scholarly journals Gas chromatography and photoacoustic spectroscopy for the assessment of soil greenhouse gases emissions

2013 ◽  
Vol 43 (2) ◽  
pp. 262-269 ◽  
Author(s):  
Rodrigo da Silveira Nicoloso ◽  
Cimélio Bayer ◽  
Genuir Luis Denega ◽  
Paulo Armando Victória de Oliveira ◽  
Martha Mayumi Higarashi ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Greenhouse Gases ◽  
Photoacoustic Spectroscopy ◽  
Cropping Systems ◽  
Agricultural Practices ◽  
N2o Emissions ◽  
N2o Fluxes ◽  
Carbon Dioxide Co2 ◽  
Ghg Fluxes

Assessments of soil carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) emissions are critical for determination of the agricultural practices' potential to mitigate global warming. This study evaluated the photoacoustic spectroscopy (PAS) for the assessment of soil greenhouse gases (GHG) fluxes in comparison to the standard gas chromatography (GC) method. Two long-term experiments with different tillage and cropping systems over a Paleudult were evaluated using static chambers. PAS measurements of CO2 and N2O concentrations showed good relationship and linearity (R2=0.98 and 0.94, respectively) with GC results. However, CH4 measurements were significantly affected by air sample moisture which interfered on CH4 detection by PAS. Overestimation of CO2 and N2O concentrations in air samples determined by PAS (14.6 and 18.7%, respectively) were also related to sampling moisture. CO2 and N2O fluxes showed good agreement between methods (R2=0.96 and 0.95, respectively), though PAS overestimated fluxes by 18.6 and 13.6% in relation to GC results, respectively. PAS showed good sensitivity and was able to detect CO2 and N2O fluxes as low as 332mg CO2 m-2 h-1 and 21µg N2O m-2 h-1. PAS analyzer should be detailed calibrated to reduce humidity interference on CO2, CH4 and N2O concentrations measurements avoiding overestimation or erroneous determination of soil GHG fluxes.

Sugarcane fields: sources or sinks for greenhouse gas emissions?

1998 ◽  
Vol 49 (1) ◽  
pp. 1 ◽  
Author(s):  
K. L. Weier
Keyword(s):  
Greenhouse Gases ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Sugar Industry ◽  
N2o Emissions ◽  
Gas Emissions ◽  
Sugarcane Crop ◽  
Management Procedures ◽  
Degree Of Certainty ◽  
Carbon Dioxide Co2

The quantities of greenhouse gases emitted into the atmosphere from sugarcane fields, and their contribution to the total emissions from Australian agriculture, have never been estimated with any degree of certainty. This review was conducted to collate the available information on greenhouse gas emissions from the Australian sugarcane crop. Estimates were made for the emissions of the 3 major greenhouse gases―carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O)―from known or suspected sources. Sinks for the sequestration of the gases also have been identified. CO2 was found to be emitted during burning of the crop and from trash-blanketed and bare sugarcane fields. Total emissions from these sources in the 1994 season were estimated at 7·6 Mt CO2-C/year. However, the sugarcane crop was identified as a major sink for C, with uptake by the crop in 1994 estimated at 13· 4 Mt CO2-C/year. N2O emanating from sugarcane soils via denitrification following application of fertiliser accounted for 45-78% of total gaseous N emissions. Estimates of N2O emissions from all land under sugarcane in 1994 totalled 4·4 kt N2O-N/year from denitrification with a further 6·3 kt N2O-N emitted from areas that are still burnt. This review suggests changes in management procedures that should limit the opportunities for denitrification in the soil and thus reduce N2O emissions. Methane evolution occurs during the smouldering phase, following burning of the crop, with production estimated at 6·7 kt CH4-C/year in 1994. CH4 oxidation in soil was identified as an important process for removal of atmospheric CH4, as were trash-blanketed soils. Although these figures are our best estimate of gaseous production from sugarcane fields, there still remains a degree of uncertainty due to sampling variability and because of the extrapolation to the entire sugarcane area. However, the coupling of new laser techniques with known micrometeorological methods will allow for a more precise sampling of greenhouse gas emissions over a larger area. Estimates would thus be more representative, resulting in a greater degree of confidence being placed in them by the sugar industry.

