Microbial volatiles organics compounds (mvocs) emitted from soils amended with organic wastes

EABIOmEAGROSUPVolatile organic compounds (VOCs) have a central role in environmental pollution. They influence the chemistry and the composition of the atmosphere. In particular, biogenic volatile organic compounds (bVOCs) contribute 90% to global VOCs emissions1. Microorganisms contribute to bVOCs emissions and their emissions could be affected by different type of organic waste in soil2. The aim of this study is focused on determining the effect of organic wastes on VOC emitted by microorganisms in soils. The technique used for mVOC detection is the Proton Transfer Reaction-Time of Flight-Mass Spectrometry*(PTR-TOF-MS). PTR-TOF-MS technique provides on-line detection of VOC with two mains advantages: rapidity and the detection limit as low as 0.1 ppt by volume3. Five sample of the same soil with 4 different organic waste contributions were analyzed: (1) Municipal solid waste, (2) Green waste and sludge, (3) bio-waste, (4) farmyard manure and a control sample without organic waste. We also compared dry and humid conditions for each sample. Results show that VOC emissions are higher in humid samples than dry ones. Different VOCs such as acetone, Methyl Ethyl Ketone, acetaldehyde, toluene, ethanol and monoterpenes contribute between 60% and 80% of total emissions. Furthermore, other compounds emitted in smaller quantities are analyzed in order to identify a VOC profile belonging to each type of organic waste in soil. Finally, perspectives concerning the study of the correlation between mVOC emissions profiles with microorganism diversity and activity in soil will be discussed. Also analysis of soils genetic content and manipulation of genetic diversity of soils will be performed. 1 Roger Atkinson, ‘Atmospheric Chemistry of VOCs and NOx’, Atmospheric Environment, 34.12–14 (2000), 2063–2101 . 2 Mallard P. et al., ‘Impacts environnementaux de la gestion biologique des déchets : bilan des connaissances’ (2005). 3 Christos Soukoulis and others, ‘PTR-ToF-MS, A Novel, Rapid, High Sensitivity and Non-Invasive Tool to Monitor Volatile Compound Release During Fruit Post-Harvest Storage: The Case Study of Apple Ripening’, Food and Bioprocess Technology, 6.10 (2012), 2831–43 . *Financed by ANAeE France <http://www.anaee.com/

Characterisation of soil emissions of nitric oxide at field and laboratory scale using high resolution method

Agricultural soils may account for 10% of anthropogenic emissions of NO, a precursor of tropospheric ozone with potential impacts on air quality and global warming. However, the estimation of this biogenic source strength and its relationships to crop management is still challenging because of the spatial and temporal variability of the NO fluxes. Here, we present a combination of new laboratory- and field-scale methods to characterise NO emissions and single out the effects of environmental drivers. First, NO fluxes were continuously monitored over the growing season of a maize-cropped field located near Paris (France), using 6 automatic chambers. Mineral fertilizer nitrogen was applied from May to October 2005. An additional field experiment was carried out in October to test the effects of N fertilizer form on the NO emissions. The automatic chambers were designed to measure simultaneously the NO and N2O gases. Laboratory measurements were carried out in parallel using soil cores sampled at same site to test the response of NO fluxes to varying soil N-NH4 and water contents, and temperatures. The effects of soil core thickness were also analysed. The highest NO fluxes occurred during the first 5 weeks following fertilizer application. The cumulative loss of NO-N over the growing season was estimated at 1.5 kg N ha-1, i.e. 1.1% of the N fertilizer dose (140 kg N ha-1). All rainfall events induced NO peak fluxes, whose magnitude decreased over time in relation to the decline of soil inorganic N. In October, NO emissions were enhanced with ammonium forms of fertilizer N. Conversely, the application of nitrate-based fertilizers did not significantly increase NO emissions compared to an unfertilized control. The results of the subsequent laboratory experiments were in accordance with the field observations in magnitude and time variations. NO emissions were maximum with a water soil content of 15% (w w-1), and with a NH4-N content of 180 mg NH4-N kg soil-1. The response of NO fluxes to soil temperature was fitted with two exponential functions, involving a Q10 of 2.0 below 20 °C and a Q10 of 1.4 above. Field and laboratory experiments indicated that most of the NO fluxes originated from the top 10 cm of soil. The characterisation of this layer in terms of mean temperature, NH4 and water contents is thus paramount to explaining the variations of NO fluxes

