Effects of nitrogen and phosphorus additions on soil methane uptake in disturbed forests

Abstract

Atmospheric nitrogen (N) deposition is generally thought to suppress soil methane (CH4) uptake in natural forests, and phosphorus (P) input may alleviate this negative effect. However, it remains unclear how N and P inputs control soil CH4 uptake in disturbed forests. In this study, soil CH4 uptake rates were measured in two disturbed forests, including a secondary forest (with previous, but not recent, disturbance) and a plantation forest (with recent continuous disturbance), in southern China for 34 months of N and/or P additions: control, N addition (150 kg N ha−1 yr−1), P addition (150 kg P ha−1 yr−1), and NP addition (150 kg N ha−1 yr−1 plus 150 kg P ha−1 yr−1). Mean CH4 uptake rate in control plots was significantly higher in the secondary forest (24.40 ± 0.81 µg CH4‐C m−2 h−1) than in the plantation forest (17.07 ± 0.70 µg CH4‐C m−2 h−1). CH4 uptake rate had negative relationships with soil water‐filled pore space in both forests. In the secondary forest, N, P, and NP additions significantly decreased CH4 uptake by 39.7%, 27.8%, and 37.6%, respectively, but had no significant effects in the plantation forest, indicating that P input does not alleviate the suppression of CH4 uptake by N deposition. Taken together, our findings suggest that reducing anthropogenic disturbance, including harvesting of forest floor, and anthropogenic N and P inputs will increase soil CH4 uptake in disturbed forests, which is important in view of the increased trends in global warming during recent decades.

Nutrient limitations regulate soil greenhouse gas fluxes from tropical forests: evidence from an ecosystem-scale nutrient manipulation experiment in Uganda

“…4b, e) is attributed to the alleviation of P limitations affecting methanotrophic activity. Similar findings were reported by Zhang et al (2011), and Yu et al (2017), but contrasted those of Bréchet et al (2019) and Zheng et al (2016). It is worth noting that although all these studies were located in tropical forests, they differed fundamentally in their experimental designs, type and amount of fertilizers applied, and the frequency of fertilizer application, which could have influenced the reported CH4 uptake rates at the respective 395 sites.…”

“…CC BY 4.0 License. The annual soil CH4 fluxes from the control plots (Table 2) were at the upper end of CH4 fluxes measured in lowland tropical forests (Aronson et al, 2019;Veldkamp et al, 2013;Zheng et al, 2016), and at the lower end of those measured in (sub-) montane tropical forest ecosystems (Sousa Neto et al, 2011;Yan et al, 2008). The difference in soil texture 385 and soil moisture regimes between this experimental site and the other study sites might explain why CH4 uptake at the respective sites was different.…”

“…Yet, P deficiency typical of tropical soils can have direct impacts on ecosystem biomass production if the limitation is lifted (John et al, 2007). Furthermore, nearly all the studies so far conducted in (sub-) tropical forest ecosystems were concentrated in China (Jiang et al, 2016;Yan 85 et al, 2008;Zheng et al, 2016), Central America (Corre et al, 2014;Koehler et al, 2009a;Matson et al, 2014) and…”

Converting forests into rubber plantations weakened the soil CH4 sink in tropical uplands

“…Although growth of methanotrophic bacteria can be limited by mineral N, such as in rice paddy soils (Bodelier & Laanbroek, ), N‐limited CH 4 oxidation was often not supported by N amendment experiments in other soils. Stimulation of CH 4 oxidation occurred occasionally at low rates of N addition in forest and tree plantation systems (Geng et al, ; Koehler et al, ), but in general, adding nitrogenous fertilizer reduced CH 4 consumption by more than 20% in tree‐based ecosystems (Zhang et al, ; Zheng et al, ). In our study, NH 4 + –N was the dominant mineral N form in soils under rubber, and its concentration was comparable with that in forest soils.…”

Phosphorus alleviation of nitrogen‐suppressed methane sink in global grasslands

“…Every CH 4 flux rate corresponds to one site with auxiliary information including latitude, longitude and factors such as N deposition, P deposition, soil temperature (ST), soil moisture (SM), soil pH, soil organic carbon (SOC), bulk density (BD) and clay content (CL). Across the studies in our dataset, the N and P treatments fell within the ranges 0 ~ 200 kg N ha ‐1 yr ‐1 and 0 ~ 200 kg P ha ‐1 yr ‐1 (Mori et al ; Zheng et al ) respectively. The non‐growing season CH 4 flux is normally not available for most field experiments, therefore, the annual rate of CH 4 uptake (kg C‐CH 4 ha −1 year −1 ) thereafter was calculated by the ratio of the growing season to non‐growing season CH 4 uptake as reported by a few studies (Li et al ; Yue et al ).…”