scholarly journals Groundwater N<sub>2</sub>O emission factors of nitrate-contaminated aquifers as derived from denitrification progress and N<sub>2</sub>O accumulation

2008 ◽  
Vol 5 (5) ◽  
pp. 1215-1226 ◽  
Author(s):  
D. Weymann ◽  
R. Well ◽  
H. Flessa ◽  
C. von der Heide ◽  
M. Deurer ◽  
...  

Abstract. We investigated the dynamics of denitrification and nitrous oxide (N2O) accumulation in 4 nitrate (NO−3) contaminated denitrifying sand and gravel aquifers of northern Germany (Fuhrberg, Sulingen, Thülsfelde and Göttingen) to quantify their potential N2O emission and to evaluate existing concepts of N2O emission factors. Excess N2 – N2 produced by denitrification – was determined by using the argon (Ar) concentration in groundwater as a natural inert tracer, assuming that this noble gas functions as a stable component and does not change during denitrification. Furthermore, initial NO−3 concentrations (NO−3 that enters the groundwater) were derived from excess N2 and actual NO−3 concentrations in groundwater in order to determine potential indirect N2O emissions as a function of the N input. Median concentrations of N2O and excess N2 ranged from 3 to 89 μg N L−1 and from 3 to 10 mg N L−1, respectively. Reaction progress (RP) of denitrification was determined as the ratio between products (N2O-N + excess N2) and starting material (initial NO−3 concentration) of the process, characterizing the different stages of denitrification. N2O concentrations were lowest at RP close to 0 and RP close to 1 but relatively high at a RP between 0.2 and 0.6. For the first time, we report groundwater N2O emission factors consisting of the ratio between N2O-N and initial NO−3-N concentrations (EF1). In addition, we determined a groundwater emission factor (EF2) using a previous concept consisting of the ratio between N2O-N and actual NO−3-N concentrations. Depending on RP, EF(1) resulted in smaller values compared to EF(2), demonstrating (i) the relevance of NO−3 consumption and consequently (ii) the need to take initial NO−3-N concentrations into account. In general, both evaluated emission factors were highly variable within and among the aquifers. The site medians ranged between 0.00043–0.00438 for EF(1) and 0.00092–0.01801 for EF(2), respectively. For the aquifers of Fuhrberg and Sulingen, we found EF(1) median values which are close to the 2006 IPCC default value of 0.0025. In contrast, we determined significant lower EF values for the aquifers of Thülsfelde and Göttingen. Summing the results up, our study supports the substantial downward revision of the IPCC default EF5-g from 0.015 (1997) to 0.0025 (2006).

2008 ◽  
Vol 5 (2) ◽  
pp. 1263-1292 ◽  
Author(s):  
D. Weymann ◽  
R. Well ◽  
H. Flessa ◽  
C. von der Heide ◽  
M. Deurer ◽  
...  

Abstract. We investigated the dynamics of denitrification and nitrous oxide (N2O) accumulation in 4 nitrate (NO3−) contaminated denitrifying sand and gravel aquifers of northern Germany (Fuhrberg, Sulingen, Thülsfelde and Göttingen) to quantify their potential N2O emission and to evaluate existing concepts of N2O emission factors. Excess N2-N2produced by denitrification – was determined by using the argon (Ar) concentration in groundwater as a natural inert tracer, assuming that this noble gas functions as a stable component and does not change during denitrification. Furthermore, initial NO3− concentrations (NO3− that enters the groundwater) were derived from excess N2 and actual NO3− concentrations in groundwater in order to determine potential indirect N2O emissions as a function of the N input. Median concentrations of N2O and excess N2 ranged from 3 to 89 μg N L−1 and from 3 to 10 mg N L−1 respectively. Reaction progress (RP) of denitrification was determined as the ratio between products (N2O-N + excess N2) and starting material (initial NO3− concentration) of the process, characterizing the different stages of denitrification. N2O concentrations were lowest at RP close to 0 and RP close to 1 but relatively high at a RP between 0.2 and 0.6. For the first time, we report groundwater N2O emission factors consisting of the ratio between N2O-N and initial NO3−-N concentrations (EF1). According to denitrification intensity, EF(1) was smaller than the ratio between N2O-N and actual NO3−-N concentrations EF(2). In general, these emission factors were highly variable within the aquifers. The site medians ranged between 0.00043–0.00438 for EF(1) and 0.00092–0.01801 for EF(2), respectively. For the aquifers of Fuhrberg and Sulingen, we found EF(1) median values which are close to the 2006 IPCC default value of 0.0025. In contrast, we determined significant lower EFs for the aquifers of Thülsfelde and Göttingen.


