Aide à la décision et sélection variétale : une première étape vers des profils de blé régionalisés

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ECOHERBI : Evaluation technique, économique et environnementale depratiques de gestion de la flore adventice permettant de réduire la quantitéd’herbicides appliquée en grandes cultures

Ce numéro comprend les articles correspondant aux présentations du Colloque Casdar 2017.National audienceThe aim of ECOHERBI project was to design and evaluate different weed flora control and weeding practices to reduce herbicide uses in crops. Alongside with the valorisation of the results, it includes 3 main domains: construction and evaluation of efficient combined practice systems with little herbicides, acquisition of complementary experimental references and implementation of a digital interactive guide to help in the construction of new strategies. In testing systems, we observed a strong resilience of systems with occasional ploughing and a long rotation with or without intermediate covers. The experimental data and local surveys enabled to build a tool that provides relevant ways of exploration for the farmer willing to use less herbicide. It is also an educational tool for the acquisition of the major principles for integrated management of the weed flora.L’objectif du projet ECOHERBI est de concevoir et d’évaluer différentes techniques de contrôle de la flore adventice et des itinéraires techniques de désherbage permettant de réduire l’application d’herbicides en grandes cultures. Outre la valorisation des acquis, il comprend 3 axes majeurs : la construction et l’évaluation de systèmes de pratiques combinées économes en herbicides, l’acquisition de références expérimentales complémentaires et l’élaboration d’un guide interactif numérique d’aide à la construction de nouveaux itinéraires. Les essais de gestion intégrée ont mis en évidence une plus forte résilience des systèmes s’appuyant sur le labour occasionnel et une longue succession de cultures avec ou sans couverts intermédiaires. Les données expérimentales et les enquêtes territoriales nous ont permis de construire un outil d’aide à la décision (OAD) dont la vocation est de donner des voies d’exploration pertinentes à l’agriculteur qui souhaite utiliser une quantité moindre d’herbicide. C’est aussi un outil pédagogique permettant l’acquisition des grands principes de la gestion intégrée de la flore adventice

Modélisation et simulation par exploration statistique de chemins thermiques dans un empilement magnétique refroidi par des caloducs.

International audienceNous présentons des simulations de thermique réalisées à l'aide du code libre Stardis, basé sur un modèle statistique consistant à réaliser un grand nombre de trajets de diffusion thermique ayant pour origine la position sonde où la température doit être calculée. A titre d'exemple applicatif, nous considérons un empilement magnétique refroidi par des caloducs. Les résultats présentés portent sur un calcul stationnaire, mais la formulation et le code correspondant permettent le calcul instationnaire et le couplage des phénomènes de transport

Systèmes de culture innovants : une nouvelle génération de réseau expérimental et de réseau de compétences

