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| Effect of dissolved organic matter from different sources on arsenic methylation in paddy soils |
| Received:October 07, 2019 |
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| KeyWord:pig manure DOM;organic arsenic;arsM;16S rRNA;soil pH |
| Author Name | Affiliation | E-mail | | TIAN Teng | School of Geographic and Environmental Sciences, Guizhou Normal University, Guiyang 550001, China
Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Key Laboratory of Agro-Environment, Ministry of Agriculture and Rural Affairs, Beijing 100081, China | | | YAN Meng-meng | Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Key Laboratory of Agro-Environment, Ministry of Agriculture and Rural Affairs, Beijing 100081, China | | | ZENG Xi-bai | Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Key Laboratory of Agro-Environment, Ministry of Agriculture and Rural Affairs, Beijing 100081, China | | | WANG Ji | School of Geographic and Environmental Sciences, Guizhou Normal University, Guiyang 550001, China | | | BAI Ling-yu | Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Key Laboratory of Agro-Environment, Ministry of Agriculture and Rural Affairs, Beijing 100081, China | | | WU Cui-xia | Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Key Laboratory of Agro-Environment, Ministry of Agriculture and Rural Affairs, Beijing 100081, China | | | SU Shi-ming | Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Key Laboratory of Agro-Environment, Ministry of Agriculture and Rural Affairs, Beijing 100081, China | sushiming@caas.cn |
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| Abstract: |
| Culture experiment using centrifuge tubes loaded with arsenic(As)-contaminated paddy soils from realgar mining area of Shimen County of Hunan Province was conducted to study the effect of dissolved organic matter(DOM)from different sources, such as from pig manure, cow dung, chicken manure, and rice straw, on arsenic methylation in paddy soils. The results indicated that DOM addition significantly changed the species of As in paddy soil, and the content of each As species increased under varying degrees with total organic carbon(TOC)concentrations. When the TOC reached 320 mg·L-1 in soil solution, the content of methyl-As under the four treatments of DOM were 75.8%, 75.7%, 68.3%, and 61.8% of the total As content, respectively. A significantly positive correlation(P<0.01)between methyl-As contents and TOC concentration in soil solution was found. The As methylation in paddy soil was evidently accelerated after the addition of DOM. As methylation efficiency from high to low was in the order of pig manure DOM(0.016 1 μg·L-1), chicken manure DOM (0.014 7 μg·L-1), cow dung DOM(0.009 9 μg·L-1), and rice straw DOM(0.008 2 μg·L-1). When the TOC applied reached 320 mg·L-1 in the soil solution, the copy numbers of arsM in soil with DOM addition were all higher than these in control, and the highest number was found in pig manure DOM treatment with 3.36×109 copies·g-1 which was about 2.0 times higher than that in the control. The soil pH after addition of different DOM was from high to low in the order of rice straw, cow dung, chicken manure, and pig manure. The pH values increased with increase in TOC concentration. The soil electrical conductivity(EC)varied from high to low in the order of rice straw, chicken manure, cow dung, and pig manure. In conclusion, DOM from different sources can differentially affect As methylation efficiency in paddy soils. It is expected that reasonable application of organic fertilizer might reduce the occurrence of rice straighthead disease to some extent by reducing the content of methyl-As in paddy soils. |
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