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| Denitrification capacity and its influencing factors in typical ditches and ponds in the Dongting Lake area，China |
| Received:July 27, 2022 |
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| KeyWord:denitrification rate;ditch and pond;nitrogen removal capacity;non-point source pollution |
| Author Name | Affiliation | E-mail | | LONG Guangli | College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China | | | YAN Xing | Nanjing Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China | | | XIA Yongqiu | Nanjing Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China | | | LIU Xin | College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China | | | WEN Jiong | Yueyang Academy of Agricultural Sciences, Yueyang 414000, China | | | PENG Zhi | Yueyang Academy of Agricultural Sciences, Yueyang 414000, China | | | RONG Xiangmin | College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China | rongxm2005@163.com |
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| Abstract: |
| To investigate the denitrification pattern of denitrification in typical ditches and ponds in Dongting Lake area, based on a nearin situ incubation method combined with membrane inlet mass spectrometry, this study investigated the patterns of denitrification rates in ditches and ponds wetlands in the Dongting Lake basin and the influencing factors in the overlying water and sediments from September 2020 to August 2021. The results showed that there was significant spatial and temporal heterogeneity in denitrification rates in the ditches and ponds of Dongting Lake. Denitrification rates ranged from 22.10 μmol·m–2·h–1 to 238.02 μmol·m–2·h–1, with a mean value of 91.12 μmol·m–2·h–1. The denitrification rates in spring and summer were higher than those in autumn and winter. The types of ditches and ponds also showed significant differences in denitrification rates, with the highest rate in agricultural ditches, followed by branch ditches, ponds, main ditches, vegetated ditches, and non-vegetated ditches. Partial least squares regression（PLSR）analysis showed that nitrate nitrogen （NO–3-N）concentration, dissolved organic carbon（DOC）in the water column, and sediment DOC significantly affected denitrification rates（P< 0.05）, with nitrate nitrogen concentration the most significant limiting factor for denitrification. The ditch and pond wetlands can remove 33.44% of nitrogen load in the study region, significantly reducing nitrogen input to downstream waters, thereby playing an important role in mitigating non-point source pollution in the Dongting Lake watershed. |
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