Azote, colza et exploitations laitières

After exposing the main characteristics of intensive dairy farms, the authors present the advantages of rapeseed crop for these farming systems: high capability for nitrogen uptake in autumn which allows effluent spreading before winter and so gives a higher flexibility to the farmer, nutritive value of rapeseed cakes for dairy cows, positive contribution to the energetic and environmental balance at the level of the farm but also of the area. Then, the authors give the main results of an agronomic survey which has been done in the west of the France to identify the perceptions of stockbreeders concerning rapeseed crop. These data allow to know what are the questions and problems which must be solved before developing rapeseed crops in these farming systems

Effet de l'implantation d'une unité de méthanisation sur l'impact environnemental de la production de porc : cas d'une ferme en Bretagne

International audienceEffet de l'implantation d'une unité de méthanisation sur l'impact environnemental de la production de porc : cas d'une ferme en Bretagne. 47èmes Journées de la Recherche PorcineEffet de l'implantation d'une unité de méthanisation sur l'impact environnemental de la production de porc : cas d'une ferme en Bretagne. La méthanisation se développe en France dans un objectif d'atténuation des émissions de gaz à effet de serre (GES) et de production d'énergie renouvelable. Néanmoins, son développement doit s'accompagner d'un suivi environnemental notamment au niveau de la qualité des sols. L'objectif de ce travail était d'évaluer par analyse du cycle de vie (ACV) les conséquences environnementales de la mise en place d'un méthaniseur en codigestion sur une exploitation porcine en regardant plus particulièrement les effets sur la teneur en matière organique du sol. L'étude porte sur la comparaison de deux scénarios basés sur un cas type d'exploitation porcine de 225 truies produisant 4800 porcs par an, avec 1) un stockage et un épandage classique des effluents (scénario REF) ou 2) l'implantation d'un méthaniseur de 50 KW (scénario METH). L'unité fonctionnelle choisie est le kg de porc vif produit. Les modifications de l'assolement associées au scénario METH ont été prises en compte (production de triticale et d'orge en interculture pour alimenter le méthaniseur). Les deux scénarios ont été analysés par ACV en incluant des indicateurs de qualité du sol. L'analyse montre que l'implantation d'un méthaniseur sur l'exploitation réduit l'impact changement climatique de 2% (1,86 vs 1,90 kg éq. CO 2 ./kg de poids vif) et l'utilisation d'énergie de 8% (10,9 MJ/kg vs 11,8 MJ/kg). La séquestration de carbone dans le sol augmente dans les deux scénarios mais elle est plus importante pour le scénario REF (0,102 kg vs. 0,083 kg C/kg de porc). Elle atteint respectivement 0,191 et 0,166 kg C/kg de porc pour REF et METH, si toute la paille retourne au sol. Toutefois, la qualité de la matière organique contenue dans le digestat doit être caractérisée plus précisément pour pouvoir conclure sur l'impact potentiel de la séquestration du carbone. Effect of on-farm biogas production on impacts of pig production in Brittany, France For the past ten years, anaerobic digestion has developed in France for GHG mitigation and renewable energy production. However, change in soil organic matter (SOM) is another hotspot indicator for bioenergy produced from biomass by anaerobic digestion (AD). The aim of this work was to assess the influence of on-farm co-digestion of pig slurry to produce bioenergy on environmental impacts of pig production from a life cycle perspective. We compared two scenarios: (1) standard manure storage and spreading on a representative pig farm in Brittany (REF scenario) and (2) the same pig farm with a 50 kW AD plant. The functional unit was one kilogram of pig live weight produced, at the farm gate. The representative farm produces 4800 pigs per year with 225 productive sows. In the AD scenario, oats and triticale are grown as intercrops to feed the AD plant. Life cycle assessment of the two scenarios showed lower environmental impacts of the farm with AD. The introduction of an AD plant reduced climate change impact by 2% (REF: 1.90 kg CO 2-eq./kg; AD: 1.86 kg CO 2-eq./kg) and cumulative energy demand by 8% (REF: 11.8 MJ/kg; AD: 10.9 MJ/kg). SOM was sequestered in both scenarios, but the REF scenario sequestered more (0.102 kg C/kg vs. 0.083 kg C/kg for AD). Sequestration increased to 0.191 and 0.166 kg C/kg in REF and AD scenarios, respectively, if all straw was returned to the soil. C mineralization characteristics of digestate should be known more accurately before drawing conclusions about the potential impact of SOM change

Relevance Of Reduced Tillage Practices On Soil Biological, Chemical And Physical Quality And Ecosystem Services Under Organic Farming Context In Britany

Avoiding or limiting ploughing under organic farming management remains a big challenge for organic farmers. By developing an holistic approach, the aim of this study was to evaluate the impact, under organic farming management, of different tillage techniques on soil biological, physical and chemical quality and ecosystem services. In an experimental site located in Britany (France) four tillage techniques were compared: conventional ploughing (CP), agronomic ploughing (AP), superficial non-inversed tillage (C15) and very superficial non-inversed tillage (C8). Results, obtained during 10 years (from 2003 to 2013), showed a strong temporal variability between years, however some results appeared consistent. Positive impact of reduced tillage on hydraulic conductivity and organic matter content was limited to the 0-5 cm depth. No-inversed tillage (C15, C8) and agronomical ploughing (AP) significantly improved microbial biomass. C8 is the only technique which significantly decreased nematofauna. Earthworm biomass significantly decreased under conventional ploughing (CP) due to the decrease of anecic species while ploughing techniques (CP, LA) preserved total earthworm abundance due to endogeic species. Endogeic species had a negative impact on hydraulic conductivity whereas anecic enhanced the conductivity and Carbon and Phosphorus contents. No-inversed tillage techniques (C8, C15) leaded to a decrease of the crop yield, due to an increase of weeds which increased water and nutritive competition. This study highlighted the interests and limits of no-inversed techniques and agronomical ploughing applied in organic farming management for enhancing soil quality and crop yield

Azote, colza et exploitations laitières

After exposing the main characteristics of intensive dairy farms, the authors present the advantages of rapeseed crop for these farming systems: high capability for nitrogen uptake in autumn which allows effluent spreading before winter and so gives a higher flexibility to the farmer, nutritive value of rapeseed cakes for dairy cows, positive contribution to the energetic and environmental balance at the level of the farm but also of the area. Then, the authors give the main results of an agronomic survey which has been done in the west of the France to identify the perceptions of stockbreeders concerning rapeseed crop. These data allow to know what are the questions and problems which must be solved before developing rapeseed crops in these farming systems

Azote, colza et exploitations laitières

After exposing the main characteristics of intensive dairy farms, the authors present the advantages of rapeseed crop for these farming systems: high capability for nitrogen uptake in autumn which allows effluent spreading before winter and so gives a higher flexibility to the farmer, nutritive value of rapeseed cakes for dairy cows, positive contribution to the energetic and environmental balance at the level of the farm but also of the area. Then, the authors give the main results of an agronomic survey which has been done in the west of the France to identify the perceptions of stockbreeders concerning rapeseed crop. These data allow to know what are the questions and problems which must be solved before developing rapeseed crops in these farming systems

Impact du non labour sur le fonctionnement du sol.

-Dossier : Entre Agroécologie et nouvelles technologiesNational audienceabsen

Impact du non labour sur le fonctionnement du sol.

-Dossier : Entre Agroécologie et nouvelles technologiesNational audienceabsen