Leaky nitrogen cycle in pristine African montane rainforest soil

Pristine African montane rainforests, such as Nyungwe National Park in Rwanda, exhibit a 'leaky' nitrogen (N) cycle characterized by high nitrate leaching losses despite being N-rich. This study, combining field monitoring and an in situ 15N labeling experiment, revealed that the soil N cycle in these forests is open, with mineralized N predominantly nitrified rather than immobilized. Gross immobilization accounted for only 37% of gross mineralization, while plant N uptake was dominated by ammonium (NH4+). These findings confirm similar dynamics observed in other tropical forests globally and provide critical evidence that humid tropical forests sustain bioavailable N loss, contributing to our understanding of soil N cycling in these ecosystems.

Rütting, T., Cizungu Ntaboba, L., Roobroeck, D., Bauters, M., Huygens, D., & Boeckx, P. (2015). Leaky nitrogen cycle in pristine African montane rainforest soil. Global Biogeochemical Cycles, 29(10), 1754–1762. Portico. https://doi.org/10.1002/2015gb005144