title: Extreme rainfall and snowfall alter responses of soil respiration to nitrogen fertilization: a 3-year field experiment.
abstract: Extreme precipitation is predicted to be more frequent and intense accompanying global warming and may have profound impacts on soil respiration (Rs) and its components, that is, autotrophic (Ra) and heterotrophic (Rh) respiration. However, how natural extreme rainfall or snowfall events affect these fluxes are still lacking, especially under nitrogen (N) fertilization. In this study, extreme rainfall and snowfall events occurred during a 3-year field experiment, allowing us to examine their effects on the response of Rs, Rh, and Ra to N supply. In normal rainfall years of 2011/2012 and 2012/2013, N fertilization significantly stimulated Rs by 23.9% and 10.9%, respectively. This stimulation was mainly due to the increase of Ra because of N-induced increase in plant biomass. In the record wet year of 2013/2014, however, Rs was independent on N supply because of the inhibition effect of the extreme rainfall event. Compared with those in other years, Rh and Ra were reduced by 36.8% and 59.1%, respectively, which were likely related to the anoxic stress on soil microbes and decreased photosynthates supply. Although N supply did not affect annual Rh, the response ratio (RR) of Rh flux to N fertilization decreased firstly during growing season, increased in nongrowing season and peaked during spring thaw in each year. Nongrowing season Rs and Rh contributed 5.5-16.4% to their annual fluxes and were higher in 2012/2013 than other years due to the extreme snowfall inducing higher soil moisture during spring thaw. The RR of nongrowing season Rs and Rh decreased in years with extreme snowfall or rainfall compared to those in normal years. Overall, our results highlight the significant effects of extreme precipitation on responses of Rs and its components to N fertilization, which should be incorporated into models to improve the prediction of carbon-climate feedbacks.
authors.affiliation: 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.forename: Zengming
authors.initials: Z
authors.lastname: Chen
authors.affiliation: 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.forename: Yehong
authors.initials: Y
authors.lastname: Xu
authors.affiliation: School of Ecological and Environmental Sciences, East China Normal University, Shanghai, 200062, China.|Center for Global Change and Ecological Forecasting, East China Normal University, Shanghai, 200062, China.
authors.forename: Xuhui
authors.initials: X
authors.lastname: Zhou
authors.affiliation: The Ecosystems Center, Woods Hole, MA, 02543, USA.
authors.forename: Jianwu
authors.initials: J
authors.lastname: Tang
authors.affiliation: Department of Agricultural Soil Science, University of Göttingen, Büsgenweg 2, Göttingen, 37077, Germany.|Department of Soil Science of Temperate Ecosystems, University of Göttingen, Büsgenweg 2, Göttingen, 37077, Germany.
authors.forename: Yakov
authors.initials: Y
authors.lastname: Kuzyakov
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China.
authors.forename: Hongyan
authors.initials: H
authors.lastname: Yu
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China.
authors.forename: Jianling
authors.initials: J
authors.lastname: Fan
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China.
authors.forename: Weixin
authors.identifier: 0000-0003-3610-7611
authors.initials: W
authors.lastname: Ding
mesh_terms: D000383:Agriculture; D052818:Autotrophic Processes; D002244:Carbon; D057486:Carbon Cycle; D005308:Fertilizers; D009584:Nitrogen; D058458:Nitrogen Cycle; D011891:Rain; D012987:Soil / Q000737:chemistry*
chemical_list: D005308:Fertilizers; D012987:Soil; D002244:Carbon; D009584:Nitrogen
keywords: autotrophic respiration; extreme precipitation; heterotrophic respiration; nitrogen fertilization; nongrowing season; soil respiration; soil waterlogging; spring thaw