References of "Jerome, Elisabeth"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailYearly Follow-up of Methane Turbulent Exchange Over an Intensively Grazed Pasture in Belgium
Dumortier, Pierre ULg; Aubinet, Marc ULg; Beckers, Yves ULg et al

in Communications in Agricultural and Applied Biological Sciences (2014), 79(1), 91-96

Detailed reference viewed: 28 (8 ULg)
Full Text
See detailEtablissement du bilan de carbone d’une exploitation agricole wallonne pratiquant le système allaitant : effets du climat et de la gestion du pâturage. Rapport de synthèse. Janvier 2012 – Décembre 2013.
Jerome, Elisabeth ULg; Dumortier, Pierre ULg; Beckers, Yves ULg et al

Report (2013)

Dans l’optique d’une atténuation des émissions de Gaz à Effet de Serre (GES) des systèmes d’élevage, les écosystèmes prairiaux peuvent jouer un rôle important vu leur potentiel de séquestration de carbone ... [more ▼]

Dans l’optique d’une atténuation des émissions de Gaz à Effet de Serre (GES) des systèmes d’élevage, les écosystèmes prairiaux peuvent jouer un rôle important vu leur potentiel de séquestration de carbone (C) dans les sols. Une évaluation pertinente de la contribution des systèmes d’élevage herbivores aux émissions de GES nécessite de raisonner en termes de bilan, en considérant à la fois les sources de GES et leur compensation via la séquestration de carbone par les prairies. Le projet « Etablissement du bilan de carbone d’une exploitation agricole wallonne pratiquant le système allaitant : effets du climat et de la gestion du pâturage » a pour objectif d’établir un inventaire de la contribution nette des systèmes d’élevage en Wallonie aux flux de GES (CO2, N2O, CH4). A long terme, nous étudierons les possibilités de réduction de ces émissions nettes par des adaptations des modes de conduite des systèmes d’élevage en adéquation avec leurs objectifs économiques et sociaux. L’exploitation étudiée est une exploitation agricole du type « naisseur-éleveur ». L’élevage se compose de vaches allaitantes et des veaux non sevrés de l’année de race « Blanc Bleu Belge culard ». Le système d’alimentation se base essentiellement sur la prairie permanente durant la période estivale et les produits conservés de la prairie durant la période hivernale. Ce rapport constitue l’état d’avancement du projet au terme de la deuxième biennale. [less ▲]

Detailed reference viewed: 39 (11 ULg)
Full Text
See detailCattle methane fluxes measurement over an intensively grazed grassland using eddy covariance
Dumortier, Pierre ULg; Aubinet, Marc ULg; Beckers, Yves ULg et al

Poster (2013, September)

Methane emissions account for 8% of the EU-15 GHG emissions and livestock generates approximately half of these emissions (European Commission, 2009). Recent technological advances in spectroscopy now ... [more ▼]