Face aux évolutions de l’agriculture, aux enjeux complexes et incertains, la conception innovante (Meynard, 2006) doit favoriser le développement d’une capacité d’anticipation et d’exploration. Pour y contribuer dans le domaine des systèmes de culture en grandes cultures et polyculture-élevage, le programme CASDAR 7103 Systèmes de culture innovants s’est concrétisé par : − un réseau expérimental de 27 systèmes de culture innovants testés au champ dans 17 dispositifs, des ressources pour l’expérimentation avec des guides, des cadres d’analyses, des outils de caractérisation et d’évaluation. Aujourd’hui, il a été élargi à 70 systèmes de culture innovants dans le cadre du RMT SdCi ; − un réseau de compétences en conception – évaluation, avec quatre ateliers de conception qui ont produit 45 systèmes de culture économes en phytosanitaires, efficients en énergie et gaz à effet de serre ou favorisant la biodiversité. Son déploiement a été réalisé dans le cadre de formations d’agents de développement et d’agriculteurs (STEPHY, Certiphyto, Dephyécophyto, …), en élargissant à d’autres filières (viticulture, légumes, horticulture, arboriculture) et a pu déboucher sur des expérimentations ; − le développement d’un réseau de conseillers en accompagnement des agriculteurs dans la transition vers le développement durable, avec une démarche d’analyse réflexive en groupe des situations de conseil, et plus largement ensuite avec la production et l’édition du vademecum « Agroseil » (Cerf et al., 2012), de même que la formation « Conseiller demain » du GIS Relance agronomique. Le développement de tels réseaux de compétences dépendra aussi de la capacité à renouveler les dispositifs de recherche – développement – formation … pour une agriculture innovante et plus durable.To face evolutions of agriculture, complex and uncertain stakes, innovative conception (Meynard, 2006) must favor development of an anticipated and exploratory abilities. To contribute to this in arable and mixed cropping systems, the CASDAR 7103 program was materialized by: − an experimental network of 27 cropping systems tested in field in 17 plans, with experimental resources such as guides, analysis frames and tools of characterization and evaluation. It widened today to 70 innovative cropping systems in the “innovative cropping systems” Joint Network of Technology (JNT); − a conception and evaluation competence network, with four conception workshops which produce 45 cropping systems low in pesticides, efficient in energy and greenhouse gas emission or in favor of biodiversity. Its deployment wad realized thanks to formations of development employees and farmers (STEPHY, Certiphyto, Dephyécophyto, …) in expanding to others fields (vineyard, legumes, horticulture, arboriculture) and in new experimentations; − the development of an advisor network going with farmers in transition to sustainable development, with an approach of reflexive analysis of the advise situations in groups, and then by extension with the production and edition of the vademecum « Agroseil » (Cerf et al., 2012), as well as the formation « Advise tomorrow » of the GIS Relance agronomique. The development of such competence networks will depend also on the abilities to renew the research – development – formation plan … in order to reach an innovative and sustainable agriculture

Protection Intégrée des rotations avec Colza et blé tendre : Conception et évaluation multicritères d’itinéraires techniques économes en produits phytosanitaires

Le projet PICOBLE avait pour objectif, en se plaçant à l’échelle de l’itinéraire technique, de contribuer à la recherche de solutions permettant de réduire l’usage de produits phytosanitaires dans les systèmes de culture à base de colza et de blé. Il a permis de concevoir et de tester des ITK innovants pour différentes situations. Les résultats obtenus concluent à la possibilité d’une réduction des produits phytosanitaires de 30 à 40% sans affectation de la marge de l’agriculteur sur la base des hypothèses de prix prises, mais avec une réduction du volume de production de 10% pouvant affecter l’économie des filières avales. Les connaissances acquises permettent d’envisager de nouvelles pistes de réduction à plus long terme mais elles nécessitent encore un travail considérable, il faudra en particulier aborder des échelles plus larges au niveau du système de culture ou du paysage.Integrated protection of crop rotation with winter oilseed rape (WOSR) and winter wheat: Conception and multicriteria evaluation of pesticides saver cropping practices The PICOBLE project was looking for knowledge and knowhow likely to contribute to a reduction of pesticides use in wheat and WOSR-based rotations, at the scale of annual cropping practices. New cropping techniques have been imagined, discussed and tested in the field before being assessed with a multi-criteria approach. A 30-40% reduction of the total amount of pesticides is possible, without X. Pinochet et al. 244 Innovations Agronomiques 28 (2013), 243-256 affecting the farmer economic result under given price hypothesis, but with a 10% reduction of the production, that might affect the economic competiveness of the connected industries. Results and knowledge produced during the project open new perspectives for further reductions on the longer term. Nevertheless, work is still needed and approaches have to be extended to cropping systems and landscapes scales

Increasing species richness and genetic diversity in agriculture: results of the Wheatamix project

