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

通信作者：Zhang, WD[1];Yang, QP[1]

机构：[1]Chinese Acad Sci, Inst Appl Ecol, CAS Key Lab Forest Ecol & Silviculture, Huitong Expt Stn Forest Ecol, Shenyang 110016, Peoples R China;[2]Luoyang Normal Univ, Coll life Sci, Luoyang 471934, Peoples R China;[3]Chinese Acad Forestry, Res Inst Forestry, Beijing 100091, Peoples R China;[4]Chinese Acad Forestry, Inst Subtrop Forestry, Hangzhou 311400, Peoples R China;[5]Huitong Natl Res Stn Forest Ecosyst, Huaihua 418307, Peoples R 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);WOS:【SCI-EXPANDED(收录号:WOS:001494519100001)】；

基金：This work was supported by the National Natural Science Foundation of China (Grant Nos. U22A20612 and 32192434) , the National Key Research and Development Program of China (Grant No. 2022YFF1303003) , the Science and technology innovation Program of Hunan Province (2024RC4029) , Henan Province Science and Technology Breakthrough Project (242102320148) , and Natural Science Foundation of Henan Province (202300410287) . We also thank Xiuyong Zhang, Xiaojun Yu, Ke Huang, and Yankuan Zhang for their invaluable assistance in the laboratory and the field work.

语种：英文

外文关键词：Soil CO 2 efflux; Carbon cycle; Nitrogen cycle; Nitrogen treatment; Climate change

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.