Methane emissions account for 8% of the EU-15 GHG emissions and livestock generates approximately half of these emissions (European Commission, 2009). Recent technological advances in spectroscopy now permit methane flux measurement using eddy covariance. This method has numerous strengths. It can measure fluxes in situ, continuously and across broad areas. This provides information about meadow and cattle emission behaviour throughout the year and across a broad range of climatic conditions. We will present here a one year monitoring of methane exchange between an intensively grazed meadow and the atmosphere obtained using the eddy-covariance method. Methane fluxes exchanged by a grazed meadow were measured continuously since June 2012 at the Dorinne Terrestrial Observatory (50˚ 18’ 44” N; 4˚ 58’ 07” E; 248 m asl.) in Belgium. The site is an intensively pastured meadow of 4.2 ha managed according to the regional common practices where up to 30 Belgian Blue cows are grazing simultaneously. Flux measurements were made with the eddy covariance technique, using a fast CH4 analyzer (Picarro G2311-f) and a sonic anemometer (Campbell Csat3). Carbon dioxide fluxes and various micro-meteorological and soil variables, biomass growth and stocking rate evolution were also measured at the site. Turbulent fluxes were calculated according to standard eddy covariance computation schemes and were filtered for non-stationarity and for low friction velocity (u*) events. During grazing periods, fluxes are dominated by the enteric fermentation source and average 111 nmol m-2 s-1. They are highly variable, probably due to cow movements in and out the measurement footprint and cow digestion rhythm. Despite this spread, a daily emission rhythm is observed with higher emissions during the afternoon. When fluxes are integrated over large periods, methane emissions were found strongly related to cattle stocking rate with a slope of 7.34±0.78 mol CH4 day-1 LSU-1. Further developments are ongoing in order to improve cattle geo-localization through infra-red cameras and individual home-made GPS devices. The two systems will be compared in terms of cost, efficiency and ease of use. During cow-free periods, the methane flux averages 10.5 nmol m-2 s-1 and is highly variable with some production peaks above 100 nmol m-2 s-1. No relation was found between methane fluxes and soil temperature while a weak negative relation was found between methane fluxes and soil humidity. No soil methane absorption has been observed. European Commission. Fifth National Communication from the European Community Under the UN Framework Convention on Climate Change (UNFCCC). Technical Report - 2009 – 038 (2009). [less ▲]

Detailed reference viewed: 63 (13 ULg)
Full Text
See detailImpact of grazing on carbon dioxide flux exchanges in an intensively managed grassland
Jerome, Elisabeth ULg; Beckers, Yves ULg; Bodson, Bernard ULg et al

Poster (2013, September)

To date, there are few studies assessing the impact of specific management events, particularly grazing, on carbon (C) and carbon dioxide (CO2) fluxes in managed grasslands. Grazing effects are indeed ... [more ▼]

To date, there are few studies assessing the impact of specific management events, particularly grazing, on carbon (C) and carbon dioxide (CO2) fluxes in managed grasslands. Grazing effects are indeed difficult to discern. They vary with the stocking rate and the length of the grazing period. Moreover, they are often masked by environmental responses. The aim of the present study was to assess the impact of grazing on the CO2 fluxes of a grassland grazed by the Belgian Blue breed of cattle. The research was run at the Dorinne Terrestrial Observatory (DTO), located in the Belgian Condroz (50° 18’ 44’’ N; 4° 58’ 07’’ E; 248 m asl.). The site is a permanent grassland of ca. 4.2 ha subjected to intensive management. Grassland carbon budget at the system boundaries is calculated from Net Ecosystem Exchange of CO2 measured by eddy covariance by taking imports and exports of organic C and losses of carbon as methane into account. After 2 years of measurements, the site was close to equilibrium. If management practices (harvest, fertilization and imports as supplementary feedings) and climatic conditions had a significant impact on the C balance, the impact of grazing was uncertain, especially on CO2 fluxes. To do this analysis, we distinguished the long term and the short term impacts of grazing on CO2 fluxes. The long term effect results from the biomass consummation by the cattle and from the cattle effluents that modify assimilation and respiration fluxes. This could be quantified only by comparing fluxes before and after grazing periods. The short term impact is due to cattle respiration that is a part of total ecosystem respiration and should be measured in its presence in the field. For the long term effects of grazing on CO2 fluxes, we analyzed the temporal evolution of gross maximal photosynthetic capacity GPPmax and dark respiration normalized at 10°C (Rd,10). Those parameters were deduced from the response of daytime CO2 fluxes to radiation over 5-day windows. We calculated parameters variations between the beginning and the end of grazing and non-grazing periods (∆GPPmax, ∆Rd,10) and analyzed their dependence to stocking rate. We found a significant decreased of ∆GPPmax that allowed us to quantify the assimilation reduction due to grass consumption by cattle. Discrimination of this impact from flux response to climate was possible only after gathering and treating two years of measurements taken under various climatic conditions. At the opposite, no significant evolution of Rd,10 with the average stocking rate was found. The short term impacts were an increase of CO2 fluxes in presence of cattle. It could be distinguished and quantified only thanks to confinement experiments. Each experiment extended over two days: the first day, cattle was confined in the footprint of the eddy covariance set-up (1.76 ha, 27 LU ha-1) and the second day, it was removed from it. We compared filtered half-hourly data made at 24h intervals, in the presence or absence of cattle, considering that environmental conditions were equivalent (air temperature, wind speed, radiation and wind direction). Livestock contribution to CO2 fluxes was estimated to be 2.25 ± 0.68 kg C LU-1 d-1. [less ▲]

