scholarly journals Global soil nitrous oxide emissions in a dynamic carbon-nitrogen model

2015 ◽  
Vol 12 (21) ◽  
pp. 6405-6427 ◽  
Author(s):  
Y. Huang ◽  
S. Gerber
Keyword(s):  
Nitrous Oxide ◽  
Elevated Co2 ◽  
N Uptake ◽  
N2o Emission ◽  
Nitrous Oxide Emissions ◽  
N Fixation ◽  
N Availability ◽  
Plant N Uptake ◽  
Biological N Fixation ◽  
N2o Fluxes

Abstract. Nitrous oxide (N2O) is an important greenhouse gas that also contributes to the depletion of stratospheric ozone. Due to its high temporal and spatial heterogeneity, a quantitative understanding of terrestrial N2O emission and its variabilities and responses to climate change are challenging. We added a soil N2O emission module to the dynamic global land model LM3V-N, and tested its sensitivity to mechanisms that affect the level of mineral nitrogen (N) in soil such as plant N uptake, biological N fixation, amount of volatilized N redeposited after fire, and nitrification-denitrification. We further tested the relationship between N2O emission and soil moisture, and assessed responses to elevated CO2 and temperature. Results extracted from the corresponding gridcell (without site-specific forcing data) were comparable with the average of cross-site observed annual mean emissions, although differences remained across individual sites if stand-level measurements were representative of gridcell emissions. Processes, such as plant N uptake and N loss through fire volatilization that regulate N availability for nitrification-denitrification have strong controls on N2O fluxes in addition to the parameterization of N2O loss through nitrification and denitrification. Modelled N2O fluxes were highly sensitive to water-filled pore space (WFPS), with a global sensitivity of approximately 0.25 TgN per year per 0.01 change in WFPS. We found that the global response of N2O emission to CO2 fertilization was largely determined by the response of tropical emissions with reduced N2O fluxes in the first few decades and increases afterwards. The initial reduction was linked to N limitation under higher CO2 level, and was alleviated through feedbacks such as biological N fixation. The extratropical response was weaker and generally positive, highlighting the need to expand field studies in tropical ecosystems. We did not find synergistic effects between warming and CO2 increase as reported in analyses with different models. Warming generally enhanced N2O efflux and the enhancement was greatly dampened when combined with elevated CO2, although CO2 alone had a small effect. The differential response in the tropics compared to extratropics with respect to magnitude and sign suggests caution when extrapolating from current field CO2 enrichment and warming studies to the globe.

Tillage effects on N2O emission from soils under corn and soybeans in Eastern Canada

2008 ◽  
Vol 88 (2) ◽  
pp. 153-161 ◽  
Author(s):  
E G Gregorich ◽  
P. Rochette ◽  
P. St-Georges ◽  
U F McKim ◽  
C. Chan
Keyword(s):  
Nitrous Oxide ◽  
Agricultural Soils ◽  
N2o Emission ◽  
N Fixation ◽  
Eastern Canada ◽  
N Losses ◽  
Biological N Fixation ◽  
No Till ◽  
Tillage System ◽  
Glycine Max L

The ways in which agricultural soils are managed influence the production and emission of nitrous oxide (N2O). A field study was undertaken in 2003, 2004, and 2005 to quantify and evaluate N2O emission from tilled and no-till soils under corn (Zea maysL.) and soybeans (Glycine max L. Merr) in Ontario. Overall, N2O emission was lowest in 2003, the driest and coolest of the 3 yr. In 2004, the significantly larger annual N2O emission from no-till soils and soils under corn was attributed to an episode of very high N2O emission following the application of fertilizer during a period of wet weather. That the N loss by N2O emission occurred only in no-till soils and was large and long-lasting (~4 wk) confirms the strong effect that management has in reducing fertilizer N losses. In 2005, tilled soils had significantly larger N2O emission than no-till soils, most of which was emitted before the end of June. Because the tilled soils were better aerated , nitrification was likely the primary process contributing to the larger emission. Relatively low N2O emission from soybeans suggests biological N fixation does not appear to contribute substantially to the annual N2O emission. Further study of methods to reduce N2O emission in agricultural systems should focus on improving N use efficiency within a particular tillage system rather than looking to differences between tillage systems. Key words: Tillage, corn, soybeans, nitrogen, nitrous oxide, biogenic gas emission, nitrification, denitrification, fertilization

scholarly journals Global soil nitrous oxide emissions in a dynamic carbon–nitrogen model