Soil Research ◽  
2003 ◽  
Vol 41 (3) ◽  
pp. 381 ◽  
Author(s):  
Cecile A. M. de Klein ◽  
Louise Barton ◽  
Robert R. Sherlock ◽  
Zheng Li ◽  
Roger P. Littlejohn

The Intergovernmental Panel on Climate Change methodology estimates that over 50% of total nitrous oxide (N2O) emissions in New Zealand derive from animal excreta-N deposited during grazing. The emission factor for excreta-N as used by this methodology has an important impact on New Zealand's total N2O inventory. The objectives of this study were to refine the N2O emission factor for urine by simultaneously measuring N2O emissions from 5 pastoral soils of different drainage class, in 3 different regions in New Zealand following a single application of urine; plus test various aspects of the soil cover method for determining emission factors. Cow urine and synthetic urine was applied to pastoral soils in autumn 2000 and N2O emissions were measured using closed flux chambers at regular intervals for 4–18 months following application. The N2O emission factors for cow urine estimated for the first 4 months after urine application varied greatly depending on rainfall and soil drainage class, and ranged from 0.3 to 2.5% of the urine-N applied, suggesting that adopting a single emission factor for New Zealand may be inappropriate. The largest emission factor was found in a poorly drained soil, and the lowest emission factor was found in a well-drained stony soil. Ongoing measurements on one of the soils resulted in an increase in emission factors as the N2O emissions had not reached background levels 4 months after urine application. To characterise urine-induced N2O emissions, we recommend measurements continue until N2O emissions from urine-amended soil return to background levels. Furthermore, we recommend using real animal urine rather than synthetic urine in studies when determining the N2O emission factor for urine.


2008 ◽  
Vol 48 (2) ◽  
pp. 147 ◽  
Author(s):  
Coby J. Hoogendoorn ◽  
Cecile A. M. de Klein ◽  
Alison J. Rutherford ◽  
Selai Letica ◽  
Brian P. Devantier

Urine deposited by grazing animals represents the largest source of N2O emissions in New Zealand. Sheep-grazed hill pastures are an important component of New Zealand pastoral land, but information on N2O emissions from these areas is limited. The purpose of this study was to investigate the effect of increasing rates of fertiliser nitrogen and of a nitrification inhibitor on N2O emissions from urine patches. The study was carried out in grazed paddock-scale trials at the Ballantrae and Invermay Research Stations, New Zealand. The fertiliser N treatments were 0, 100, 300 and 750 (500 for Invermay) kg N/ha.year. Nitrous oxide measurements were conducted in the spring of 2005 and 2006, following applications of synthetic sheep urine with or without dicyandiamide (DCD) in these four N treatments. In both years and at both sites, N2O emissions increased with N fertiliser application rate in both urine and non-urine affected areas. The addition of DCD to the synthetic urine reduced N2O emissions from the urine affected areas during the measurement period by 60–80% at Ballantrae and by 40% at Invermay. The N2O emission factors for the artificial sheep urine (expressed as N2O-N lost as % of N applied) ranged from 0.01 to 1.06%, with the higher values generally found in the high N fertiliser treatments. The N2O emission factors were generally less than or similar to those from sheep urine applied to flat land pasture.


Soil Research ◽  
2020 ◽  
Vol 58 (2) ◽  
pp. 198 ◽  
Author(s):  
Janquieli Schirmann ◽  
Diego Fernandes de Bastos ◽  
Douglas Adams Weiler ◽  
Murilo G. Veloso ◽  
Jeferson Dieckow ◽  
...  

