Depth-driven responses of microbial residual carbon to nitrogen addition approaches in a tropical forest: Canopy addition versus understory addition
Kuang, Luhui (South China Botanical Garden. Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems)
Mou, Zhijian (South China Botanical Garden. Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems)
Li, Yue (South China Botanical Garden. Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems)
Lu, Xiaofei (Nanjing University of Information Science & Technology. School of Environmental Science and Engineering)
Kuang, Yuanwen (South China Botanical Garden. Guangdong Provincial Key Laboratory of Applied Botany)
Wang, Jun (South China Botanical Garden. Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems)
Wang, Faming (South China Botanical Garden. Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems)
Cai, Xi'an (South China Botanical Garden. Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems)
Zhang, Wei (South China Botanical Garden. Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems)
Fu, Shenglei (Henan University. College of Environment and Planning)
Hui, Dafeng (Tennessee State University. Department of Biological Sciences)
Lambers, Hans (University of Western Australia. School of Biological Sciences)
Sardans i Galobart, Jordi (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Peñuelas, Josep (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Ren, Hai (South China Botanical Garden. Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems)
Liu, Zhanfeng (South China Botanical Garden. Guangdong Provincial Key Laboratory of Applied Botany)

Date:	2023
Abstract:	Canopies play an important role in nitrogen (N) redistribution in forest ecosystems, and ignoring the canopy's role might bias estimates of the ecological consequences of anthropogenic atmospheric N deposition. We investigated the effects of the approach of N addition (Canopy addition vs. Understory addition) and level of N addition (25 kg N ha−1yr−1 vs. 50 kg N ha−1yr−1) on microbial residual carbon (MRC) accumulation in topsoil and subsoil. We found that the response of MRC to both approach and level of N addition varied greatly with soil depth in a tropical forest over eight years of continuous N addition. Specifically, N addition enhanced the accumulation of fungal and total MRC and their contribution to soil organic C (SOC) pools in the topsoil, whereas it decreased the contribution of fungal and total MRC to SOC in the subsoil. The contrasting effects of N addition on MRC contribution at varying soil depths were associated with the distinct response of microbial residues production. Understory N addition showed overall greater effects on MRC accumulation than canopy N addition did. Our results suggest that the canopy plays an important role in buffering the impacts of anthropogenic atmospheric N deposition on soil C cycling in tropical forests. The depth-dependent response of microbial residues to N addition also highlights the urgent need for further studies of different response mechanisms at different soil depths.
Grants:	Agencia Estatal de Investigación PID2019-110521GB-I00 Agencia Estatal de Investigación PID2020-115770RB-I Agència de Gestió d'Ajuts Universitaris i de Recerca SGR/2017-1005
Note:	Altres ajuts: the Fundación Ramón Areces grant CIVP20A6621.
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades.
Language:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Subject:	Nitrogen addition ; Canopy nitrogen addition ; Understory nitrogen addition ; Microbial residual carbon ; Soil depth ; Tropical forest
Published in:	Journal of environmental management, Vol. 340 (August 2023) , art.118009, ISSN 1095-8630

DOI: 10.1016/j.jenvman.2023.118009

Available from: 2025-08-30 Postprint

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Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > CREAF (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Articles > Research articles
Articles > Published articles