长期施肥对褐土及玉米籽粒中Hg含量的影响

Effect of Long-term Fertilization on Hg Contents of Cinnamon and Corn Grain

针对土壤中重金属Hg污染的现状,为研究北方半湿润偏旱区褐土农田Hg元素的长期变化规律,对连续进行22年的氮磷化肥与有机肥配施试验0-40 cm农田土壤及2013年玉米籽粒中的Hg含量进行了测定,分析了长期施肥条件下褐土Hg元素的盈亏状况、年际变化和剖面特征及对玉米籽粒中Hg含量的影响。结果表明,不施肥处理的土壤Hg含量有所亏缺,其他施肥处理Hg含量均有盈余;随着施肥年限的增长,土壤Hg呈下降趋势,比基础土样降低了29.3%-74.2%;高量施肥均可能会引起表层Hg含量的向下迁移,导致20-40 cm土壤Hg含量升高。2013年不同施肥处理土壤Hg含量均未超过国家土壤环境质量二级标准;长期氮磷化肥与有机肥配施对处理间土壤Hg含量差异影响不显著;2013年玉米籽粒中Hg含量低于国家限量标准。长期氮磷化肥与有机肥配施未造成土壤Hg污染。

Based on the situation of Hg pollution in the soil,the change rule of Hg element in north sub-humid cinnamon of farmland were studied. The Hg content in the soil surface layer of 0-40 cm and in the corn grain in2013 of the experiment on 22-year application of nitrogen,phosphorus and organic fertilizers were determined,and the analysis of Hg content in corn grain in 2013,the balance and interannual and depth profile changes of Hg content in cinnamon soil under long-term fertilization were studied. The results showed that the soil Hg content of no fertilizer treatment decreased,others increased; With time running after fertilization the soil Hg content decreased29. 3%-74. 2% respectively as compared to the baseline levels; High fertilization may cause the rise of Hg content in soil layer of 20-40 cm. The content of Hg in soil tested in 2013 did not exceed the upper limits of the grade II criteria of the national standard for soil environment; Hg content between treatment in cinnamon soil was not significantly affected by the use of nitrogen,phosphorus and organic fertilizers. Hg content in corn grain analyzed in 2013 were below their respective threshold of the national food safety standard. Long-term nitrogen,phosphorus and organic fertilizers had no sign to show.