施用有机物料对污染土壤水溶性有机物和铜活性的动态影响

采用黑麦草盆栽研究施用绿肥、污泥和猪粪后，对Cu污染土壤水溶性有机物(DOM)和土壤Cu环境行为动态的影响．施用有机物料后土壤DOM含量比对照增加0.4—7.5倍，尤以绿肥和猪粪最明显．但随时间延长DOM降解明显，尤其在第一周内．污染土壤中水溶性Cu浓度随DOM的降解而相应减少研究发现，施用污泥有利于降低污染土壤中水溶性Cu浓度和黑麦草对Cu的吸收量，这是污泥固相有机质对Cu吸持使其活性降低和污泥DOM使Cu活性提高二者综合作用的结果．与此相反，施用绿肥和猪粪后，黑麦草体内的Cu含量却明显提高，其中潮土上提高1．4～2．1倍，红壤上提高1．4-1．6倍．因此．施用有机物料改良重金属污染地需格外谨慎。

The dynamics of dissolved organic matter and associated water-soluble Cu in two Cu-contaminated soils amended with various organic matters

The changes of dissolved organic matter (DOM) and the associated Cu in Cu contaminated acidic and calcareous soils amended with green manure (Vicia faba L.), pig manure and sewage sludge were studied by pot experiment with ryegrass to explore organic wastes derived DOM effect on soil Cu dissolution and bioavailability. As compared to control without addition of organic wastes, the concentration of DOM in the organic wastes treated soils increased drastically by 0.4-7.5 folds in the initial phase, depending on organic wastes origins. The green manure treated soils exhibited the highest DOM level followed by the pig manure amended soil. However, DOM concentration in the treated soils reduced markedly as time elapsed due to DOM biodegradation, especially in the first week after the organic wastes application. The DOM decomposition rates of the soil treated with green manure, pig manure and sewage sludge were 65%,37.8% and 27%,respectively. It was found that DOM enhanced Cu dissolution greatly in two Cu contaminated soils amended with green manure and pig manure. In the initial application phase, water soluble Cu concentration were 3.6-5 times and 0 6 times higher in the green manure and pig manure treated soils than that in the control, The soluble Cu concentration was reduced with the decrease of DOM in the soils, exhibiting an obvious positive linear correlation. However, difference in the soluble Cu concentration between the sewage sludge treated soil and the control was not observed. Furthermore, copper uptake by ryegrass increased by 1.4-2.1 times in Cu contaminated calcareous soil and 1.4-1.6 times in Cu contaminated acidic soil due to the application of green manure and pig manure. On the contrast, the incorporation of sewage sludge into two tested soils resulted in the decrease of Cu uptake by ryegrass.