Nitrogen deposition accelerates soil carbon sequestration in tropical forests
X. L. Lu, Peter M. Vitousek, Qinggong Mao, Frank S. Gilliam, Yiqi Luo, Benjamin L. Turner, Guoyi Zhou, Jiangming Mo
Abstract
Significance Forest soil carbon (C) storage plays a central role in sequestrating atmospheric CO 2 on timescales from centuries to millennia. However, our current understanding of soil C sequestration in response to N deposition mainly focuses on mid-to-high latitudes in the Northern Hemisphere, where N supply typically constrains forest growth. We lack data about changes in soil C stocks in tropical forests, where most ecosystems are N-rich or N-saturated. Using more than a decade of continuous N addition experiment and a meta-analysis, we found that excess N deposition can significantly increase soil C in N-rich tropical forests. However, enhanced C sequestration in tropical soils is not a good reason to justify excess N emissions to the atmosphere.