Emissions d’ammoniac et de protoxyde d’azote au bâtiment et au stockage de fumiers bovins

Emissions d’ammoniac et de protoxyde d’azote au bâtiment et au stockage de fumiers bovins. Colloque Apivale - Produits résiduaires organiques : ingrédients clés de la bioéconomie circulair

Ammonia and nitrous oxide emissions from dairy cows on straw-based litter systems

International audienceIncreasing concerns regarding environmental impacts of animal production require a better understanding of the factors that influence nitrogen (N) excretion by animals and the processes that influence N volatilization into ammonia (NH3) and nitrous oxide (N2O) from manure. The objective of this study was to evaluate the influence of diet characteristics and climatic factors on manure composition, as well as the resulting NH3 and N2O emissions in the barn and during storage of a straw-based litter system. Two groups of three dairy cows were housed in mechanically ventilated rooms and fed with a grass-based diet (GD) or a total mixed diet (MD). The resulting solid manures were stored in ventilated tunnels. The experiment was conducted in autumn (AUT) and spring (SPR). NH3 and N2O emissions were recorded continuously (28 days in the barn, 85 days for storage). NH3–N emissions in the barn were higher for GD-AUT than for MD-AUT, which was consistent with the larger and unbalanced amount of crude and degradable protein in GD, and corroborated by higher milk urea N contents. More than 80% of the NH3–N volatilization occurred during the first week of manure storage, when the temperature of the manure heap peaked. N2O–N emissions were negligible in the barn. During storage, N2O–N emissions peaked immediately after the first week. Higher N2O–N emissions were related to higher rainfall, which may have increased the moisture content and decreased the temperature of the manure heap, thus generating the conditions necessary for nitrification and denitrification processes

Apport de produits organiques : enfouir pour limiter la volatilisation ammoniacale.: enfouir pour limiter la volatilisation ammoniacale

Apport de produits organiques : . enfouir pour limiter la volatilisation ammoniacal

Mesures d’atténuation des émissions de gaz à effet de serre en élevage bovin lait et viande

De nombreux travaux sont nécessaires pour préciser la contribution des systèmes d’élevage aux émissions de gaz à effet de serre, déterminer l’empreinte carbone du lait et de la viande bovine et identifier les leviers de réduction. Les travaux conduits dans le cadre du projet MAGES confirment qu’une incorporation de légumineuses et de chicorée à hauteur de 40 % dans le régime permet de réduire jusqu’à 20 % les émissions de méthane entérique. En bâtiment, le logement des animaux sur litière accumulée se traduit par des émissions plus élevées de méthane et de gaz carbonique. A l’échelle du système, les évaluations mettent en évidence que l’empreinte carbone brute du lait et de la viande oscillent respectivement entre 823 et 1 067 kg CO2/1 000 kg lait et 16,8 et 11,4 kg CO2/kg viande vive. Les différences observées ont trait au système fourrager, à la conduite du troupeau et de leur alimentation (suppléments lipidiques, fourrages, …) ou encore aux pratiques agronomiques (gestion des déjections, ...). Enfin le stockage de carbone qui compense jusqu’à 80 % des émissions, reste sensible aux modes de gestion des prairies et aux conditions climatiques. Les résultats obtenus et la variabilité observée illustre que la réduction de la contribution de l’élevage bovin au changement climatique est envisageable, même si des travaux de recherche complémentaires sont nécessaires pour préciser les mécanismes biologiques et les leviers.Many research works are needed to figure out the contribution of animal production systems to greenhouse gas emissions, evaluate carbon footprint of milk and beef cow and identify levers of reduction. The work led within the framework of MAGES project confirmed that an incorporation of legumes and chicory up to 40% in the diet leads to a reduction of up to 20% of enteric methane emissions. In the livestock buildings, housing of animals on an accumulated liter leads to higher emissions of methane and carbon dioxide. At the scale of the system, the assessment demonstrated that the gross carbon footprint of milk and meat fluctuates between respectively 823 and 1 067 kg CO2/1 000 kg of milk and 16.8 and 11.4 kg CO2/kg of meat. The differences noticed are linked to feed system, cattle management and diet (lipid additives, feed,…) or agronomic practices (dejection management,…). Finally, the storage of carbon, which compensates the emissions up to 80%, is sensitive to grassland management and to climatic conditions. The results provided and the observed variability illustrate that the reduction of the contribution of livestock farming to climate change is possible, even though complementary research work is needed in order to precise the biological mechanisms and the levers

EMissions d'Ammoniac et de gaz à effet de serre des FUMiers bovin (EMAFUM)

EMissions d'Ammoniac et de gaz à effet de serre des FUMiers bovin (EMAFUM

Development of a database to collect emission values for livestock systems

Growing demand for animal products has contributed to an increase in biogeochemical fluxes, leading particularly to gaseous ammonia, methane, and nitrous oxide emissions into the atmosphere. Developing accurate knowledge on the sources and magnitude of gas emissions from the livestock sector is essential to reducing emissions, while meeting other societal expectations, and to implementing effective regulations. To this end, a database called ELFE (ELevage et Facteurs d’Emission; i.e., Livestock and Emission Factors) was recently developed. It currently contains ?5200 gas emission measurements extracted from 345 publications of the international literature published from 1964 to 2018 from 37 countries. One of its innovative aspects is the structured and comprehensive description of both the livestock system and the measurement method associated with emission data. Ammonia emitted by livestock systems represents 40 to 80% of emission values and 45 to 81% of the values concern production systems with slurry, depending on the animal produced. This database will contribute to improved emission factors for national inventories by more thoroughly considering factors influencing emission levels and data quality. It highlights the need for shared and standardized reporting protocols for both the livestock system itself and the measurement conditions, to allow for thorough comparisons and to reduce uncertainty in unit conversions. The database is available online on the Institut national de la recherche agronomique (INRA) platform (https://data.inra.fr/dataset.xhtml?persistentId=doi:10.15454/MHJPYT) and will be updated annually with new gas emissions

Amélioration de la caractérisation des effluents d'élevage par des méthodes et des modèles innovants pour une meilleure prise en compte agronomique

Ce numéro d’Innovations Agronomiques correspond à la synthèse des différents projets Casdar «Innovation et Partenariat» et « Recherche Finalisée et Innovation » retenus en 2009.Le projet "Effluents d'élevage" avait pour finalité de contribuer à optimiser les épandages d’effluents d’élevage pour la fertilisation des cultures par une meilleure connaissance de leur composition et de leur comportement à l’épandage. Il a permis de mieux évaluer les besoins de caractérisation, de caractériser les effluents d’élevages, y compris ceux issus des nouveaux procédés de traitement, et de tester des méthodes innovantes de caractérisation telles que la Spectroscopie Proche Infra Rouge