2015 ◽  
Vol 12 (3) ◽  
pp. 3101-3143 ◽  
Author(s):  
Y. Y. Huang ◽  
S. Gerber
Keyword(s):  
Nitrous Oxide ◽  
Elevated Co2 ◽  
Pore Space ◽  
Stratospheric Ozone ◽  
Co2 Enrichment ◽  
Field Studies ◽  
Global Scale ◽  
N2o Emission ◽  
Nitrous Oxide Emissions ◽  
Moisture Regime

Abstract. Nitrous oxide (N2O) is an important greenhouse gas that also contributes to the depletion of stratospheric ozone. With high temporal and spatial heterogeneity, a quantitative understanding of terrestrial N2O emission, its variabilities and reponses to climate change is challenging. We added a soil N2O emission module to the dynamic global land model LM3V-N, and tested its sensitivity to soil moisture regime and responses to elevated CO2 and temperature. The model was capable of reproducing the average of cross-site observed annual mean emissions, although differences remained across individual sites if stand-level measurements were representative of gridcell emissions. Modelled N2O fluxes were highly sensitive to water filled pore space (WFPS), with a global sensitivity of approximately 0.25 Tg N year−1 per 0.01 change in WFPS. We found that the global response of N2O emission to CO2 fertilization was largely determined by the response of tropical emissions, whereas the extratropical response was weaker and different, highlighting the need to expand field studies in tropical ecosystems. Warming generally enhanced N2O efflux, and the enhancement was greatly dampened when combined with elevated CO2, although CO2 alone had a small effect. Our analysis suggests caution when extrapolation from current field CO2 enrichment and warming studies to the global scale.

scholarly journals Processes regulating progressive nitrogen limitation under elevated carbon dioxide: a meta-analysis

2016 ◽  
Vol 13 (9) ◽  
pp. 2689-2699 ◽  
Author(s):  
Junyi Liang ◽  
Xuan Qi ◽  
Lara Souza ◽  
Yiqi Luo
Keyword(s):  
Elevated Co2 ◽  
Meta Analysis ◽  
Co2 Enrichment ◽  
C Sequestration ◽  
N2o Emission ◽  
N Fixation ◽  
N Cycle ◽  
Biological N Fixation ◽  
Fertilization Effect ◽  
Progressive Nitrogen Limitation

Abstract. The nitrogen (N) cycle has the potential to regulate climate change through its influence on carbon (C) sequestration. Although extensive research has explored whether or not progressive N limitation (PNL) occurs under CO2 enrichment, a comprehensive assessment of the processes that regulate PNL is still lacking. Here, we quantitatively synthesized the responses of all major processes and pools in the terrestrial N cycle with meta-analysis of CO2 experimental data available in the literature. The results showed that CO2 enrichment significantly increased N sequestration in the plant and litter pools but not in the soil pool, partially supporting one of the basic assumptions in the PNL hypothesis that elevated CO2 results in more N sequestered in organic pools. However, CO2 enrichment significantly increased the N influx via biological N fixation and the loss via N2O emission, but decreased the N efflux via leaching. In addition, no general diminished CO2 fertilization effect on plant growth was observed over time up to the longest experiment of 13 years. Overall, our analyses suggest that the extra N supply by the increased biological N fixation and decreased leaching may potentially alleviate PNL under elevated CO2 conditions in spite of the increases in plant N sequestration and N2O emission. Moreover, our syntheses indicate that CO2 enrichment increases soil ammonium (NH4+) to nitrate (NO3−) ratio. The changed NH4+/NO3− ratio and subsequent biological processes may result in changes in soil microenvironments, above-belowground community structures and associated interactions, which could potentially affect the terrestrial biogeochemical cycles. In addition, our data synthesis suggests that more long-term studies, especially in regions other than temperate ones, are needed for comprehensive assessments of the PNL hypothesis.

scholarly journals Nitrous oxide emissions from crop rotations including wheat, rapeseed and dry pea

2012 ◽  
Vol 9 (7) ◽  
pp. 9289-9314 ◽  
Author(s):  
M. H. Jeuffroy ◽  
E. Baranger ◽  
B. Carrouée ◽  
E. de Chezelles ◽  
M. Gosme ◽  
...  
Keyword(s):  
Oilseed Rape ◽  
Ghg Emissions ◽  
Global Scale ◽  
N2o Emission ◽  
Nitrous Oxide Emissions ◽  
N2o Emissions ◽  
N Fixation ◽  
Biological Fixation ◽  
Mineral N ◽  
N2o Fluxes

