肥料重金属含量状况及施肥对土壤和作物重金属富集的影响

本文对肥料中重金属的含量状况以及施肥对土壤和农作物重金属累积影响的研究进展进行了系统分析和总结。过磷酸钙中锌（Zn）、 铜（Cu）、 镉（Cd）、 铅（Pb）含量高于氮肥、 钾肥和三元复合肥，有机-无机复混肥料中的Pb含量高于其他化肥。有机肥如畜禽粪便、 污泥及其堆肥中的重金属含量高于化肥，猪粪中的Cu、 Zn、 砷（As）、 Cd含量明显高于其他有机废弃物，鸡粪中铬（Cr）含量高；污泥和垃圾堆肥中Pb或汞（Hg）含量高。商品有机肥Zn、 Pb和镍（Ni）含量高于堆肥，Hg含量高于畜禽粪便。多数研究表明，氮磷钾配施与不施肥相比土壤Cd和Pb含量增加，施用有机肥比不施肥提高土壤Cu、 Zn、 Pb、 Cd含量。施用化肥对农作物重金属富集的影响不明确，而施用有机肥可提高作物可食部位Cu、 Zn、 Cd、 Pb 的含量，影响大小与有机肥种类、 用量、 土壤类型和pH以及作物种类等有很大关系。在今后的研究中应着重以下几个方面, 1）典型种植体系下土壤重金属的投入/产出平衡； 2）不同种植体系下长期不同施肥措施对土壤重金属含量、 有效性影响的动态趋势； 3）典型种植体系和施肥措施下土壤对重金属的最高承载年限； 4）现有施肥措施下肥料中重金属的最高限量标准。

Heavy metals in fertilizers and effect of the fertilization on heavy metal accumulation in soils and crops

This paper systematically reviewed the status of heavy metal contents in chemical fertilizers and manures, and effects of the fertilizers application on heavy metal accumulation in soils and crops. The contents of zinc (Zn), copper (Cu), cadmium (Cd) and lead (Pb) in superphosphate are higher than those in nitrogen fertilizers, potash  and NPK compound fertilizers. The concentrations of Pb in organic-inorganic compound fertilizers are higher than those of other fertilizers. Generally, the heavy metal contents in organic manures such as livestock manure, compost of sewage sludge are higher than those of the chemical fertilizers. The concentrations of Cu, Zn, arsenic（As） and Cd in pig manure are higher than those of other organic wastes. Chicken manure has high chromium（Cr） concentration, sludge and compost of municipal wastes have high Pb or Hg concentrations. Commercial organic fertilizers have higher Zn, Pb and nickel (Ni) concentrations than those of composts of sludge and municipal wastes, and have higher mercury（Hg） contents than those of animal manures. Most research results show that applications of NPK increase soil Cd and Pb contents, and organic fertilizer increase soil Cu, Zn, Pb and Cd contents compared with the control. The effect of chemical fertilizer applications on heavy metal accumulation in crops is not clear, while most studies show that applications of organic fertilizers could improve Cu, Zn, Cd and Pb concentrations in edible parts of crops, and the affection depends on type/amount of organic fertilizers, soil type, soil pH and crop varieties. Future research should focus on the following aspects:   1) Input/output balance of heavy metals in typical soil-plant systems; 2) Dynamics of heavy metal contents and availabilities in soils affected by long-term application of fertilizers; 3) The maximum bearing years for heavy metals under typical fertilizer application patterns in typical planting system;  4) The maximum permissible concentrations for heavy metals in applied fertilizers under current nutrient management practices.