Detailed reference viewed: 46 (11 ULg)
Full Text
See detailTemporal variability of nitrous oxide fluxes from a fertilized grassland in Belgium: preliminary results from dynamic closed chambers.
Beekkerk van Ruth, Jöran ULg; Moureaux, Christine ULg; Degré, Aurore ULg et al

Poster (2013, April 09)

Presentation of preliminary results from N2O measurements over a grassland using dynamic closed chambers. See attached folders for more detail.

Detailed reference viewed: 15 (4 ULg)
Full Text
See detailTEMPORAL VARIABILITY OF N2O FLUXES FROM A FERTILIZED GRASSLAND: PRELIMINARY RESULTS FROM DYNAMIC CLOSED CHAMBERS
Beekkerk van Ruth, Jöran ULg; Moureaux, Christine ULg; Degré, Aurore ULg et al

Poster (2013, April 09)

This work presents preliminary results of nitrous oxide (N2O) fluxes measured by dynamic closed chambers from a fertilized grassland grazed by the Belgian Blue breed of cattle. It is part of a project ... [more ▼]

This work presents preliminary results of nitrous oxide (N2O) fluxes measured by dynamic closed chambers from a fertilized grassland grazed by the Belgian Blue breed of cattle. It is part of a project funded by the public service of Wallonia (SPW-DGARNE), whose objectives are to make a carbon/CO2 balance of the grassland (Jérôme et al., 2013) and to quantify CH4 (Dumortier et al., 2013) and N2O fluxes. The site is located in Dorinne (Dorinne Terrestrial Observatory), Belgium (50° 18’ 44” N; 4° 58’ 07” E; 248 m al.). It is a permanent grassland of ca. 4.2 ha with a moderate slope of 1 to 2 %. Mineral fertilisation took place in March and May 2012. Two cylindrical chambers of 19,2 cm diameter and 11,5 cm height were placed inside a protected area around a micrometeorological station. An infrared gas analyser (Thermofischer 46i) was used in order to measure the N2O concentrations inside of the chambers, closed by automatically controlled lids and ventilated by a constant air flow of 1liter/min. These devices were completed by adjacent soil humidity and temperature sensors. The first measurement campaign took place during June and July 2012. The chambers were installed in the field and N2O fluxes were followed without manipulation. N2O fluxes were characterised by a background emission (between 2 and 10 ngN.m2s􀀀1) on which intense but time limited peaks (between 50 and 300 ngN.m2s􀀀1) superimposed. Peaks were found to be mainly linked to fertilisation and driven by precipitation. Background fluxes were found to correlate positively with soil temperature. Secondly, a manipulation experiment took place in November 2012: two different fertilizer treatments were applied to the chambers. Doses of respectively 100 and 200 kg N/ha of ammonium nitrate were sprayed in the chambers (equivalent to a 8mmprecipitation). N2O fluxes peaked shortly after fertiliser application (respectively 300 and 550 ngN.m2s􀀀1), as well as after a posterior rain event (respectively 800 and 1500 ngN.m2s􀀀1). The peak dynamics suggests a complex interaction between soil humidity and nitrogen availability, which is under study. Dumortier et al., Geophysical Research Abstracts, Vol. 15, EGU2013-2083-1, 2013 Jérôme et al., Geophysical Research Abstracts Vol. 15, EGU2013-6989, 2013 [less ▲]

