摘要
以贵州万山汞矿区的汞污染稻田土为研究对象,采用盆栽模拟探究了小麦-水稻轮作情况下秸秆覆盖还田对土壤及小麦与水稻在重要生育期(出苗期、分蘖期、拔节期、扬花-灌浆期、乳熟-收获期)甲基汞累积的影响。结果表明:秸秆还田能提高土壤中甲基汞含量,且不同作物秸秆还田对土壤甲基汞及作物甲基汞的影响存在显著差别,其中,小麦秸秆还田后土壤甲基汞含量增加127.1%,水稻秸秆还田后土壤甲基汞含量增加25.1%,这可能缘于迥异的种植条件。同时,作物秸秆还田后小麦、水稻植株体内甲基汞含量也呈增加趋势,其中,小麦根部、地上部(茎叶)和籽粒甲基汞含量分别增加124.6%、79.2%和169%,水稻根部、地上部和籽粒甲基汞含量依次增加40.1%、61.7%和25.9%,表明作物甲基汞吸收累积量的上升可能主要源于土壤甲基汞含量的上升。因此,汞污染地区传统农艺措施中惯常采用的秸秆还田可能会显著增加人体甲基汞暴露风险,在汞污染地区推广作物秸秆还田措施时应持谨慎态度。
There is growing concern about methylmercury（Me Hg）accumulation in crop plants in Hg-contaminated areas. To investigate the possible influences of straw amendment on soil methylmercury levels and its accumulation in crop plants, mercury-contaminated paddy soil was collected from Wanshan mercury mine area and amended with 1%（W/W）crop straw（wheat or rice）in a wheat-rice rotation system. At different stages（e.g., seedling, tillering, jointing, flowering and harvesting）of plant growth, the soil and plant samples were collected and analyzed for Me Hg. The results show that straw amendment could lead to a substantial increases in Me Hg levels in both soils and plants. Soil Me Hg increased by 127.1% under wheat-straw amendment and 25.1% under rice-straw amendment, respectively. This was possibly due to the different planting conditions. Correspondingly, Me Hg levels in root, aboveground part and grain of wheat increased by 124.6%, 79.2%and 169%, respectively, compared to the control. Similarly, Me Hg levels in root, aboveground part and grain of rice increased by 40.1%,61.7% and 25.9%, respectively. Overall, there is a positive relationship between the crop plant Me Hg levels and soil Me Hg levels under wheat-rice rotation, indicating that straw amendment could increase soil Me Hg levels and subsequently the Me Hg accumulation in crops,which could enhance the potential risk of human exposure to Me Hg in mercury-contaminated areas. These results suggest that it should be cautious when promoting straw amendment in mercury-contaminated areas.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2016年第10期1931-1936,共6页
Journal of Agro-Environment Science
基金
贵州省教育厅项目(黔教合KY字2015-330)
贵州省山地环境气候研究所院士工作站项目(2014)4010
中央高校基本科研业务费资助项目(021114340125)
关键词
秸秆还田
稻田土壤
稻麦轮作
作物
甲基汞
straw return
paddy soil
wheat-rice rotation
crop
methylmercury
