Biochar decreases soil N2O emissions in Moso bamboo plantations through decreasing labile N concentrations, N-cycling enzyme activities and nitrification/denitrification rates

Geoderma ◽  
2019 ◽  
Vol 348 ◽  
pp. 135-145 ◽  
Author(s):  
Yuze Song ◽  
Yongfu Li ◽  
Yanjiang Cai ◽  
Shenglei Fu ◽  
Yu Luo ◽  
...  
Keyword(s):  
Enzyme Activities ◽  
N Cycling ◽  
Moso Bamboo ◽  
N2o Emissions ◽  
Labile N

scholarly journals Nitrogen Cycling and Mass Balance in the World’s Mangrove Forests

Nitrogen ◽  
2020 ◽  
Vol 1 (2) ◽  
pp. 167-189
Author(s):  
Daniel M. Alongi
Keyword(s):  
N Cycling ◽  
N2o Emissions ◽  
Mangrove Forests ◽  
Cyanobacterial Mats ◽  
Total N ◽  
N Fluxes ◽  
Net Uptake ◽  
Tidal Waters ◽  
Ecosystem Flux ◽  
Slow Turnover

Nitrogen (N) cycling in mangroves is complex, with rapid turnover of low dissolved N concentrations, but slow turnover of particulate N. Most N is stored in soils. The largest sources of N are nearly equal amounts of mangrove and benthic microalgal primary production. Dissolved N fluxes between the forests and tidal waters show net uptake, indicating N conservation. N2-fixation is underestimated as rapid rates measured on tree stems, aboveground roots and cyanobacterial mats cannot currently be accounted for at the whole-forest scale due to their extreme patchiness and the inability to extrapolate beyond a localized area. Net immobilization of NH4+ is the largest ecosystem flux, indicating N retention. Denitrification is the largest loss of N, equating to 35% of total N input. Burial equates to about 29% of total inputs and is the second largest loss of N. Total inputs slightly exceed total outputs, currently suggesting net N balance in mangroves. Mangrove PON export equates to ≈95% of PON export from the world’s tropical rivers, but only 1.5% of the entire world’s river discharge. Mangrove N2O emissions, denitrification, and burial contribute 0.4%, 0.5–2.0% and 6%, respectively, to the global coastal ocean, which are disproportionate to their small worldwide area.

scholarly journals Analysis of N2O emissions and isotopomers to understand nitrogen cycling associated with multispecies grassland swards at a lysimeter scale

2020 ◽  
Author(s):  
Conor Bracken ◽  
Gary Lanigan ◽  
Karl Richards ◽  
Saoirse Tracy ◽  
Christoph Müller ◽  
...  
Keyword(s):  
Nitrogen Cycling ◽  
White Clover ◽  
Block Design ◽  
N Uptake ◽  
Soil Microbial Communities ◽  
N Cycling ◽  
N2o Emissions ◽  
Total N ◽  
Transformation Pathways ◽  
Grass Growth

<p>Nitrous oxide (N<sub>2</sub>O) is a potent greenhouse gas associated with nitrogen fertiliser inputs to agricultural production systems. Minimising N<sub>2</sub>O emissions is important to improving the efficiency and sustainability of grassland agriculture. Multispecies grassland swards composed of plants from different functional groups (grasses, legumes, herbs) have been considered as a management strategy to achieve this goal. Numerous soil nitrogen transformation pathways can lead to the production of N<sub>2</sub>O emissions. These transformation pathways are regulated by soil microbial communities and the environmental conditions and management practices that impact on them. Much research has been carried out on N cycling and N<sub>2</sub>O emissions from predominantly grass monoculture systems. However, there is a lot yet to understand about how agricultural grasslands with diverse plant communities influence soil N cycling and N<sub>2</sub>O emissions. A lysimeter experiment was set up as a completely randomised block design and carried out over a full year to investigate N<sub>2</sub>O production, and nitrogen cycling associated with four sward types. The swards four swards were: perennial ryegrass (PRG, Lolium perenne); PRG and low white clover (PRG + LWC, Trifolium repens); PRG and high white clover (PRG + HWC); PRG, WC and ribwort plantain (PRG + WC + PLAN, Plantago lanceolata) managed at 250, 90, 0, and 45 kg N ha<sup>-1</sup>yr<sup>-1</sup>, respectively. Fertiliser N was applied by syringe as urea in splits at suitable timings to meet grass growth demands. N<sub>2</sub>O fluxes were measured using a static chamber technique and additional samples were taken after the final flux sample to measure the associated N<sub>2</sub>O isotopomers using a novel Cavity Ring Down Spectroscopy technique. Leachate volumes were measured on a weekly basis and composite monthly samples were used to determine the total amount of N leached from each treatment over the full year. Herbage was harvested on a monthly basis to measure DM yield (kg DM ha<sup>-1</sup>), total N (%) and N yield (kg N ha<sup>-1</sup>).This work reports on the N<sub>2</sub>O emissions and N leaching associated with the four sward treatments and related these N losses to the treatments DM yields and N uptake as an estimation of the efficiency of these differing grassland management strategies. N<sub>2</sub>O isotopomer measurements were used to indicate N transformation pathways driving N loss over the growing season particularly around periods of peak N<sub>2</sub>O emissions.</p>

scholarly journals Fungi regulate response of N<sub>2</sub>O production to warming and grazing in a Tibetan grassland

