Nitrogen addition increased CO ₂ uptake more than non-CO ₂ greenhouse gases emissions in a Moso bamboo forest

Abstract

Atmospheric nitrogen (N) deposition affects the greenhouse gas (GHG) balance of ecosystems through the net atmospheric CO2 exchange and the emission of non-CO2 GHGs (CH4 and N2O). We quantified the effects of N deposition on biomass increment, soil organic carbon (SOC), and N2O and CH4 fluxes and, ultimately, the net GHG budget at ecosystem level of a Moso bamboo forest in China. Nitrogen addition significantly increased woody biomass increment and SOC decomposition, increased N2O emission, and reduced soil CH4 uptake. Despite higher N2O and CH4 fluxes, the ecosystem remained a net GHG sink of 26.8 to 29.4 megagrams of CO2 equivalent hectare−1 year−1 after 4 years of N addition against 22.7 hectare−1 year−1 without N addition. The total net carbon benefits induced by atmospheric N deposition at current rates of 30 kilograms of N hectare−1 year−1 over Moso bamboo forests across China were estimated to be of 23.8 teragrams of CO2 equivalent year−1.

Global soil‐derived ammonia emissions from agricultural nitrogen fertilizer application: A refinement based on regional and crop‐specific emission factors

“…In cropland systems, rice cultivation served as the leading background source of NH 3 emissions, where high temperature and waterlogging could be the main controls that drive NH 3 emissions from rice paddies (Bouwman et al., 2002; Xu et al., 2019). Moreover, the data on NH 3 emissions from grasslands and rice paddies as included in this study were overwhelmingly measured in subtropical and tropical regions that have been documented to be most impacted by N deposition (Song et al., 2020), which also accounted for their role as hotspots of NH 3 emissions due to increased soil deposited N input. Interestingly, compared with tilled cropping soils, no‐till cropping soils had higher background NH 3 emissions, as evidenced by the decreased NH 3 emission rates that were found after soil tillage in this analysis (Figure 2a; Table S4).…”

Nitrogen addition decreases methane uptake caused by methanotroph and methanogen imbalances in a Moso bamboo forest

“…Several field studies have observed that simulated N deposition suppresses CH 4 uptake in tropical forests in southern China, which may be attributed to the increase in inorganic N, soil Al 3+ release, and the drop in pH owing to N addition 48,49 . In addition, our previous study in the same site found that N addition significantly reduces soil CH 4 uptake in Moso bamboo forests, which is attributed to abiotic factors, such as the change in soil NH 4 + concentration and pH 50 . Previous studies have demonstrated that the abundance, diversity, and community structure of methanotrophs and methanogens are mainly influenced by soil pH 51,52 , NH 4 + concentration 16 , and soil substrate 53 .…”

Effects of weeding and fertilization on soil biology and biochemical processes and tree growth in a mixed stand of Dalbergia odorifera and Santalum album

“…(Pokharel and Chang 2016), Eucalyptus spp. (Carrero et al 2018), Pinus banksiana (Pokharel et al 2017), Cunninghamia lanceola (Wang et al 2008) and Phyllostachys edulis (Li et al 2016;Song et al 2020).…”

“…It also can affect soil biological and biochemical properties processes such as soil microbial biomass, nutrient cycling and respiration rate (Lee and Shibu 2003). Numerous studies have explored the effects of fertilizer application, especially nitrogen (N), on soil biological and biochemical processes, but results have been inconsistent; fertilizer application has significantly increased soil microbial biomass (Li et al 2010;Song et al 2020), microbial community diversity (Ramirez et al 2010) and soil respiration rate (Bowden et al 2004) and also had negative or neutral effects (Samuelson et al 2009;Sun et al 2011;Wang et al 2017). The inconsistencies can be due to differences in tree species, plantation age, site conditions and fertilizer content and dosage (Peng et al 2008).…”