title: Dissimilatory Nitrate Reduction Processes in Typical Chinese Paddy Soils: Rates, Relative Contributions, and Influencing Factors.
abstract: Using soil slurry-based (15)N tracer combined with N2/Ar technique, the potential rates of denitrification, anaerobic ammonium oxidation (anammox), and dissimilatory nitrate reduction to ammonium (DNRA), and their respective contributions to total nitrate reduction were investigated in 11 typical paddy soils across China. The measured rates of denitrification, anammox, and DNRA varied from 2.37 to 8.31 nmol N g(-1) h(-1), 0.15 to 0.77 nmol N g(-1) h(-1) and 0.03 to 0.54 nmol N g(-1) h(-1), respectively. The denitrification and anammox rates were significantly correlated with the soil organic carbon content, nitrate concentration, and the abundance of nosZ genes. The DNRA rates were significantly correlated with the soil C/N, extractable organic carbon (EOC)/NO3(-) ratio, and sulfate concentration. Denitrification was the dominant pathway (76.75-92.47%), and anammox (4.48-9.23%) and DNRA (0.54-17.63%) also contributed substantially to total nitrate reduction. The N loss or N conservation attributed to anammox and DNRA was 4.06-21.24 and 0.89-15.01 g N m(-2) y(-1), respectively. This study reports the first simultaneous investigation of the dissimilatory nitrate reduction processes in paddy soils, highlighting that anammox and DNRA play important roles in removing nitrate and should be considered when evaluating N transformation processes in paddy fields.
authors: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences , Nanjing 210008, China.
authors: Jun
authors: J
authors: Shan
authors: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences , Nanjing 210008, China.
authors: Xu
authors: X
authors: Zhao
authors: Key Laboratory of Agro-ecological Processes in Subtropical Regions and Taoyuan Agro-ecosystem Research Station, Soil Molecular Ecology Section, Institute of Subtropical Agriculture, Chinese Academy of Sciences , Changsha 410125, China.
authors: Rong
authors: R
authors: Sheng
authors: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences , Nanjing 210008, China.
authors: Yongqiu
authors: Y
authors: Xia
authors: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences , Nanjing 210008, China.
authors: Chaopu
authors: C
authors: Ti
authors: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences , Nanjing 210008, China.|University of Chinese Academy of Sciences , Beijing 100049, China.
authors: Xiaofei
authors: X
authors: Quan
authors: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences , Nanjing 210008, China.|University of Chinese Academy of Sciences , Beijing 100049, China.
authors: Shuwei
authors: S
authors: Wang
authors: Key Laboratory of Agro-ecological Processes in Subtropical Regions and Taoyuan Agro-ecosystem Research Station, Soil Molecular Ecology Section, Institute of Subtropical Agriculture, Chinese Academy of Sciences , Changsha 410125, China.
authors: Wenxue
authors: W
authors: Wei
authors: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences , Nanjing 210008, China.
authors: Xiaoyuan
authors: X
authors: Yan
mesh_terms: D064751:Ammonium Compounds / Q000378:metabolism; D058440:Denitrification; D009566:Nitrates; D009589:Nitrogen Oxides; D010084:Oxidation-Reduction; D012987:Soil
chemical_list: D064751:Ammonium Compounds; D009566:Nitrates; D009589:Nitrogen Oxides; D012987:Soil