Native grassland supports extensive livestock production in the Pampas of South America, but the impact of cattle excreta on nitrous oxide (N2O) emissions remains unknown in this biome. The objective of this study was to determine the N2O emission factor (EF-N2O, % of N applied that is emitted as N2O) for urine and dung from beef cattle grazing on native grasslands. A field trial was conducted under low and moderate forage allowances (FA4 and FA12; i.e. 4 and 12 kg dry matter/100 kg live weight respectively) during the 30th year of a long-term grassland experiment on a Typic Paleudult in South Brazil. Urine and dung were applied onto separate patches, at rates equivalent to one average urination or defecation; and N2O fluxes were monitored with closed static chambers over 338 days. In adjacent microplots receiving the same excreta treatment, water-filled pore space, nitrate, ammonium and extractable dissolved organic carbon were monitored in the top 0.1 m of soil. Averaged across the forage allowances, daily soil N2O fluxes were low in the control without excreta (1.3 g N ha–1), but increased upon application of dung (3.8 g N ha–1) and urine (66 g N ha–1). The annual N2O emission and the EF-N2O for urine were greater under FA12 than FA4, but no difference was observed for dung. The positive relationships between N2O-N emissions and ammonium intensity and nitrate intensity suggest that N2O may have been produced concurrently by nitrification, nitrifier/denitrification and denitrification. On average, the EF-N2O was almost 10 times higher for urine than for dung (0.74% vs 0.08%), both much lower than the IPCC’s Tier 1 default value of 2%. Our findings reinforce the need for disaggregating the EF-N2O for urine and dung and of revising the IPCC’s Tier 1 EF-N2O.


2011 ◽  
Vol 8 (6) ◽  
pp. 11529-11575
Author(s):  
B. Meda ◽  
C. R. Flechard ◽  
K. Germain ◽  
P. Robin ◽  
M. Hassouna ◽  
...  

Abstract. Nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2) fluxes over the grassy outdoor run of organically grown broilers were monitored using static chambers over two production batches in contrasted seasons. Measured N2O and CH4 fluxes were extremely variable in time and space for both batches, with fluxes ranging from a small uptake by soil to large emissions peaks, the latter of which always occurred in the chambers located closest to the broiler house. In general, fluxes decreased with increasing distance to the broiler house, demonstrating that the foraging of broilers and the amount of excreted nutrients (carbon, nitrogen) largely control the spatial variability of emissions. Spatial integration by kriging methods was carried out to provide representative fluxes on the outdoor run for each measurement day. Mechanistic relationships between plot-scale estimates and environmental conditions (soil temperature and water content) were calibrated in order to fill gaps between measurement days. Flux integration over the year 2010 showed that around 3 ± 1 kg N2O-N ha−1 were emitted on the outdoor run, equivalent to 0.9 % of outdoor N excretion and substantially lower than the IPCC default emission factor of 2 %. By contrast, the outdoor run was found to be a net CH4 sink of about −0.56 kg CH4-C ha−1, though this sink compensated less than 1.5 % (in CO2 equivalents) of N2O emissions. The net greenhouse gas (GHG) budget of the outdoor run is explored, based on measured GHG fluxes and short-term (1.5 yr) variations in soil organic carbon.


Author(s):  
Alzeneide da S. Lopes ◽  
Aderson S. de Andrade Júnior ◽  
Luís H. Bassoi ◽  
Josiane F. Silva ◽  
Edson A. Bastos ◽  
...  

ABSTRACT The objective of this study was to compare the emissions of nitrous oxide (N2O) resulting from the application of nitrogen (N) and potassium (K) doses in fertigated sugarcane, in comparison to emissions from conventional fertilizer application. The study was conducted in the experimental area of Embrapa Mid-North, Teresina, Piauí state, Brazil, from August 2014 to January 2015. The experimental design was in randomized blocks, analyzed in a (2 x 2) +1 factorial scheme, with four replicates. The treatments consisted of the combination of two doses of N and K2O (60-120 and 120-180 kg ha-1, respectively) and two methods of application (in soil and fertigation), and a control. The use of fertigation reduced the emissions of N2O in sugarcane compared with the crop under conventional fertilization. Increase in N dose from 60 to 120 kg ha-1 applied through fertigation did not affect N2O emissions, while 60 and 120 kg ha-1 applied in the soil led to 40.6 and 50.2% increases in N2O emissions, respectively. The application of 60 and 120 kg ha-1 of N in the soil led to higher N2O emission factor, being 1.39 and 2.08% higher than in the crop fertigated with 60 and 120 kg ha-1 of N, respectively.


2012 ◽  
Vol 9 (4) ◽  
pp. 1493-1508 ◽  
Author(s):  
B. Meda ◽  
C. R. Flechard ◽  
K. Germain ◽  
P. Robin ◽  
C. Walter ◽  
...  