2018 ◽  
Author(s):  
Lei Zhong ◽  
Shiping Wang ◽  
Xingliang Xu ◽  
Yanfen Wang ◽  
Yichao Rui ◽  
...  
Keyword(s):  
Land Use ◽  
Enzyme Activity ◽  
Soil Fungi ◽  
Land Use Changes ◽  
N Cycling ◽  
N2o Emissions ◽  
Production Potential ◽  
N2o Production ◽  
Winter Grazing ◽  
Nitrification And Denitrification

Abstract. Lack of understanding of the effects of warming and winter grazing on soil fungal contribution to nitrous oxide (N2O) production has limited our ability to predict N2O fluxes under changes in climate and land use management, because soil fungi play an important role in driving terrestrial N cycling. Here, we examined the effects of 10 years' warming and winter grazing on soil N2O emissions potential in an alpine meadow. Our results showed that soil bacteria and fungi contributed 46 % and 54 % to nitrification, and 37 % and 63 % to denitrification, respectively. Neither warming nor winter grazing affected the activity of enzymes responsible for overall nitrification and denitrification. However, warming significantly increased the enzyme activity of bacterial nitrification and denitrification to 53 % and 55 %, respectively. Warming significantly decreased enzyme activity of fungal nitrification and denitrification to 47 % and 45 %, respectively, while winter grazing had no such effect. We conclude that soil fungi could be the main source for N2O production potential in the Tibetan alpine grasslands. Warming and winter grazing may not affect the potential for soil N2O production potential, but climate warming can alter biotic pathways responsible for N2O production. These findings indicate that characterizing how fungal nitrification/denitrification contributes to N2O production, as well as how it responds to environmental and land use changes, can advance our understanding of N cycling. Therefore, our results provide some new insights about ecological controls on N2O production and lead to refine greenhouse gas flux models.

Influence of integrated weed management system on N-cycling microbial communities and N2O emissions

2013 ◽  
Vol 373 (1-2) ◽  
pp. 501-514 ◽  
Author(s):  
A. Vermue ◽  
L. Philippot ◽  
N. Munier-Jolain ◽  
C. Hénault ◽  
B. Nicolardot
Keyword(s):  
Microbial Communities ◽  
Weed Management ◽  
Management System ◽  
N Cycling ◽  
Integrated Weed Management ◽  
N2o Emissions

scholarly journals Sources of nitrous oxide emitted from European forest soils

2005 ◽  
Vol 2 (5) ◽  
pp. 1353-1380 ◽  
Author(s):  
P. Ambus ◽  
S. Zechmeister-Boltenstern ◽  
K. Butterbach-Bahl
Keyword(s):  
Nitrous Oxide ◽  
Forest Soils ◽  
Forest Ecosystems ◽  
C:N Ratio ◽  
N Cycling ◽  
Radiative Properties ◽  
N2o Emissions ◽  
Gross Nitrification ◽  
N2o Production ◽  
Average Contribution

Abstract. Forest ecosystems may provide strong sources of nitrous oxide (N2O), which is important for atmospheric chemical and radiative properties. Nonetheless, our understanding of controls on forest N2O emissions is insufficient to narrow current flux estimates, which still are associated with great uncertainties. In this study, we have investigated the quantitative and qualitative relationships between N-cycling and N2O production in European forests in order to evaluate the importance of nitrification and denitrification for N2O production. Soil samples were collected in 11 different sites characterized by variable climatic regimes and forest types. Soil N-cycling and associated production of N2O was assessed following application of 15N-labeled nitrogen. The N2O emission varied significantly among the different forest soils, and was inversely correlated to the soil C:N ratio. The N2O emissions were significantly higher from the deciduous soils (13 ng N2O-N cm-3d-1) than from the coniferous soils (4 ng N2O-N cm-3d-1). Nitrate (NO3-) was the dominant substrate for N2O with an average contribution of 62% and exceeding 50% at least once for all sites. The average contribution of ammonium (NH4+) to N2O averaged 34%. The N2O emissions were correlated with gross nitrification activities, and as for N2O, gross nitrification was also higher in deciduous soils (3.4 μ g N cm-3d-1) than in coniferous soils (1.1 μ g N cm-3d-1). The ratio between N2O production and gross nitrification averaged 0.67% (deciduous) and 0.44% (coniferous). Our study suggests that changes in forest composition in response to land use activities and global change may have implications for regional budgets of greenhouse gases. From the study it also became clear that N2O emissions were driven by the nitrification activity, although the N2O was produced per se mainly from denitrification. Increased nitrification in response to accelerated N inputs predicted for forest ecosystems in Europe may thus lead to increased greenhouse gas emissions from forest ecosystems.

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