Observed volatilization fluxes of S-metolachlor and benoxacor applied on soil with and without crop residues

Volatilization may represent a major dissipation pathway for pesticides applied to soils or crops, and these losses may be modified by soil surface conditions or in the presence of plant residues. This paper investigates the effect of surface conditions on volatilization through experimental results. The two experiments consisted of volatilization flux measurements for 3 days after an application of S-metolachlor together with benoxacor: one with two wind tunnels to compare the effect of the presence of crop residues on the soil on volatilization losses and another one at the field scale from bare soil without crop residues. Volatilization fluxes were large immediately after application (between 77 and 223 ng m−2 s−1 for S-metolachlor depending on experimental conditions), decreasing down to a few nanograms per square meter per second on the last day. Volatilization fluxes followed a diurnal cycle driven by environmental conditions. The losses found for both compounds were in accordance with their physicochemical properties. The crop residue on the soil surface modified soil surface conditions—primarily the soil water content essentially, the degradation of S-metolachlor, and the dynamics of volatilization loss

Volatile organic compounds sources and sinks in a wheat canopy. Analysis based on combined eddy-covariance fluxes, in-canopy profiles and chamber measurements with a PTR-TOF-Qi-MS

Volatile organic compounds sources and sinks in a wheat canopy. Analysis based on combined eddy-covariance fluxes, in-canopy profiles and chamber measurements with a PTR-TOF-Qi-MS. EGU 2017, European Geophysical Union General Assembly 201

Contamination des eaux de surface par les pesticides : extension et évaluation d’un outil d’évaluation de la part des apports aériens

Contamination des eaux de surface par les pesticides : extension et évaluation d’un outil d’évaluation de la part des apports aérien

Effect of senescence on biogenic volatile organic compound fluxes in wheat plants

International audienc

Comparative study of biogenic volatile organic compounds fluxes by wheat, maize and rapeseed with dynamic chambers over a short period in northern France

Biogenic volatile organic compounds (BVOC) are mainly emitted from vegetation. However there is still little information on BVOC exchanges with crops. In this study we measured fluxes of BVOC from wheat, maize and rapeseed crops near Paris at the plant level during a full-week period for each species. We used dynamic automated chambers coupled to a Proton Transfer Reaction, Quadrupole ion guide, Time of Flight mass spectrometer (PTR-Qi-Tof-MS) instrument for online measurements of BVOC. Our results confirm the hypothesis that many unexplored compounds contribute to BVOC exchanges between crops and the atmosphere, although for all plant species methanol was dominating the emissions (55–85% of the sum of the BVOC exchanges fluxes on a mass basis) followed by acetone and acetaldehyde. The 10 most exchanged compounds, excluding methanol, contributed more than 50% of the summed fluxes and the 100 most exchanged contributed to more than 90%. The summed BVOC emission and deposition presented large interspecies variations, but limited intra-species variability, with a summed net flux of 0.11 ± 0.02 μgBVOC gDW−1 h−1 for maize, 1.5 ± 0.7 μgBVOC gDW−1 h−1 for wheat, and 9.1 ± 2.4 μgBVOC gDW−1 h−1 for rapeseed. The 10 most emitted compounds were mostly emitted during the day and were correlated with both photosynthetically active radiation and temperature and anti-correlated with relative humidity. This study provides the first evaluation so far of the biosphere-atmosphere fluxes for several BVOC. In particular we provide a first evaluation of standard emission factor for isoprene and monoterpene for wheat and rapeseed at their respective growth stages. This study is however limited to a week period at a given stage for each species and at the plant level

Émissions de composés organiques volatils biogéniques par les écosystèmesgérés - Nouvelles références sur grandes cultures et forêts françaises et effets des pratiques agricoles