Detailed reference viewed: 79 (9 ULg)
Full Text
See detailImpact of grazing on carbon balance of an intensively grazed grassland in Belgium
Jerome, Elisabeth ULg; Beckers, Yves ULg; Beekkerk van Ruth, Jöran ULg et al

Poster (2013, April 09)

This work analyzes the impact of grazing on the carbon balance of a grassland grazed by the Belgian Blue breed of cattle. The research was run at the Dorinne terrestrial observatory (DTO). The ... [more ▼]

This work analyzes the impact of grazing on the carbon balance of a grassland grazed by the Belgian Blue breed of cattle. The research was run at the Dorinne terrestrial observatory (DTO). The experimental site is a permanent grassland of ca. 4.2 ha located in the Belgian Condroz (50° 18’ 44’’ N; 4° 58’ 07’’ E; 248 m asl.). Other studies are conducted at the DTO including measurements of methane (CH4) and nitrous oxide fluxes (Dumortier et al., Geophysical Research Abstracts, Vol. 15, EGU2013-2083-1, 2013; Beekkerk van Ruth et al., Geophysical Research Abstracts, Vol. 15, EGU2013-3211, 2013, respectively). Grassland carbon budget (Net Biome Productivity, NBP) was calculated from Net Ecosystem Exchange (NEE) measured by eddy covariance by taking imports and exports of organic C and losses of carbon as CH4 into account (Soussana et al., 2010). After 2 years of measurements (May 2010 - May 2012), the grassland behaved on average as a CO2 source (NEE = 73 ±31 g C m-2 y-1). After inclusion of all the C inputs and outputs the site was closed to equilibrium (NBP = 23 ±34 g C m-2 y-1). To analyze the impact of grazing on CO2 fluxes, we studied the temporal evolution of gross maximal photosynthetic capacity GPPmax and dark respiration Rd (deduced from the response of daytime fluxes to radiation over 5-day windows). We calculated GPPmax and Rd variation between the end and the beginning of grazing or non-grazing periods (∆GPPmax and ∆Rd, respectively). We observed a significant decrease of GPPmax during grazing periods and measured a ∆GPPmax dependence on the average stocking rate. This allows us to quantify the assimilation reduction due to grass consumption by cattle. On the contrary, no Rd decrease was observed during grazing periods. Moreover, we found that cumulated monthly NEE increased significantly with the average stocking rate. In addition, a confinement experiment was carried out in order to analyze livestock contribution to Total Ecosystem Respiration. Each experiment extended over two days: the first day, cattle was confined in the footprint of the eddy covariance set-up (1.76 ha, 27 LU ha-1) and the second day, it was removed from it. We compared filtered half-hourly data made at 24h intervals, in the presence or absence of cattle, considering that environmental conditions were equivalent (air temperature, wind speed, radiation and wind direction). Results showed that CO2 fluxes were significantly higher when cattle were on the plot. Livestock contribution estimation to CO2 fluxes was on average 6.6 µmol m-2 s-1. [less ▲]

Detailed reference viewed: 65 (12 ULg)
Full Text
See detailElevage et gaz à effet de serre : le bilan des émissions de l'animal à la filière
Dumortier, Pierre ULg; Rabier, Fabienne; Beckers, Yves ULg et al

Scientific conference (2013, February 20)

Detailed reference viewed: 11 (3 ULg)
Full Text
See detailInitiation of methane turbulent flux measurements over a grazed grassland in Belgium
Dumortier, Pierre ULg; Aubinet, Marc ULg; Chopin, Henri ULg et al

in Geophysical Research Abstracts (2013), 15

Detailed reference viewed: 21 (8 ULg)
Full Text
Peer Reviewed
See detailStockage de carbone et flux de gaz à effet de serre en prairie (synthèse bibliographique)
Jerome, Elisabeth ULg; Beckers, Yves ULg; Bodson, Bernard ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2013), 17(1), 103-117