Abstract. Approximately 65% of anthropogenic emissions of N2O, a potent greenhouse gas, originate from soils at global scale, and particularly after N fertilisation of the main crops in Europe. Thanks to their capacity to fix atmospheric N2 through biological fixation, legumes allow to reduce N fertilizer use, and possibly N2O emission. Nevertheless, the decomposition of crop organic matter during the crop cycle and during the residue decomposition, and possibly the N fixation process itself, could lead to N2O emissions. The objective of this study was to quantify N2O emissions from a dry pea crop (Pisum sativum, harvested at maturity) and from the subsequent crops in comparison with N2O emissions from wheat and oilseed-rape crops, fertilized or not, in various rotations. A field experiment was conducted during 4 consecutive years, aiming at comparing the emissions during the pea crop, in comparison with those during the wheat (fertilized or not) or oilseed rape crops, and after the pea crop, in comparison with other preceding crops. N2O fluxes were measured using static chambers. In spite of low N2O fluxes, mainly linked with the site soil characteristics, fluxes during the crop were significantly lower for pea and unfertilized wheat than for fertilized wheat and oilseed rape. The effect of the preceding crop was not significant, while soil mineral N at harvest was higher after pea. These results, combined with the emission reduction allowed by the production and transport of the N fertiliser not applied on the pea crop, should be confirmed in a larger range of soil types. Nevertheless, they demonstrate the absence of N2O emission linked to the symbiotic N fixation process, and allow us to estimate the decrease of N2O emissions to 20–25% by including one pea crop in a three-year rotation. At a larger scale, this reduction of GHG emissions at field level has to be cumulated with the reduction of GHG emissions linked with the lower level of production and transport of the N fertiliser not applied on the pea crop.

scholarly journals Management matters: testing a mitigation strategy for nitrous oxide emissions using legumes on intensively managed grassland

2018 ◽  
Vol 15 (18) ◽  
pp. 5519-5543 ◽  
Author(s):  
Kathrin Fuchs ◽  
Lukas Hörtnagl ◽  
Nina Buchmann ◽  
Werner Eugster ◽  
Val Snow ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
N2o Emission ◽  
Mitigation Strategy ◽  
Nitrous Oxide Emissions ◽  
Plant Residues ◽  
N2o Emissions ◽  
Fixed Nitrogen ◽  
Biomass Yields ◽  
N2o Fluxes ◽  
Intensively Managed

Abstract. Replacing fertiliser nitrogen with biologically fixed nitrogen (BFN) through legumes has been suggested as a strategy for nitrous oxide (N2O) mitigation from intensively managed grasslands. While current literature provides evidence for an N2O emission reduction effect due to reduced fertiliser input, little is known about the effect of increased legume proportions potentially offsetting these reductions, i.e. by increased N2O emissions from plant residues and root exudates. In order to assess the overall effect of this mitigation strategy on permanent grassland, we performed an in situ experiment and quantified net N2O fluxes and biomass yields in two differently managed grass–clover mixtures. We measured N2O fluxes in an unfertilised parcel with high clover proportions vs. an organically fertilised control parcel with low clover proportions using the eddy covariance (EC) technique over 2 years. Furthermore, we related the measured N2O fluxes to management and environmental drivers. To assess the effect of the mitigation strategy, we measured biomass yields and quantified biologically fixed nitrogen using the 15N natural abundance method. The amount of BFN was similar in both parcels in 2015 (control: 55±5 kg N ha−1 yr−1; clover parcel: 72±5 kg N ha−1 yr−1) due to similar clover proportions (control: 15 % and clover parcel: 21 %), whereas in 2016 BFN was substantially higher in the clover parcel compared to the much lower control (control: 14±2 kg N ha−1 yr−1 with 4 % clover in DM; clover parcel: 130±8 kg N ha−1 yr−1 and 44 % clover). The mitigation management effectively reduced N2O emissions by 54 % and 39 % in 2015 and 2016, respectively, corresponding to 1.0 and 1.6 t ha−1 yr−1 CO2 equivalents. These reductions in N2O emissions can be attributed to the absence of fertilisation on the clover parcel. Differences in clover proportions during periods with no recent management showed no measurable effect on N2O emissions, indicating that the decomposition of plant residues and rhizodeposition did not compensate for the effect of fertiliser reduction on N2O emissions. Annual biomass yields were similar under mitigation management, resulting in a reduction of N2O emission intensities from 0.42 g N2O-N kg−1 DM (control) to 0.28 g N2O-N kg−1 DM (clover parcel) over the 2-year observation period. We conclude that N2O emissions from fertilised grasslands can be effectively reduced without losses in yield by increasing the clover proportion and reducing fertilisation.

