淹水对湖南3种典型水稻土镉的形态分级影响

Morphological Classification Effect of Cadmium of Waterlogging on 3 Typical Paddy Soils in Hunan

以湖南外源镉(约1.0 mg/kg)污染的3种典型水稻土即红黄泥、河沙泥和灰泥为研究对象,通过淹水培养试验,研究了淹水前后土壤镉的各级形态变化。结果表明,淹水前,红黄泥田镉主要赋存形态为交换态(35.42%)、有机结合态(31.42%)和残渣态(28.08%);河沙泥田以残渣态为主(41.24%),其次是交换态(29.12%)和有机结合态(26.17%);灰泥田主要形态为有机结合态(68.78%)。淹水后,3种水稻土总体上呈现出交换态镉含量下降,而残渣态镉等升高的规律,交换态镉降幅表现为河沙泥田(60.00%)>红黄泥田(45.71%)>灰泥田(35.29%),残渣态镉增幅为灰泥田(142.86%)>河沙泥田(58.00%)>红黄泥田(42.86%),其他形态镉变化不明显。

Selected three typical paddy soil that reddish clayey soil, river sand mud and plaster polluted by exogenous cadmiumin Hunan as research object, studied the changes of each level of cadmium forms in soil before and after waterlogging through water logged incubation test. The results showed that before waterlogging, the main form of cadmium in reddish clayey soil was exchange form（35.42%）, organic bound form（31.42%） and residual form（28.08%）; the residue form was the main（41.24%）in river sand mud, the second was the exchange form（29.12%） and the organic bound form（26.17%）; The main form of plaster field as organic bound form（68.78%）. After waterlogging, all three kind of paddy soil showed decline in content of the exchange form cadmium, and rise in residual form cadmium, the exchange form cadmium declined performance wasriver sand mud field（60.00%） reddish clayey soil field（45.71%） plaster field（35.29%）,the rise performance of residual form cadmium was plaster field（142.86%） river sand mud field（58.00%） reddish clayey soil field（42.86%）. Other morphological changes of cadmium were not obvious.