scholarly journals Supporting data of the manuscript Hergoualc'h et al. (2021) Improved accuracy and reduced uncertainty in greenhouse gas inventories by refining the IPCC emission factor for direct N2O emissions from nitrogen inputs to managed soils

Author(s):  
Hergoualc'h K.
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.


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.


2010 ◽  
Vol 67 (1) ◽  
pp. 31-40 ◽  
Author(s):  
Martial Bernoux ◽  
Giacomo Branca ◽  
Aude Carro ◽  
Leslie Lipper ◽  
Garry Smith ◽  
...  

EX-ACT (EX-Ante Carbon-balance Tool) is a tool developed by the Food and Agriculture Organization of the United Nations (FAO). It provides ex-ante measurements of the mitigation impact of agriculture and forestry development projects, estimating net C balance from GHG emissions and Carbon (C) sequestration. EX-ACT is a land-based accounting system, measuring C stocks, stock changes per unit of land, and CH4 and N2O emissions expressed in t CO2-eq per hectare and year. The main output of the tool is an estimation of the C-balance associated with the adoption of improved land management options, as compared with a "business as usual" scenario. EX-ACT has been developed using primarily the IPCC 2006 Guidelines for National Greenhouse Gas Inventories, complemented by other existing methodologies and reviews of default coefficients. Default values for mitigation options in the agriculture sector are mostly from the 4th Assessment Report of IPCC (2007). Thus, EX-ACT allows for the carbonbalance appraisal of new investment programmes by ensuring an appropriate method available for donors and planning officers, project designers, and decision makers within agriculture and forestry sectors in developing countries. The tool can also help to identify the mitigation impacts of various investment project options, and thus provide an additional criterion for consideration in project selection.


Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1477
Author(s):  
Antonio Marín-Martínez ◽  
Alberto Sanz-Cobeña ◽  
Mª Angeles Bustamante ◽  
Enrique Agulló ◽  
Concepción Paredes

In semi-arid vineyard agroecosystems, highly vulnerable in the context of climate change, the soil organic matter (OM) content is crucial to the improvement of soil fertility and grape productivity. The impact of OM, from compost and animal manure, on soil properties (e.g., pH, oxidisable organic C, organic N, NH4+-N and NO3−-N), grape yield and direct greenhouse gas (GHG) emission in vineyards was assessed. For this purpose, two wine grape varieties were chosen and managed differently: with a rain-fed non-trellising vineyard of Monastrell, a drip-irrigated trellising vineyard of Monastrell and a drip-irrigated trellising vineyard of Cabernet Sauvignon. The studied fertiliser treatments were without organic amendments (C), sheep/goat manure (SGM) and distillery organic waste compost (DC). The SGM and DC treatments were applied at a rate of 4600 kg ha−1 (fresh weight, FW) and 5000 kg ha−1 FW, respectively. The use of organic amendments improved soil fertility and grape yield, especially in the drip-irrigated trellising vineyards. Increased CO2 emissions were coincident with higher grape yields and manure application (maximum CO2 emissions = 1518 mg C-CO2 m−2 d−1). In contrast, N2O emissions, mainly produced through nitrification, were decreased in the plots showing higher grape production (minimum N2O emissions = −0.090 mg N2O-N m−2 d−1). In all plots, the CH4 fluxes were negative during most of the experiment (−1.073−0.403 mg CH4-C m−2 d−1), indicating that these ecosystems can represent a significant sink for atmospheric CH4. According to our results, the optimal vineyard management, considering soil properties, yield and GHG mitigation together, was the use of compost in a drip-irrigated trellising vineyard with the grape variety Monastrell.


Author(s):  
Qi Wei ◽  
Junzeng Xu ◽  
Linxian Liao ◽  
Yawei Li ◽  
Haiyu Wang ◽  
...  

To reveal the effect of irrigation salinity on soil nitrous oxide (N2O) emission, pot experiments were designed with three irrigation salinity levels (NaCl and CaCl2 of 1, 2.5 and 4 g/L equivalence, Ec = 3.6, 8.1 and 12.7 ds/m), either for 0 kg N/ha (N0) or 120 kg N/ha (N120) nitrogen inputs. N2O emissions from soils irrigated at different salinity levels varied in a similar pattern which was triggered by soil moisture dynamics. Yet, the magnitudes of pulse N2O fluxes were significantly varied, with the peak flux at 5 g/L irrigation salinity level being much higher than at 2 and 8 g/L. Compared to fresh water irrigated soils, cumulative N2O fluxes were reduced by 22.7% and 39.6% (N0), 29.1% and 39.2% (N120) for soils irrigated with 2 and 8 g/L saline water, while they were increased by 87.7% (N0) and 58.3% (N120) for soils irrigated with 5 g/L saline water. These results suggested that the effect degree of salinity on consumption and production of N2O might vary among irrigation salinity ranges. As such, desalinating brackish water to a low salinity level (such as 2 g/L) before it is used for irrigation might be helpful for solving water resources crises and mitigating soil N2O emissions.