scholarly journals Management matters: Testing a mitigation strategy for nitrous oxide emissions on intensively managed grassland

2018 ◽  
Author(s):  
Kathrin Fuchs ◽  
Lukas Hörtnagl ◽  
Nina Buchmann ◽  
Werner Eugster ◽  
Valerie Snow ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
N2o Emission ◽  
Mitigation Strategy ◽  
Nitrous Oxide Emissions ◽  
Environmental Drivers ◽  
Plant Residues ◽  
N2o Emissions ◽  
Biomass Yields ◽  
N2o Fluxes ◽  
Intensively Managed

Abstract. Replacing fertilizer nitrogen with biological nitrogen fixation (BNF) through legumes has been suggested as a strategy for nitrous oxide (N2O) mitigation from intensively managed grasslands. While current literature provides evidence for an N2O emission reduction effect due to reduced fertilizer input, little is known about the effect of increased legume proportions potentially offsetting these reductions, i.e. by increased N2O emissions from plant residues and root exudates. In order to assess the overall effect of this mitigation strategy on permanent grassland, we performed an in-situ experiment to quantify net N2O fluxes and biomass yields in two differently managed grass-clover mixtures. We measured N2O fluxes in an unfertilized parcel with high clover proportions vs. a fertilized control parcel with low clover proportions using the eddy–covariance (EC) technique over two years. Furthermore, we related the measured N2O fluxes to management and environmental drivers. To assess the effect of the mitigation strategy, we measured biomass yields and quantified biologically fixed nitrogen using the 15N natural abundance method. The mitigation management effectively reduced N2O emissions by 54 % and 39 % in 2015 and 2016, respectively. These reductions in N2O emissions can be attributed to the absence of fertilization on the clover parcel. Differences in clover proportions during periods with no recent management showed no measurable effect on N2O emissions, indicating that decomposition of plant residues and rhizodeposition did not compensate the effect of fertilizer reduction on N2O emissions. Annual biomass yields were similar under mitigation management, resulting in a reduction of N2O emission intensities from 0.42 g N2O-N kg−1 DM (control) to 0.28 g N2O-N kg−1 DM (clover parcel) over the two years observation period. We conclude that N2O emissions from fertilized grasslands can be effectively reduced without losses in yield by increasing the clover proportion and reducing fertilization.

scholarly journals A Research Road Map for Responsible Use of Agricultural Nitrogen

2021 ◽  
Vol 5 ◽  
Author(s):  
Michael Udvardi ◽  
Frederick E. Below ◽  
Michael J. Castellano ◽  
Alison J. Eagle ◽  
Ken E. Giller ◽  
...  
Keyword(s):  
Current Knowledge ◽  
N Uptake ◽  
Green Revolution ◽  
Sustainable Use ◽  
Industrial Process ◽  
Agricultural Practices ◽  
N Fixation ◽  
N Availability ◽  
Soil N ◽  
Biological N Fixation

Nitrogen (N) is an essential but generally limiting nutrient for biological systems. Development of the Haber-Bosch industrial process for ammonia synthesis helped to relieve N limitation of agricultural production, fueling the Green Revolution and reducing hunger. However, the massive use of industrial N fertilizer has doubled the N moving through the global N cycle with dramatic environmental consequences that threaten planetary health. Thus, there is an urgent need to reduce losses of reactive N from agriculture, while ensuring sufficient N inputs for food security. Here we review current knowledge related to N use efficiency (NUE) in agriculture and identify research opportunities in the areas of agronomy, plant breeding, biological N fixation (BNF), soil N cycling, and modeling to achieve responsible, sustainable use of N in agriculture. Amongst these opportunities, improved agricultural practices that synchronize crop N demand with soil N availability are low-hanging fruit. Crop breeding that targets root and shoot physiological processes will likely increase N uptake and utilization of soil N, while breeding for BNF effectiveness in legumes will enhance overall system NUE. Likewise, engineering of novel N-fixing symbioses in non-legumes could reduce the need for chemical fertilizers in agroecosystems but is a much longer-term goal. The use of simulation modeling to conceptualize the complex, interwoven processes that affect agroecosystem NUE, along with multi-objective optimization, will also accelerate NUE gains.