Rapport Expertises ADEMEVolatile organic compounds (VOCs) are essential compounds for atmospheric chemistry that contributeto the production of pollutants that are harmful to human health and the environment: ozone (O3) andsecondary organic aerosols (SOA). The fluxes of most VOCs, 90 % of which are biogenic (BVOCs), arenot fully quantified. Managed ecosystems, which represent about 50 % of the land area in Europe, arethe largest potential VOC source. Today, it is estimated that forests account for 55 % of the total,agricultural cover 27 %, and grasslands, wetlands and shrubs for 18 % (Karl, 2009). Furthermore, theseestimates do not adequately take into account the effects of agricultural practices due to a lack of reliabledata, especially regarding manure spreading, decomposition of litter and crop residues, pesticideapplication.In this project COV3ER, we have acquired new VOC fluxes references by a direct method on maize,wheat and rapeseed and on holm oak forest. Within this project we developed a direct method formeasuring VOC fluxes by Eddy Covariance (EC) and validated the ambient measurement of VOC bydirectly measuring the reactivity of these VOCs with the OH radical.Ecosystem-scale measurements have confirmed that BVOC emissions from crops are lower than inforests and that they are dominated by methanol, which accounted for between 55 % and 85 % of theBVOC fluxes in these Dimethyl sulphide (DMS) fluxes were also measured flows at the ecosystem level.OH reactivity measurements generally showed lower reactivity than in ecosystems with high terpenoidesemissions, although the measured OH reactivity showed peaks of up to 80 s-1. However, a comparisonof the calculated reactivity with the measured reactivity shows that about 50 % of the reactivity is notexplained by known compounds. This project also highlighted that there are different chemotypes of oak.We indeed observed a "myrcene" type, an « --pinene – sabinene » type, and a « limonene – ocimene »type.Finally, measurements of VOC emissions from organic waste products and litter have highlighted a largenumber of emitted compounds, including more reactive terpenoid compounds present in urban waste butnot in slurry.This project COV3ER provides new results and databases especially for rapeseed, for whichBVOC emissions had not previously been reported.Les composés organiques volatils (COV) constituent un élément essentiel de la chimie de l’atmosphèrequi participe à la production de polluants dangereux pour la santé humaine et l’environnement tels quel’ozone (O3) et les aérosols organiques secondaires (SOA). Les flux de la plupart des COV, dont 90 %sont d’origine biologique (COVB), ne sont pas quantifiés de façon exhaustive. Les écosystèmes gérés,qui représentent environ 50 % des surfaces terrestres en Europe, constituent le potentiel le plus importantd’émissions de COVB. On estime aujourd’hui à 55 % la part des forêts, 27 % celle des couverts agricoles,et 18 % les prairies, zones humides et arbustes (Karl, 2009). Ces estimations ne tiennent pas compte defaçon satisfaisante des effets des pratiques agricoles par manque de données fiables concernant lesépandages de lisiers, la décomposition des litières et les résidus de cultures ou encore l’application depesticides.De nouvelles références de flux des COVB ont été acquises pour le maïs, le blé et le colza et sur forêtde chêne vert. Le projet COV3ER a permis de mettre au point une méthode directe de mesure des fluxde COVB par « Eddy Covariance (EC) » et de valider la mesure ambiante de COVB par une mesuredirecte de la réactivité de ces COVB avec le radical OH.Ces mesures ont confirmé à l’échelle de l’écosystème que les émissions de COVB des couverts agricolessont plus faibles par comparaison aux émissions de COVB en forêt et qu’elles sont dominées par leméthanol qui représente entre 55 % et 85 % des flux agricoles de COVB. À noter que des flux de sulfurede diméthyle (DMS) à l’échelle de l’écosystème ont également été mesurés pour les cultures étudiéesmaïs, blé et colza. Les mesures de réactivité OH sur ces types de cultures montrent dans l’ensemble uneréactivité plus faible comparé aux mesures OH réalisées dans des écosystèmes fortement émetteurs demonoterpènes (par le chêne vert « Quercus ilex ») ou d’isoprène (par du buis en sous-bois) tel qu’observéen milieu forestier de chêne vert à Puéchabon. La réactivité OH mesurée présente tout de même despics allant jusqu’à 80 s-1. Néanmoins, la comparaison des réactivités calculées avec celles mesuréesmontre que 50 % environ de la réactivité n’est pas expliqué par les composés connus. Par ailleurs, leprojet COV3ER a mis en évidence des chémotypes différents pour le chêne vert avec des profilsd’émissions observés de type « myrcène », de type « -b-pinène-sabinène » et de type « limonène –ocimène ».Enfin, d’après des résultats obtenus au laboratoire, une grande diversité de composés organiques volatils(COVB) sont émis par les lisiers (produits résiduaires organiques PRO et litières), tandis que les déchetsverts urbains émettent surtout des composés terpénoides plus réactifs.Ces travaux de recherche sont novateurs pour certains couverts comme le colza dont les émissions deCOVB n’avaient pas été mesurées jusqu’alors