scholarly journals Lignite Improved the Quality of Composted Manure and Mitigated Emissions of Ammonia and Greenhouse Gases during Forced Aeration Composting

2020 ◽  
Vol 12 (24) ◽  
pp. 10528
Author(s):  
Robert Impraim ◽  
Anthony Weatherley ◽  
Trevor Coates ◽  
Deli Chen ◽  
Helen Suter
Keyword(s):  
Greenhouse Gases ◽  
Ghg Emissions ◽  
N2o Emissions ◽  
Emission Mitigation ◽  
Total N ◽  
Compost Stability ◽  
Nh3 Emission ◽  
Forced Aeration ◽  
Carbon Dioxide Co2

Lignite amendment of livestock manure is considered a viable ammonia (NH3) emission mitigation technique. However, its impact on the subsequent composting of the manure has not been well studied. This work compared changes in biochemical parameters (e.g., organic matter loss and nitrogen (N) transformation) and also the emissions of NH3 and greenhouse gases (GHGs) between lignite-amended and unamended cattle manure during forced aeration composting. Amending manure with lignite did not alter the time to compost stability despite delaying the onset of the thermophilic temperatures. Lignite treatments retained N in the manure by suppressing NH3 loss by 35–54%, resulting in lignite-amended manure composts having 10–19% more total N than the unamended compost. Relative to manure only, lignites reduced GHG emissions over the composting period: nitrous oxide (N2O) (58–72%), carbon dioxide (CO2) (12–23%) and methane (CH4) (52–59%). Low levels of CH4 and N2O emissions were observed and this was attributed to the continuous forced aeration system used in the composting. Lignite addition also improved the germination index of the final compost: 90–113% compared to 71% for manure only. These findings suggest that lignite amendment of manure has the potential to improve the quality of the final compost whilst mitigating the environmental release of NH3 and GHGs.

scholarly journals Combining two complementary micrometeorological methods to measure CH<sub>4</sub> and N<sub>2</sub>O fluxes over pasture

2015 ◽  
Vol 12 (18) ◽  
pp. 15245-15299 ◽  
Author(s):  
J. Laubach ◽  
M. Barthel ◽  
A. Fraser ◽  
J. E. Hunt ◽  
D. W. T. Griffith
Keyword(s):  
Large Fraction ◽  
Industrial Sector ◽  
N2o Emissions ◽  
Emission Rates ◽  
Co2 Fluxes ◽  
Nitrogen Inputs ◽  
Animal Excreta ◽  
N2o Fluxes ◽  
Ch4 And N2o ◽  
Carbon Dioxide Co2

Abstract. New Zealand's largest industrial sector is pastoral agriculture, giving rise to a large fraction of the country's emissions of methane (CH4) and nitrous oxide (N2O). We designed a system to continuously measure CH4 and N2O fluxes at the field scale on two adjacent pastures that differed with respect to management. At the core of this system was a closed-cell Fourier-transform infrared spectrometer (FTIR), measuring the mole fractions of CH4, N2O and carbon dioxide (CO2) at two heights at each site. In parallel, CO2 fluxes were measured using eddy-covariance instrumentation. We applied two different micrometeorological ratio methods to infer the CH4 and N2O fluxes from their respective mole fractions and the CO2 fluxes. The first is a variant of the flux-gradient method, where it is assumed that the turbulent diffusivities of CH4 and N2O equal that of CO2. This method was reliable when the CO2 mole-fraction difference between heights was at least 4 times greater than the FTIR's resolution of differences. For the second method, the temporal increases of mole fractions in the stable nocturnal boundary layer, which are correlated for concurrently-emitted gases, are used to infer the unknown fluxes of CH4 and N2O from the known flux of CO2. This method was sensitive to "contamination" from trace gas sources other than the pasture of interest and therefore required careful filtering. With both methods combined, estimates of mean daily CH4 and N2O fluxes were obtained for 60 % of days at one site and 77 % at the other. Both methods indicated both sites as net sources of CH4 and N2O. Mean emission rates for one year at the unfertilised, winter-grazed site were 8.2 (± 0.91) nmol CH4 m−2 s−1 and 0.40 (± 0.018) nmol N2O m−2 s−1. During the same year, mean emission rates at the irrigated, fertilised and rotationally-grazed site were 7.0 (± 0.89) nmol CH4 m−2 s−1 and 0.57 (± 0.019) nmol N2O m−2 s−1. At this site, the N2O emissions amounted to 1.19 (± 0.15) % of the nitrogen inputs from animal excreta and fertiliser application.

