Patterns and controlling factors of soil carbon sequestration in nitrogen-limited and -rich forests in China-a meta-analysis

Mbezele Junior Yannick Ngaba; Yves Uwiragiye; Jianbin Zhou

doi:10.7717/peerj.14694

Patterns and controlling factors of soil carbon sequestration in nitrogen-limited and -rich forests in China-a meta-analysis

PeerJ. 2023 Jan 18:11:e14694. doi: 10.7717/peerj.14694. eCollection 2023.

Authors

Mbezele Junior Yannick Ngaba^{1

2

3}, Yves Uwiragiye^{1

2

4}, Jianbin Zhou^{1

2}

Affiliations

¹ College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, China.
² Key Laboratory of Plant Nutrition and the Agri-Environment in Northwest China, Ministry of Agriculture, Yangling, Shaanxi, China.
³ College of Resources and Environment, Southwest University, Chongqing, China.
⁴ University of Technology and Arts of Byumba, Byumba, Rwanda.

Abstract

Soil organic carbon (SOC) management has the potential to contribute to climate change mitigation by reducing atmospheric carbon dioxide (CO₂). Understanding the changes in forest nitrogen (N) deposition rates has important implications for C sequestration. We explored the effects of N enrichment on soil carbon sequestration in nitrogen-limited and nitrogen-rich Chinese forests and their controlling factors. Our findings reveal that N inputs enhanced net soil C sequestration by 5.52-18.46 kg C kg^-1 N, with greater impacts in temperate forests (8.37-13.68 kg C kg^-1 N), the use of NH₄NO₃ fertilizer (7.78 kg Ckg^-1 N) at low N levels (<30 kg Ckg^-1 N; 9.14 kg Ckg^-1 N), and in a short period (<3 years; 12.95 kg C kg^-1 N). The nitrogen use efficiency (NUE) varied between 0.24 and 13.3 (kg C kg^-1 N) depending on the forest type and was significantly controlled by rainfall, fertilizer, and carbon-nitrogen ratio rates. Besides, N enrichment increased SOC concentration by an average of 7% and 2% for tropical and subtropical forests, respectively. Although soil carbon sequestration was higher in the topsoil compared to the subsoil, the relative influence indicated that nitrogen availability strongly impacts the SOC, followed by dissolved organic carbon concentration and mean annual precipitation. This study highlights the critical role of soil NUE processes in promoting soil C accumulation in a forest ecosystem.

Keywords: Belowground soil C processes; Carbon sequestration; Nitrogen addition; Nitrogen use efficiency.

Publication types

Meta-Analysis

MeSH terms

Carbon / analysis
Carbon Sequestration*
China
Ecosystem*
Fertilizers / analysis
Forests
Nitrogen / analysis
Soil

Substances

Soil
Nitrogen
Carbon
Fertilizers

Grants and funding

This work was supported by the National Natural Science Foundation of China (No. 41671295), the National Key R & D Program of China (No. 2017YFD0200106), and the 111 Project (No. B12007). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.