文献类型：期刊文献

英文题名：Forest soil respiration showed a saturation threshold in response to increasing nitrogen deposition: Evidence from a mesocosm experiment

作者：Li, Renshan[1,2] Han, Xinkuan[2] Bai, Yanfeng[3] Zhang, Fangfang[2] Sun, Honggang[4] Zhang, Weidong[1,5] Yang, Qingpeng[1,5] Wang, Silong[1,5]

第一作者：Li, Renshan

机构：[1] Huitong Experimental Station of Forest Ecology, CAS Key Laboratory of Forest Ecology and Silviculture, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China; [2] College of life Science, Luoyang Normal University, Luoyang, 471934, China; [3] Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China; [4] Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou, 311400, China; [5] Huitong National Research Station of Forest Ecosystem, Huitong, 418307, China

年份：2025

卷号：458

外文期刊名：Geoderma

收录：EI(收录号：20251918367222);Scopus(收录号：2-s2.0-105004230312)

语种：英文

外文关键词：Reforestation

摘要：Whether there is a N saturation threshold for the response of soil respiration (Rs) to increasing nitrogen (N) deposition remains unclear in forest ecosystems. In this work, a simulated N deposition experiment involving five levels of N addition (0 to 44.8 g N m?2 yr?1) was performed in a mesocosm experiment platform with young Chinese fir (Cunninghamia lanceolata) trees planted on it. Rs and its autotrophic (Ra) and heterotrophic (Rh) components were measured for four years, and the N saturation threshold was estimated using a quadratic-plus-plateau model. With increasing rate of N addition, Rs and Ra first increased dramatically until the critical N addition rate of 12.2 and 13.6 g N m?2 yr?1, respectively, and then leveled off. A similar non-linear increase in tree growth was also detected with N addition. In contrast, Rh continued to decrease as N addition increases, primarily a consequence of the N-increased recalcitrance of soil organic C, as evidenced by the decreased gram-negative bacteria biomass coupled with increased polyphenol oxidase activity. Our results indicated (1) that there was a N saturation threshold for the soil respiration, before which respiration rate increased with N addition and such an increase vanished thereafter; and (2) that the N saturation threshold of soil respiration was driven by autotrophic rather than heterotrophic respiration. This study advanced our understanding of the response of forest carbon cycle to growing N deposition. ? 2025