scholarly journals Temporal and spatial variations of CO<sub>2</sub>, CH<sub>4</sub> and N<sub>2</sub>O fluxes at three differently managed grasslands

2013 ◽  
Vol 10 (2) ◽  
pp. 2635-2673 ◽  
Author(s):  
D. Imer ◽  
L. Merbold ◽  
W. Eugster ◽  
N. Buchmann
Keyword(s):  
Hot Spots ◽  
Environmental Drivers ◽  
Small Scale ◽  
N2o Emissions ◽  
Functional Relationships ◽  
Temporal And Spatial ◽  
N2o Fluxes ◽  
Intensively Managed ◽  
Ghg Fluxes ◽  
Management Effects

Abstract. A profound understanding of temporal and spatial variabilities of CO2, CH4 and N2O fluxes between terrestrial ecosystems and the atmosphere is needed to reliably quantify these fluxes and to develop future mitigation strategies. For managed grassland ecosystems, temporal and spatial variabilities of these three greenhouse gas (GHG) fluxes are due to environmental drivers as well as to fertilizer applications, grazing and cutting events. To assess how these affect GHG fluxes at Swiss grassland sites, we studied three sites along an altitudinal gradient that corresponds to a management gradient: from 400 m a.s.l. (intensively managed) to 1000 m a.s.l. (moderately intensive managed) to 2000 m a.s.l. (extensively managed). Temporal and spatial variabilities of GHG fluxes were quantified along small-scale transects of 16 static soil chambers at each site. We then established functional relationships between drivers and the observed fluxes on diel and annual time scales. Furthermore, spatial variabilities and their effect on representative site-specific mean chamber GHG fluxes were assessed using geostatistical semivariogram approaches. All three grasslands were N2O sources, with mean annual fluxes ranging from 0.15 to 1.28 nmol m−2 s−1. Contrastingly, all sites were net CH4 sinks, with uptake rates ranging from −0.56 to −0.15 nmol m−2 s−1. Mean annual respiration losses of CO2, as measured with opaque chambers, ranged from 5.2 to 6.5 μmol m−2 s−1. While the environmental drivers and their respective explanatory power for N2O emissions differed considerably among the three grasslands (adjusted r2 ranging from 0.19 to 0.42), CH4 and CO2 fluxes were much better constrained (adjusted r2 ranging from 0.41 to 0.83), in particular by soil water content and air temperature, respectively. Throughout the year, spatial heterogeneity was particularly high for N2O and CH4 fluxes. We found permanent hot spots for N2O emissions and CH4 uptake at the extensively managed site. Including these hot spots in calculating the mean chamber flux was essential to obtain a representative mean flux for this ecosystem. At the intensively managed grassland, management effects clearly dominated over effects of environmental drivers on N2O fluxes. For CO2 and CH4, the importance of management effects did depend on the status of the vegetation.

scholarly journals Greenhouse gas fluxes in a drained peatland forest during spring frost-thaw event

2009 ◽  
Vol 6 (3) ◽  
pp. 6111-6145 ◽  
Author(s):  
M. K. Pihlatie ◽  
R. Kiese ◽  
N. Brüggemann ◽  
K. Butterbach-Bahl ◽  
A.-J. Kieloaho ◽  
...  
Keyword(s):  
Peat Soil ◽  
Flux Measurement ◽  
Good Alternative ◽  
N2o Emission ◽  
Soil Parameters ◽  
N2o Emissions ◽  
N2o Production ◽  
Spring Frost ◽  
Carbon Dioxide Co2 ◽  
Ghg Fluxes