Grassland carbon (C) sequestration can play an important role in mitigating total greenhouse gas (GHG) emissions of livestock production systems. An accurate inventory of livestock production system ... [more ▼]

Grassland carbon (C) sequestration can play an important role in mitigating total greenhouse gas (GHG) emissions of livestock production systems. An accurate inventory of livestock production system contribution to GHG emissions requires to think in terms of global budget, by considering both the GHG sources and the mitigation potential trough grassland soil carbon sequestration. There is a huge variability in C and GHG balances of grasslands that is mainly due to management practices and climatic conditions. The present article shows that, to reduce the uncertainties of the results, long term measurements at the field scale are necessary. Also, it shows the importance of taking the fluxes of the three main GHGs (carbon dioxide, nitrous oxide, methane) into account when calculating the GHG budget. This article also highlights the need for a better understanding of the mechanisms driving the fluxes, in relation to environmental factors and management practices, in order to propose mitigation strategies able to enhance soil carbon sequestration in soils and to reduce methane and nitrous oxide emissions. [less ▲]

Detailed reference viewed: 101 (15 ULg)
Full Text
See detailCarbon balance of an intensive grazed grassland
Jerome, Elisabeth ULg; Beckers, Yves ULg; Bodson, Bernard ULg et al

Poster (2012, April 23)

This work seeks to analyze the C balance of a Belgian grassland grazed by the “Blanc Bleu Belge” breed of cattle. The site is located at Dorinne in the Belgian Condroz (50° 18’ 44’’ N; 4° 58’ 07’’ E; 248 ... [more ▼]

This work seeks to analyze the C balance of a Belgian grassland grazed by the “Blanc Bleu Belge” breed of cattle. The site is located at Dorinne in the Belgian Condroz (50° 18’ 44’’ N; 4° 58’ 07’’ E; 248 m asl.). It is permanent grassland of ca. 4.2 ha with a moderate slope of 1 to 2 %. Homogeneity and topography criteria are met to ensure high quality turbulent flux measurements. The experimental field was equipped with an eddy covariance system. Flux correction, quality control and data gap filling were performed following standardised procedures. This device was completed by a micrometeorological station that measured temperature and humidity respectively in the air and within the soil, radiation, atmospheric pressure and precipitations. Carbon exported through mowing (CNBP,export), imported through compost application (CNBP,import) or through complementary feeds for cattle (CNBP,complement) was also measured. In addition, the vegetation development was followed in order to estimate herbage production and dry matter intake by grazing animals. Carbon lost through CH4 emissions (CNBP,CH4) was finally estimated, allowing the establishment of a full C budget. After one year of measurements (May 2010 - May 2011), the grassland was a net CO2 source (Net Ecosystem Exchange (NEE) = 172 ± 94 g C m-2 year-1). Net Biome Productivity (NBP) was calculated from NEE by taking into account imports and export of organic C and losses of carbon as CH4. Contribution of CNBP,CH4 to NBP was small as it was 12 ± 1 g C m-2 year-1. The balance between CNBP,import and CNBP,export created not such a large departure of NBP from NEE, which is not the case of CNBP,complement. The NBP was finally estimated at 102 ± 95 g C m-2 year-1. At this stage, it is premature to conclude about the sink or source behaviour of the plot because the NBP value is very close to its uncertainty. Moreover, this result was obtained under particular climate conditions, characterised by drought during summer 2010 and spring 2011. First year full carbon budget will be discussed in relation with climate conditions and management practices. A second year of measurements will be also presented. [less ▲]

Detailed reference viewed: 47 (7 ULg)
Full Text
See detailCarbon balance of a grazed grassland in Belgium
Jerome, Elisabeth ULg; Beckers, Yves ULg; Bodson, Bernard ULg et al

in Communications in Agricultural and Applied Biological Sciences (2012, February 10)

