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Nitrogen and Phosphorus Control Soil Methane Uptake in Tropical Montane Forests
Author(s) -
Martinson Guntars O.,
Müller Anke K.,
Matson Amanda L.,
Corre Marife D.,
Veldkamp Edzo
Publication year - 2021
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1029/2020jg005970
Subject(s) - nutrient , soil water , phosphorus , environmental science , tropics , nitrogen , agronomy , ecology , chemistry , soil science , biology , organic chemistry
Tropical forests contribute about one third to global annual CH 4 uptake by soils. Understanding the factors that control the soil‐atmosphere exchange of CH 4 at a large scale is a critical step to improve the CH 4 flux estimate for tropical soils, which is presently poorly constrained. Since tropical forest degradation often involves shifts in nutrient availabilities, it is critical to evaluate how this will affect soil CH 4 flux. Here, we report how nitrogen (N; 50 kg N ha −1 yr −1 ), phosphorus (P; 10 kg P ha −1 yr −1 ), and combined N + P additions affect soil CH 4 fluxes across an elevation gradient of tropical montane forests. We measured soil CH 4 fluxes in a nutrient application experiment at different elevations over a period of 5 years. Nutrient additions increased soil CH 4 uptake after 4–5 years of treatment but effects were not uniform across elevations. At 1,000 m, where total soil P was high, we detected mainly N limitation of soil CH 4 uptake. At 2,000 m, where total soil P was low, a strong P limitation of soil CH 4 uptake was observed. At 3,000 m, where total P was low in the organic layer but high in mineral soil, we found N limitation of soil CH 4 uptake. Our results show that projected increases of N and P depositions may increase soil CH 4 uptake in tropical montane forests but the direction, magnitude, and timing of the effects will depend on forests' nutrient status and plant‐microbial competition for N and P.