳定存在于土壤中，添加污泥形式的铬进入土壤主要以残渣态、沉淀态和有机紧结合态铬为主。更多还原

【Abstract】 Abstract Cr（Ⅵ）add to soil was rapidly reduced into Cr（Ⅲ）and then convertedinto less mobile precipitation and organic-bound Cr。Cr（Ⅲ）add to soils wasrapidly absorbed and precipitated,and then converted gradually into organic-bound and residual Cr as incubation time increased。Treatment with Cr（Ⅲ）raised Cr（Ⅲ）solubility in soils following the order of EPTA-Cr>citric-Cr>fulvic-Cr>humic-Cr. Organic complexed Cr（Ⅲ）might exist in a long per-iod in soil solution, because it could not easily adsorbed and precipitatedby soils.Sludge-amended soil contained very little watersoluble and NH₄Acextractable Cr. Residues,precipitation and organic-bound Cr predominatedin the soil, together accounting for about 99%or even more of the totalCr. In the incubation process, residual Cr became Organic-bound and preci-pitated gradually.更多还原