This work seeks to analyze the carbon balance of a managed permanent grassland grazed by the “Blanc Bleu Belge” breed of cattle. The study site is located at Dorinne. The experimental field was equipped ... [more ▼]

This work seeks to analyze the carbon balance of a managed permanent grassland grazed by the “Blanc Bleu Belge” breed of cattle. The study site is located at Dorinne. The experimental field was equipped with an eddy covariance system that measured CO2 fluxes and with a micrometeorological station. Carbon exported through mowing, imported through compost application or through complementary feeds for cattle was also measured. Carbon lost through CH4 emissions was finally estimated, allowing the establishment of a full C budget. In addition, the vegetation development was followed in order to estimate herbage production and dry matter intake by grazing animals. First year full carbon budget is presented and discussed, in relation with climate conditions and management practices. [less ▲]

Detailed reference viewed: 110 (18 ULg)
Full Text
See detailProduction de viande - réchauffement climatique
Beckers, Yves ULg; Jerome, Elisabeth ULg; Moureaux, Christine ULg et al

Article for general public (2011)

Detailed reference viewed: 106 (28 ULg)
Full Text
See detailCarbon exchange in a Belgian grassland with cattle
Jerome, Elisabeth ULg; Beckers, Yves ULg; Bodson, Bernard ULg et al

Poster (2011, April 08)

Detailed reference viewed: 69 (17 ULg)
Full Text
See detailLong term carbon dioxide exchange above a mixed forest in the Belgian Ardennes: evaluation of different approaches to deduce total ecosystem respiration from Eddy covariance measurements
Jerome, Elisabeth ULg; Heinesch, Bernard ULg; Aubinet, Marc ULg

Poster (2010, May 05)

The general aim of this research is to analyze inter annual variability of carbon dioxide (CO2) fluxes exchanged by a mixed forest located at the Vielsalm experimental site in Belgium. At this site, CO2 ... [more ▼]

The general aim of this research is to analyze inter annual variability of carbon dioxide (CO2) fluxes exchanged by a mixed forest located at the Vielsalm experimental site in Belgium. At this site, CO2 flux measurements started in 1996 and are still going on. Thirteen complete years of measurements are thus available. Net Ecosystem Exchange (NEE) inter annual variability may be driven by gross primary productivity (GPP) or Total Ecosystem Respiration (TER), which should thus be both quantified. Using flux partitioning methods, TER is deduced from NEE measurements. GPP is then obtained by subtracting TER from NEE. Initially, a robust estimation of TER is required. This work seeks to compare two independent approaches to assess TER in order to quantify the implications on inter-annual variability. The comparison was performed on twelve complete years. TER estimates can be deduced by extrapolating to the whole day NEE measurements taken during selected night or day periods. In both case, the extrapolation is performed by using a respiration response to temperature. The first approach, referred as the night-time approach, consisted in calculating TER using a temperature response function derived from night-time data sets (Reichstein et al., 2005). The second approach, referred as the daytime approach, consisted in assessing TER from the intercept of the NEE/Photosynthetically Photon Flux Density (PPFD) response (Wohlfahrt et al., 2005). For each approach, different modalities were compared: the use of long term (annual) or short term (15 days) data sets for the night-time approach and the use of different types of regression for the daytime approach. In addition, the impact of the temperature choice was studied for each of the approaches. For the night-time approach, main results showed that air temperature sensitivity of ecosystem respiration derived from annual data did not reflect the short-term air temperature sensitivity. Vielsalm is a summer active ecosystem (annual temperature sensitivity larger than short-term temperature sensitivity). Results suggested also that, for both approaches, regressions based on soil temperature gave more robust results than those based on air temperature. Furthermore, the comparison showed that the night-time and the daytime approaches give disagreeing pictures of TER inter annual variability which suggested that the choice of the approach is critical in order to correctly depict TER inter annual variability. Finally, at this stage, TER inter annual variability cannot be explained by variability of climatic conditions. [less ▲]

Detailed reference viewed: 54 (7 ULg)