Abstract. Fluxes of greenhouse gases (GHG) carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) were measured during a two month campaign at a drained peatland forest in Finland by the eddy covariance (EC) technique (CO2 and N2O), and automatic and manual chambers (CO2, CH4 and N2O). In addition, GHG concentrations and soil parameters (mineral nitrogen, temperature, moisture content) in the peat profile were measured. The aim of the measurement campaign was to quantify the GHG fluxes before, during and after thawing of the peat soil, a time period with potentially high GHG fluxes, and to compare different flux measurement methods. The forest was a net CO2 sink during the two months and the fluxes of CO2 dominated the GHG exchange. The peat soil was a small sink of atmospheric CH4 but a small source of N2O. Both CH4 oxidation and N2O production took place in the top-soil whereas CH4 was produced in the deeper layers of the peat. During the thawing of the peat distinct peaks in CO2 and N2O emissions were observed. The CO2 peak followed tightly the increase in soil temperature, whereas the N2O peak occurred with an approx. one week delay after soil thawing. CH4 fluxes did not respond to the thawing of the peat soil. The CO2 and N2O emission peaks were not captured by the manual chambers and hence we conclude that automatic chamber measurements or EC are necessary to quantify fluxes during peak emission periods. Sub-canopy EC measurements and chamber-based fluxes of CO2 and N2O were comparable, although the fluxes of N2O measured by EC were close to the detection limit of the EC system. We conclude that if fluxes are high enough, i.e. greater than 5–10 μg N m−2 h−1, the EC method is a good alternative to measure N2O and CO2 fluxes at ecosystem scale, thereby minimizing problems with chamber enclosures and spatial representativeness of the measurements.

scholarly journals Reviews and syntheses: Review of causes and sources of N<sub>2</sub>O emissions and NO<sub>3</sub> leaching from organic arable crop rotations

2019 ◽  
Vol 16 (14) ◽  
pp. 2795-2819 ◽  
Author(s):  
Sissel Hansen ◽  
Randi Berland Frøseth ◽  
Maria Stenberg ◽  
Jarosław Stalenga ◽  
Jørgen E. Olesen ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Cover Crops ◽  
Crop Residues ◽  
Cropping Systems ◽  
Crop Rotations ◽  
N2o Emissions ◽  
Arable Crop ◽  
Organic Fertilisers ◽  
N2o Fluxes

Abstract. The emissions of nitrous oxide (N2O) and leaching of nitrate (NO3) from agricultural cropping systems have considerable negative impacts on climate and the environment. Although these environmental burdens are less per unit area in organic than in non-organic production on average, they are roughly similar per unit of product. If organic farming is to maintain its goal of being environmentally friendly, these loadings must be addressed. We discuss the impact of possible drivers of N2O emissions and NO3 leaching within organic arable farming practice under European climatic conditions, and potential strategies to reduce these. Organic arable crop rotations are generally diverse with the frequent use of legumes, intercropping and organic fertilisers. The soil organic matter content and the share of active organic matter, soil structure, microbial and faunal activity are higher in such diverse rotations, and the yields are lower, than in non-organic arable cropping systems based on less diverse systems and inorganic fertilisers. Soil mineral nitrogen (SMN), N2O emissions and NO3 leaching are low under growing crops, but there is the potential for SMN accumulation and losses after crop termination, harvest or senescence. The risk of high N2O fluxes increases when large amounts of herbage or organic fertilisers with readily available nitrogen (N) and degradable carbon are incorporated into the soil or left on the surface. Freezing/thawing, drying/rewetting, compacted and/or wet soil and mechanical mixing of crop residues into the soil further enhance the risk of high N2O fluxes. N derived from soil organic matter (background emissions) does, however, seem to be the most important driver for N2O emission from organic arable crop rotations, and the correlation between yearly total N-input and N2O emissions is weak. Incorporation of N-rich plant residues or mechanical weeding followed by bare fallow conditions increases the risk of NO3 leaching. In contrast, strategic use of deep-rooted crops with long growing seasons or effective cover crops in the rotation reduces NO3 leaching risk. Enhanced recycling of herbage from green manures, crop residues and cover crops through biogas or composting may increase N efficiency and reduce N2O emissions and NO3 leaching. Mixtures of legumes (e.g. clover or vetch) and non-legumes (e.g. grasses or Brassica species) are as efficient cover crops for reducing NO3 leaching as monocultures of non-legume species. Continued regular use of cover crops has the potential to reduce NO3 leaching and enhance soil organic matter but may enhance N2O emissions. There is a need to optimise the use of crops and cover crops to enhance the synchrony of mineralisation with crop N uptake to enhance crop productivity, and this will concurrently reduce the long-term risks of NO3 leaching and N2O emissions.