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).


2013 ◽  
Vol 69 (3) ◽  
pp. 451-463 ◽  
Author(s):  
D. W. de Haas ◽  
C. Pepperell ◽  
J. Foley

Primary operating data were collected from forty-six wastewater treatment plants (WWTPs) located across three states within Australia. The size range of plants was indicatively from 500 to 900,000 person equivalents. Direct and indirect greenhouse gas emissions were calculated using a mass balance approach and default emission factors, based on Australia's National Greenhouse Energy Reporting (NGER) scheme and IPCC guidelines. A Monte Carlo-type combined uncertainty analysis was applied to the some of the key emission factors in order to study sensitivity. The results suggest that Scope 2 (indirect emissions due to electrical power purchased from the grid) dominate the emissions profile for most of the plants (indicatively half to three quarters of the average estimated total emissions). This is only offset for the relatively small number of plants (in this study) that have significant on-site power generation from biogas, or where the water utility purchases grid electricity generated from renewable sources. For plants with anaerobic digestion, inventory data issues around theoretical biogas generation, capture and measurement were sometimes encountered that can skew reportable emissions using the NGER methodology. Typically, nitrous oxide (N2O) emissions dominated the Scope 1 (direct) emissions. However, N2O still only accounted for approximately 10 to 37% of total emissions. This conservative estimate is based on the ‘default’ NGER steady-state emission factor, which amounts to 1% of nitrogen removed through biological nitrification-denitrification processing in the plant (or indicatively 0.7 to 0.8% of plant influent total nitrogen). Current research suggests that true N2O emissions may be much lower and certainly not steady-state. The results of this study help to place in context research work that is focused on direct emissions from WWTPs (including N2O, methane and carbon dioxide of non-biogenic origin). For example, whereas non-biogenic CO2 contributions are relatively minor, it appears that opportunities to reduce indirect emissions as a result of modest savings in power consumption are at least in the same order as those from reducing N2O emissions. To avoid potentially high reportable emissions under NGER guidelines, particularly for methane, the onus is placed on WWTP managers to ensure that accurate plant monitoring operating records are kept.


2016 ◽  
Vol 20 (1) ◽  
pp. 109-123 ◽  
Author(s):  
M. M. R. Jahangir ◽  
K. G. Richards ◽  
M. G. Healy ◽  
L. Gill ◽  
C. Müller ◽  
...  

Abstract. The removal efficiency of carbon (C) and nitrogen (N) in constructed wetlands (CWs) is very inconsistent and frequently does not reveal whether the removal processes are due to physical attenuation or whether the different species have been transformed to other reactive forms. Previous research on nutrient removal in CWs did not consider the dynamics of pollution swapping (the increase of one pollutant as a result of a measure introduced to reduce a different pollutant) driven by transformational processes within and around the system. This paper aims to address this knowledge gap by reviewing the biogeochemical dynamics and fate of C and N in CWs and their potential impact on the environment, and by presenting novel ways in which these knowledge gaps may be eliminated. Nutrient removal in CWs varies with the type of CW, vegetation, climate, season, geographical region, and management practices. Horizontal flow CWs tend to have good nitrate (NO3−) removal, as they provide good conditions for denitrification, but cannot remove ammonium (NH4+) due to limited ability to nitrify NH4+. Vertical flow CWs have good NH4+ removal, but their denitrification ability is low. Surface flow CWs decrease nitrous oxide (N2O) emissions but increase methane (CH4) emissions; subsurface flow CWs increase N2O and carbon dioxide (CO2) emissions, but decrease CH4 emissions. Mixed species of vegetation perform better than monocultures in increasing C and N removal and decreasing greenhouse gas (GHG) emissions, but empirical evidence is still scarce. Lower hydraulic loadings with higher hydraulic retention times enhance nutrient removal, but more empirical evidence is required to determine an optimum design. A conceptual model highlighting the current state of knowledge is presented and experimental work that should be undertaken to address knowledge gaps across CWs, vegetation and wastewater types, hydraulic loading rates and regimes, and retention times, is suggested. We recommend that further research on process-based C and N removal and on the balancing of end products into reactive and benign forms is critical to the assessment of the environmental performance of CWs.


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