Nitrogen and Phosphorus Control Soil Methane Uptake in Tropical Montane Forests

Abstract

Atmospheric concentrations of methane (CH 4 ), an important greenhouse gas, have more than doubled since pre-industrial times (Denman et al., 2007) and continue to increase at present (Turner et al., 2017(Turner et al., , 2019. About 75% of global CH 4 production, which is in total about 600 Tg yr −1 , is produced by microbial methanogenic sources, primarily in wetland soils (Conrad, 1989). In contrast, the only global biogenic sink is CH 4 uptake in aerobic soils by CH 4 -oxidizing bacteria, which perform an important ecosystem service by contributing about 5% to the total global CH 4 sink strength (Reeburgh, 2003). However, there are indications that this CH 4 sink is declining (Ni & Groffman, 2018).Tropical ecosystems play an important role in the global CH 4 budget both in terms of production, with inundated wetlands contributing about 50% to global CH 4 production (Bloom et al., 2010;Z. Zhang et al., 2017), and uptake, with tropical forest soils contributing about one third to global annual CH 4 uptake by soils (Dutaur & Verchot, 2007;Zhao et al., 2019). However, studies that compare satellite observations of CH 4 concentrations with inventories of known CH 4 sources and sinks using bottom-up modeling reveal that there are unexplained large discrepancies between modeled and observed atmospheric CH 4 concentrations in the tropics (Riley et al., 2012). This illustrates that the location and strength of CH 4 sources and sinks in the tropics are poorly constrained (Bergamaschi et al., 2009;Bloom et al., 2010;Pangala et al., 2017). Improving our understanding of the factors that control the exchange of CH 4 in tropical soils is thus a critical step toward a better-constrained CH 4 budget for tropical ecosystems.

Potential soil methane oxidation in naturally regenerated oak-dominated temperate deciduous forest stands responds to soil water status regardless of their age—an intact core incubation study

“…However, mineral N can also stimulate methanotroph activity when nitrogen is a limiting factor for microbial growth (Bodelier and Laanbroek 2004). In forests, the rate of CH 4 oxidation was found to increase with the amount of available nitrogen (Goldman et al 1995) and when low amounts of nitrogen fertilisers were added (Rigler and Zechmeister-Boltenstern 1999;Veldkamp et al 2013;Martinson et al 2021).…”

Nutrient response efficiency, soil greenhouse gas fluxes, and nutrient leaching losses from a large-scale oil palm plantation under conventional and reduced management practices

“…S3.5), was attributed to the reduction of CH4 diffusion from the atmosphere to the soil with increases in WFPS and soil bulk density (e.g. Veldkamp et al 2013;Tchiofo Lontsi et al 2020;Martinson et al 2021). Differences in soil bulk density that result from management practices in oil palm plantations (Table S1) ) affect soil total porosity, WFPS and gas diffusivity (e.g.…”

“…In contrast, high soil NO3 − level (e.g. resulting from nitrification of applied N fertilizer) can inhibit CH4 production in the soil as NO3 − is preferred over bicarbonate as an electron acceptor (Martinson et al 2021;Quiñones et al 2022). Nonetheless, across forests, smallholder rubber and oil palm plantations in Indonesia, the overriding pattern is the increase in soil CH4 uptake with increase in soil mineral N, suggesting the prevailing control of N availability on methanotrophic activity in the soil (Hassler et al 2015).…”