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| Mechanisms of underpinning the dicyandiamide-induced N2O emissions reduction in a fluvo-aquic soil after ammonium nitrogen fertilization |
| Received:April 17, 2021 |
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| KeyWord:nitrous oxide;dicyandiamide;nitrite nitrogen;nitrifier denitrification |
| Author Name | Affiliation | E-mail | | MA Lan | Shandong Institute of Sericulture, Yantai 264002, China
State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China | | | LI Xiaobo | Engineering and Technology Research Center for Agricultural Land Pollution Integrated Prevention and Control of Guangdong Higher Education Institutes, College of Resources and Environment, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China | | | MA Shutan | School of Ecology and Environment, Anhui Normal University, Wuhu 241002, China | mast@ahnu.edu.cn |
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| Abstract: |
| This study explores the mechanisms underpinning the dicyandiamide(DCD)-reducing nitrous oxide(N2O) emissions. This was carried out using two aerobic incubation experiments to examine the effects of DCD on the production of N2O from NO2--N by adding DCD combined with NH4+-N or NO2--N. Then, the effects of NO2--N accumulation on N2O emissions was determined by adding different amounts of NO2--N. The results showed that DCD only inhibited N2O emissions during the oxidation of ammonium nitrogen(NH4+-N) and had no effect on N2O emissions during the reduction of NO2--N. DCD significantly inhibited the oxidation of NH4+-N and decreased the net nitrification rate at 7 d following incubation; however, the net nitrification rate increased significantly following the addition of DCD to NO2--N soil. Following 30 d of culture, DCD had no effect on the oxidation of NH4+-N and NO2--N. The addition of exogenous NO2--N significantly promoted N2O emissions, and these emission rates were significantly higher than those of the control treatment. Cumulative N2O emissions were significantly positively correlated with the NO2--N concentrations, whereas the cumulative CO2 emissions demonstrated the opposite relationship. These results indicate that DCD may eliminate the toxicity caused by the accumulation of NO2--N, although it is only effective in reducing N2O emissions during the oxidation of ammonia oxidation. Therefore, new inhibitors that restrict N2O production from NO2--N are urgently needed. |
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