不同稻作制对红壤性水稻土铜的化学行为的影响

Effects of Various Rice-based Cropping Systems on Chemical Behaviour of Copper in the Paddy Soils Reclaimed from Red Earth

以湘中地区的耕型第四纪红土红壤进行不同稻作制度长期定位试验，研究旱改水及不同稻作制对土壤铜的化学行为及有效性的影响。结果表明，红壤旱地改水田１０年后，土壤对铜的吸附能力显著增强，土壤有效铜含量也明显提高。三种稻作制比较，稻稻冬泡土壤对铜的吸附能力和土壤有效铜含量明显高于稻稻冬绿和稻稻冬油土壤。供试土壤铜主要以有机态铜、无定形铁态铜、晶形铁态铜和残留态铜四种形态存在。红壤旱土改水田后，有机态铜和无定形铁态铜明显增加，而晶形铁态铜和残留态铜则显著下降；稻稻冬泡土壤的有机态铜和无定形铁态铜明显高于稻稻冬绿和稻稻冬油土壤；无定形铁态铜和有机态铜与土壤有效铜呈极显著线性正相关，是供试土壤有效铜的主要来源。

To study effects of red soils being reclaimed into flooded paddy soils and various rice-based cropping systems on chemical behaviour of Cu in the soils, a long term fixed -locution experiment has been carried out with the cultivated red soil derived from Ouarternary Red Clay for 10 years .The results obtained showed that the ability of adsorbing Cu by the soils was strengthened significantly after the red soil being reclaimed into flooded paddy soils ,and meanwhile the available Cu in the soils also increased greatly. When comparing them among 3 rice-based cropping systems, the adsorbing ability for Cu by soil and available Cu in the soils by the treatment of early rice -late rice-flooded in winter are much higher than that by the treatments of early rice-late rice -green manure in winter and early rice-late rice-rape in winter .Cu in the tested soils exists mainly as organic-bound Cu, amorphous Fe oxides-bound Cu,crystalline Fe oxides -bound Cu and the residual Cu. Of which, organic-bound Cu and amorphous Fe oxides -bound Cu in the soils increased significantly,while crystalline Fe oxides-bound Cu and the residual Cu decreased profoundly after red soil being reclaimed into flooded paddy soils .Also ,organic-bound Cu and amorphous Fe oxides-bound Cu in the soils by the treatment of early rice-late rice -flooded in winter are much higher than that by the treatments of early rice -late rice -green manure in winter and early rice -late rice-rape in winter .Organic-bound Cu and amorphous Fe oxides-bound Cu are positively correlated with available Cu in the tested soils at the level of P 0.01 significantly, and are the main sources of available Cu in the tested soils .