关中平原畜禽粪便重金属农用风险估算

The agricultural pollution risk estimation of livestock manures on heavy metals in Guanzhong plain

通过在关中平原畜禽养殖集中的县区采集畜禽粪便和饲料样品,测定其中Cr、Cu、Pb、Zn等重金属元素含量,以评估施用畜禽粪便造成的土壤重金属累积速率和安全使用年限.结果表明,牛粪、鸡粪、猪粪样品中Cr超标率分别为7.69%,4.35%和8.00%,而猪粪中Cu、Zn超标率分别达到76.00%和8.00%.饲料样品中Cu、Zn含量高于Cr、Pb含量,且与畜禽粪便Cu、Zn含量呈极显著正相关关系结合主成分分析可知,畜禽粪便中Cu、Zn主要来源于饲料.形态分析结果显示,畜禽粪便中Cu,Zn的有效性很高,尤其是鸡粪中Cu、Zn的有效态含量最高若畜禽粪便施用量保持在当前水平,则施用畜禽粪便24.4~131.0年和69.7~91.9年后,大棚土壤中Cu、Zn含量即可从土壤背景值分别达到安全临界值,因此,畜禽粪便农用时不仅要控制其施用量,还应适当减少饲料中Cu、Zn添加量.

The concentrations of Cr,Cu,Pb,Zn in livestock manures and feeds from livestock farm concentrated regions in Guanzhong Plain were determined to evaluate the heavy metal accumulation rates and the manure safe service period.The results indicated that 7.69%,4.35%and 8.00%of cattle,chicken and pig manure samples were out of limit on Cr,respectively,moreover,76.00% and 8.00%samples of pig manure exceeded the limits of Cu and Zn,respectively.The concentrations of Cu and Zn in livestock feeds were more than those of Cr and Pb,and had a significantly positive correlation between those in manure.The principal component analysis results showed that the Cu and Zn in manure primarily derived from livestock feeds.The morphological analysis of Cu and Zn showed that the availability of Cu and Zn in manure were very high,especially in chicken manure.The concentrations of Cu and Zn in greenhouse soil would exceed the safe limits from soil background values in 24.4~131.0 and 69.7~91.9years under the manure fertilization situation,respectively.As a result,it＇s urgent to control the manure overuse in agriculture and reduce the addition of Cu and Zn in livestock feeds.