scholarly journals Greenhouse gas emissions from the grassy outdoor run of organic broilers

2011 ◽  
Vol 8 (6) ◽  
pp. 11529-11575
Author(s):  
B. Meda ◽  
C. R. Flechard ◽  
K. Germain ◽  
P. Robin ◽  
M. Hassouna ◽  
...  
Keyword(s):  
Greenhouse Gas ◽  
Emission Factor ◽  
N2o Emissions ◽  
Spatial Integration ◽  
Short Term ◽  
Carbon Dioxide Co2 ◽  
Organically Grown ◽  
Broiler House ◽  
Ipcc Default ◽  
Ghg Fluxes

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.

scholarly journals Greenhouse gas emissions from the grassy outdoor run of organic broilers

2012 ◽  
Vol 9 (4) ◽  
pp. 1493-1508 ◽  
Author(s):  
B. Meda ◽  
C. R. Flechard ◽  
K. Germain ◽  
P. Robin ◽  
C. Walter ◽  
...  
Keyword(s):  
Greenhouse Gas ◽  
Emission Factor ◽  
N2o Emissions ◽  
Spatial Integration ◽  
Short Term ◽  
Carbon Dioxide Co2 ◽  
Organically Grown ◽  
Broiler House ◽  
Ipcc Default ◽  
Ghg Fluxes

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.

scholarly journals Nitrous oxide (N2O) emissions in Savanah agrosystems

2020 ◽  
pp. 1970-1976
Author(s):  
Elias Gomes de Oliveira Filho ◽  
João Carlos Medeiros ◽  
Jaqueline Dalla Rosa ◽  
Henrique Antunes de Souza ◽  
Diana Signor Deon ◽  
...  
Keyword(s):  
Cropping Systems ◽  
Plant Residue ◽  
N2o Emissions ◽  
Adjacent Area ◽  
Cultivation Systems ◽  
Residue Decomposition ◽  
N2o Fluxes ◽  
Chemical Attributes ◽  
Biological Nitrogen ◽  
Physical And Chemical

In Brazil, 87% of N2O released into the atmosphere comes from agriculture, emphasizing the importance of assessing emissions in agricultural systems. The aim of this study was to evaluate N2O fluxes and emissions in agroecosystems and to identify how physical and chemical attributes of soil may affect the emissions. The study was carried out in the northeastern savannah (Cerrado), in an area under current agricultural expansion, in the municipality of Bom Jesus, State of Piauí. The treatments were composed of grain cultivation systems under no-tillage: exclusive soybean with biological nitrogen fixation (FBN), exclusive corn and corn intercropped with brachiaria. An adjacent area under native Cerrado was evaluated as reference ecosystem. N2O fluxes were monitored using manual static chambers between February 18 and April 22, 2017, covering the period from planting until the beginning of the harvest. Corn cultivation systems presented the highest N2O fluxes and the highest total emissions. Nitrogen fertilization significantly contributed to soil N2O fluxes as opposed to FBN. The soybean system and the native Cerrado had the lowest N2O emissions. Substantial amounts of N2O may be emitted during plant residue decomposition, however, it was not evaluated in this study. The concentrations of NH4+ and NO3-available in the soil were different among the cropping systems, presenting a positive correlation with N2O fluxes.

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