畜禽粪便有机肥中重金属在水稻土中生物有效性动态变化

通过土壤淹水培养试验和土壤淹水培养不同时间后同时开始的水稻生物盆栽试验,研究不同畜禽粪便有机肥中Cu、Zn、Cd、Pb在水稻土中生物有效性动态变化以及与等量重金属无机盐的差异,明确不同畜禽粪便有机肥中不同重金属生物有效性差异及动态变化规律.结果表明,水稻土施入畜禽粪便有机肥后30~60 d内,畜禽粪便有机肥处理土壤溶液中重金属含量显著低于等量重金属无机盐处理,重金属无机盐处理土壤溶液中Cu、Zn、Cd、Pb的含量分别是鸡粪处理的2.4倍、3.1倍、3.9倍和327.3倍,分别是猪粪处理的2.0倍、2.2倍、15.6倍和4.0倍.60d后畜禽粪便有机肥处理和对应等量重金属无机盐处理土壤溶液中Cu、Zn、Cd、Pb的含量变的无差异.不同施用时间的畜禽粪粪便有机肥处理水稻体内Cu、Zn、Pb含量均显著低于对应的等量重金属无机盐处理,施用畜禽粪肥处理降低了土壤中Cu的生物有效性.畜禽粪便有机肥中重金属的生物有效性随施用后不同时间的变化呈现先升高后降低再升高规律,在施用后2个月时畜禽粪便有机肥中重金属的生物有效性最低,只相当于对应的等量重金属无机盐的13.0%~30.0%.

Bioavailability dynamics of heavy metals in manure and their effect on uptake of rice

Bioavailability dynamics of Cu, Zn, Cd and Pb in manure and the differences between different manures and inorganic salts were studied in different incubation time in paddy pot experiments. Results indicated that the amount of heavy metals in soil solution of inorganic salt treatments were significantly higher than the corresponding treatments amended with manure within 30~60 days. For chicken manure treatment, the concentrations of Cu, Zn, Cd and Pb in soil solution of inorganic salts treatment were 2.4, 3.1, 3.9 and 327.3 times the manure treatment during incubation, respectively. For swine manure treatment, concentrations of Cu, Zn, Cd and Pb in soil solution of inorganic salt treatment were 2.0, 2.2, 15.6 and 4.0 times the swine manure treatment during incubation, respectively. There were no significant differences between inorganic salts treatment and manure treatment after 60 days. Concentrations of Cu, Zn and Pb in rice of inorganic salt treatment were significantly higher than the corresponding treatments amended with manure. The bioavailability of major heavy metals in manure was less than that in salts. Application of organic manure reduced the bioavailability of Cu in soil. It was found that concentrations of heavy metals in plant increased first and then decreased, and finally increased again with the incubation time. The concentration reduced to minimum in the organic fertilization treatment at 2 months of treatment, and it was only about 13.0%~30.0% of inorganic salt treatment.