Nitrification activities and N mineralization in paddy soils are insensitive to oxygen concentration |
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| Authors: | Yanju Yang Jinbo Zhang |
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| Affiliation: | 1. School of Geography Science, Nanjing Normal University, Nanjing, People's Republic of China;2. Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, Nanjing, People's Republic of China;3. Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing, People's Republic of China;4. Key Laboratory of Virtual Geographical Environment (VGE), Ministry of Education, Nanjing Normal University, Nanjing, People's Republic of China |
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| Abstract: | Oxygen concentration is considered to be the most important factor influencing nitrification and mineralization rates in agricultural soils. However, the sensitivities of nitrification and N mineralization in paddy soils to oxygen concentrations are not well known. We examined nitrification activities and N mineralization rates of six paddy soils with pH ranging from 5.23 to 7.83 and incubated at 25°C and 60% water-holding capacity in laboratory after ammonium was added at concentrations of 10, 30 and 50?mg?N?kg?1 of soil and the headspace gases were replaced with stock gases whose oxygen concentrations were 20%, 10% and 2%, respectively. The tested paddy soils had a very wide range of nitrification activities so that the nitrate ratio in inorganic N varied from >?95% after 1 day incubation to?
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| Keywords: | Ammonium mineralization rates nitrification activities oxygen paddy soils soil pH |
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