Abstract. Nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2) fluxes over the grassy outdoor run of organically grown broilers were monitored using static chambers over two production batches in contrasted seasons. Measured N2O and CH4 fluxes were extremely variable in time and space for both batches, with fluxes ranging from a small uptake by soil to large emissions peaks, the latter of which always occurred in the chambers located closest to the broiler house. In general, fluxes decreased with increasing distance to the broiler house, demonstrating that the foraging of broilers and the amount of excreted nutrients (carbon, nitrogen) largely control the spatial variability of emissions. Spatial integration by kriging methods was carried out to provide representative fluxes on the outdoor run for each measurement day. Mechanistic relationships between plot-scale estimates and environmental conditions (soil temperature and water content) were calibrated in order to fill gaps between measurement days. Flux integration over the year 2010 showed that around 3 ± 1 kg N2O-N ha−1 were emitted on the outdoor run, equivalent to 0.9% of outdoor N excretion and substantially lower than the IPCC default emission factor of 2%. By contrast, the outdoor run was found to be a net CH4 sink of about −0.56 kg CH4-C ha−1, though this sink compensated less than 1.5% (in CO2 equivalents) of N2O emissions. The net greenhouse gas (GHG) budget of the outdoor run is explored, based on measured GHG fluxes and short-term (1.5 yr) variations in soil organic carbon.


2008 ◽  
Vol 48 (2) ◽  
pp. 213 ◽  
Author(s):  
O. T. Denmead ◽  
D. Chen ◽  
D. W. T. Griffith ◽  
Z. M. Loh ◽  
M. Bai ◽  
...  

Emissions of indirect greenhouse gases, notably the nitrogen gases ammonia (NH3) and the odd oxides of nitrogen (NOx), play important roles in the greenhouse story. Feedlots are intense, but poorly quantified, sources of atmospheric NH3 and although production of NOx is to be expected in feedlots, rates of NOx emission are virtually unknown. In the atmosphere, these gases are involved in several transformations, but eventually return to the earth in gaseous or liquid form and can then undergo further transformations involving the formation and emission of the direct greenhouse gas nitrous oxide (N2O). The IPCC Phase II guidelines estimate that indirect N2O emissions due to atmospheric deposition of N compounds formed from NH3 and NOx could be ~14% of the direct emissions from agricultural soils or from animal production systems. IPCC recommends that these indirect emissions be accounted for in making inventory estimates of N2O emission. This paper is a preliminary report of emissions of NH3 and NOx from two Australian feedlots determined with micrometeorological techniques. Emissions of nitrogen gases from both feedlots were dominated by emissions of NH3. The average NH3 emission rate over both feedlots in winter was 46 g N/animal.day, while that of NOx was less than 1% of that rate at 0.36 g N/animal.day. It was apparent that NH3 release was governed by the wetness of the surface. Rates of emission from the feedlot with the wetter surface were almost three times those from the other. The IPCC default emission factor for the combined emission of NH3 and NOx from livestock is 0.2 kg N/kg N excreted, but in our work, the emission factor was 0.59 kg N/kg N excreted. Potential emissions of N2O due to NH3 and NOx deposition were estimated to be of the same magnitude as the direct N2O emissions, the sum of direct and potential indirect amounting to ~3 g N2O-N/animal.day. If applied nationally, this would represent a contribution of N2O from Australian feedlots of 533Gg CO2-e or 2.2% of all Australian N2O emissions.


2018 ◽  
Vol 18(33) (2) ◽  
pp. 70-81
Author(s):  
Antoni Faber ◽  
Zuzanna Jarosz

The aim of the research was to verify the N2O direct and NH3 emission factors adopted in national inventories, and to estimate the direct and indirect N2O emissions in cultivation systems increasing carbon sequestration. Simulations were performed using the DNDC model for NUTS2 and Poland with the use of twenty-year series of meteorological data. It was found that the simulated direct emission of nitrous oxide for Poland was in line with the adopted emission factor. The simulated ammonia emission was greater than the assumed emission factor. Use in simulations of cultivation systems increasing the sequestration of organic carbon, such as conservation system and conventional system with manure fertilization, increased: surface leaching and runoff of nitrogen as well as direct and indirect N2O emission. The increase of these emissions must be compensated with an allowance increase in the amount of sequestered organic carbon in the soil if the greenhouse gas emissions balance is to be negative.


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