畜禽粪便有机肥中Cu、Zn在水稻土中的有效性动态变化和形态归趋

通过温室土壤培养试验,研究了不同畜禽粪便有机肥中Cu、Zn在水稻土中有效性动态变化过程和形态归趋,为科学评价畜禽粪便有机肥中重金属进入稻田后的生态风险提供理论依据.试验结果表明,施用畜禽粪便有机肥12个月后,水稻土p H提高了0.4~0.9.施用鸡粪降低了水稻土中有效态Cu含量,而猪粪的施用增加了水稻土中有效态Cu含量.水稻土中有效态Zn含量随畜禽粪便有机肥施用量的增加而增加.与重金属无机盐相比,鸡粪处理中Cu的有效性低于等量无机盐处理,猪粪处理中Cu、Zn和鸡粪处理中Zn的有效性与等量无机盐处理相同.形态归趋过程研究结果表明,畜禽粪便有机肥带入到水稻土中Cu、Zn的量较低时,Cu在有机质结合态中有显著的积累,Zn则在碳酸盐结合态中有显著的积累;带入的Cu、Zn的量较高时,Cu、Zn在各个形态中均有积累;无机盐带入水稻土的Cu、Zn在交换态、碳酸盐结合态、铁锰氧化物结合态和有机结合态中均有积累.畜禽粪便有机肥带入的Cu、Zn积累在有机结合态中的量与等量无机盐处理无显著差异.培养12个月时,有机肥处理的交换态Cu含量均显著高于等量无机盐处理,表明畜禽粪便有机肥中Cu的潜在有效性更高.

Dynamics of bioavailability and form change of copper and zinc in paddy soil with livestock and poultry manures

Soil incubation experiment was conducted to investigate the dynamics of bioavailability and form change of Cu and Zn in manure applied to soil. The results showed that, the pH value of paddy soil with livestock and poultry manure increased by 0.4~0.9 units after 12 months of livestock and poultry manure application. The contents of available Cu in paddy soil decreased after chicken manures application, but increased after pig manures application. The availability of Zn increased with increasing doses of livestock and poultry manure. The contents of available Cu in paddy soil that treated with chicken manures were lower than those with the equivalent inorganic Cu, while the contents of available Cu and Zn under pig manures treatment and available Zn under chicken manures treatment had no significant difference with equivalent inorganic treatment. Form change analysis showed that, when the contents of Cu and Zn in livestock and poultry manure were low, the main form of Cu accumulated in paddy soil was organic, while that of Zn was carbonate. However, when the contents were high, Cu and Zn could accumulate in all kinds of forms. There was no significant deference between the treatments of manures and inorganic salts in the contents of Cu and Zn. After 12 months of livestock and poultry manure application, the content of exchangeable Cu were higher than that of inorganic salt treatments, which indicated that the potential availability of Cu in livestock and poultry manures was higher than that in inorganic salt. The research results will provide a theory basis for a scientific ecological risk assessment regarding heavy metals into paddy soil.