scholarly journals Biochar and urease inhibitor mitigate NH3 and N2O emissions and improve wheat yield in a urea fertilized alkaline soil

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Khadim Dawar ◽  
Shah Fahad ◽  
M. M. R. Jahangir ◽  
Iqbal Munir ◽  
Syed Sartaj Alam ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Grain Yield ◽  
Block Design ◽  
N Uptake ◽  
Nitrous Oxide Emissions ◽  
N2o Emissions ◽  
Urease Inhibitor ◽  
Alkaline Soil ◽  
Total N ◽  
N Assimilation

AbstractIn this study, we explored the role of biochar (BC) and/or urease inhibitor (UI) in mitigating ammonia (NH3) and nitrous oxide (N2O) discharge from urea fertilized wheat cultivated fields in Pakistan (34.01°N, 71.71°E). The experiment included five treatments [control, urea (150 kg N ha−1), BC (10 Mg ha−1), urea + BC and urea + BC + UI (1 L ton−1)], which were all repeated four times and were carried out in a randomized complete block design. Urea supplementation along with BC and BC + UI reduced soil NH3 emissions by 27% and 69%, respectively, compared to sole urea application. Nitrous oxide emissions from urea fertilized plots were also reduced by 24% and 53% applying BC and BC + UI, respectively, compared to urea alone. Application of BC with urea improved the grain yield, shoot biomass, and total N uptake of wheat by 13%, 24%, and 12%, respectively, compared to urea alone. Moreover, UI further promoted biomass and grain yield, and N assimilation in wheat by 38%, 22% and 27%, respectively, over sole urea application. In conclusion, application of BC and/or UI can mitigate NH3 and N2O emissions from urea fertilized soil, improve N use efficiency (NUE) and overall crop productivity.

Nitrous oxide emissions from red clover and winter wheat residues depend on interacting effects of distribution, soil N availability and moisture level

2021 ◽  
Author(s):  
Arezoo Taghizadeh-Toosi ◽  
Baldur Janz ◽  
Rodrigo Labouriau ◽  
Jørgen E. Olesen ◽  
Klaus Butterbach-Bahl ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Winter Wheat ◽  
Red Clover ◽  
Moisture Level ◽  
Nitrous Oxide Emissions ◽  
N Availability ◽  
Soil N ◽  
Soil N Availability

scholarly journals Nitrous Oxide Emissions in Pineapple Cultivation on a Tropical Peat Soil

2021 ◽  
Vol 13 (9) ◽  
pp. 4928
Author(s):  
Alicia Vanessa Jeffary ◽  
Osumanu Haruna Ahmed ◽  
Roland Kueh Jui Heng ◽  
Liza Nuriati Lim Kim Choo ◽  
Latifah Omar ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Soil Temperature ◽  
Peat Soil ◽  
Farming Systems ◽  
N2o Emission ◽  
Nitrous Oxide Emissions ◽  
Natural State ◽  
N2o Emissions ◽  
Wet Season ◽  
Peat Soils

Farming systems on peat soils are novel, considering the complexities of these organic soil. Since peat soils effectively capture greenhouse gases in their natural state, cultivating peat soils with annual or perennial crops such as pineapples necessitates the monitoring of nitrous oxide (N2O) emissions, especially from cultivated peat lands, due to a lack of data on N2O emissions. An on-farm experiment was carried out to determine the movement of N2O in pineapple production on peat soil. Additionally, the experiment was carried out to determine if the peat soil temperature and the N2O emissions were related. The chamber method was used to capture the N2O fluxes daily (for dry and wet seasons) after which gas chromatography was used to determine N2O followed by expressing the emission of this gas in t ha−1 yr−1. The movement of N2O horizontally (832 t N2O ha−1 yr−1) during the dry period was higher than in the wet period (599 t N2O ha−1 yr−1) because of C and N substrate in the peat soil, in addition to the fertilizer used in fertilizing the pineapple plants. The vertical movement of N2O (44 t N2O ha−1 yr−1) was higher in the dry season relative to N2O emission (38 t N2O ha−1 yr−1) during the wet season because of nitrification and denitrification of N fertilizer. The peat soil temperature did not affect the direction (horizontal and vertical) of the N2O emission, suggesting that these factors are not related. Therefore, it can be concluded that N2O movement in peat soils under pineapple cultivation on peat lands occurs horizontally and vertically, regardless of season, and there is a need to ensure minimum tilling of the cultivated peat soils to prevent them from being an N2O source instead of an N2O sink.

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