Homogenization and intensive use of inputs have provided major productivity gains in agriculture during the 20th century. However, new solutions are now needed to face the quest for greater agricultural sustainability. A better use of crop genetic diversity should be an essential leverage, as it could promote various ecosystem services, in a context of increasing environmental stochasticity caused by global change. Increasing within field diversity through the use of cultivar mixtures is a timely option, testified by with some significant “success stories” in the past, and recent bibliographic reviews. Yet, cultivar mixtures are poorly developed worldwide. In this context, the Wheatamix project studies the interest of mixing wheat genotypes to reinforce the sustainability, resilience, and multi-functionality of agriculture. Analyzing the interactions among genotypes and with the environment, Wheatamix develop new blending and breeding methods to obtain performing mixtures. Complementary experimental approaches are being deployed: i) a diversity experiment (88 large wheat plots with 1, 2, 4 or 8 varieties) to quantify the effects of wheat diversity on ecosystem services; ii) replicates of the same diversity experiment in 4 sites across France under low and high inputs, to test diversity effects under a wide range of soil and climate conditions; iii) a network of 30 farms, encompassing agro-climatic variability in the Paris basin, to compare the ecological and techno-economic performance of blends and monocultures. The first results characterize various ecosystem services provided by genetic diversity (yield stability; regulation of foliar diseases; insect pest and weed biocontrol; maintenance of soil fertility; biodiversity conservation), and raise important methodological and statistical issues, crucial when studying the causal link between bundles of functional traits and delivered groups of services. Finally, the Wheatamix project emphasizes the need of a pluri-disciplinary approach when addressing agroecological subjects, and illustrates the strong mutual benefices between agronomic and ecological sciences

Increasing species richness and genetic diversity in agriculture: results of the Wheatamix project

Homogenization and intensive use of inputs have provided major productivity gains in agriculture during the 20th century. However, new solutions are now needed to face the quest for greater agricultural sustainability. A better use of crop genetic diversity should be an essential leverage, as it could promote various ecosystem services, in a context of increasing environmental stochasticity caused by global change. Increasing within field diversity through the use of cultivar mixtures is a timely option, testified by with some significant “success stories” in the past, and recent bibliographic reviews. Yet, cultivar mixtures are poorly developed worldwide. In this context, the Wheatamix project studies the interest of mixing wheat genotypes to reinforce the sustainability, resilience, and multi-functionality of agriculture. Analyzing the interactions among genotypes and with the environment, Wheatamix develop new blending and breeding methods to obtain performing mixtures. Complementary experimental approaches are being deployed: i) a diversity experiment (88 large wheat plots with 1, 2, 4 or 8 varieties) to quantify the effects of wheat diversity on ecosystem services; ii) replicates of the same diversity experiment in 4 sites across France under low and high inputs, to test diversity effects under a wide range of soil and climate conditions; iii) a network of 30 farms, encompassing agro-climatic variability in the Paris basin, to compare the ecological and techno-economic performance of blends and monocultures. The first results characterize various ecosystem services provided by genetic diversity (yield stability; regulation of foliar diseases; insect pest and weed biocontrol; maintenance of soil fertility; biodiversity conservation), and raise important methodological and statistical issues, crucial when studying the causal link between bundles of functional traits and delivered groups of services. Finally, the Wheatamix project emphasizes the need of a pluri-disciplinary approach when addressing agroecological subjects, and illustrates the strong mutual benefices between agronomic and ecological sciences

An interdisciplinary approach to increase wheat within-field diversity and promote agro-ecosystem services

International audienceOne major challenge for increasing agriculture sustainability is to better mobilize crop genetic diversity, as prone by agroecology. A simple way to increase within-field diversity is to use cultivar mixtures, and this has been successfully applied to a few crops in the past. Despite numerous scientific papers documeting the value of cultivar mixtures in wheat and other cereals, especially to control diseases, their cultivation has remained marginal throughout the world. To understand the origin of this gap between scientific knowledge and agricultural practices, the French project Wheatamix explored the synergies mobilized by cultivar mixtures, their impact on various ecosystem services, and their potential to reinforce the sustainability, resilience, and multi-functionality of agriculture. It focused on the agro-ecological and socio-economic impacts of variety associations at different scales, from the plant level up to the wheat supply chain. The project aims at developing new blending and breeding methods to design performing mixtures.To understand how plant-to-plant interactions shape wheat mixtures performances, Wheatamix has set five objectives: 1) describe the variability of morphological and ecological traits in a panel of 57 varieties; 2) explore variability by blending 16 contrasted varieties from the panel into 72 mixtures, composed of 2, 4, and 8 components; 3) study the ecosystem services provided; 4) assess the technical and economic performances in farmer conditions; 5) evaluate the impact of cultivar mixtures on the wheat supply chain. To achieve these goals, this project has developed an interdisciplinary approach, mobilizing agronomy, ecology, economics, ecophysiology, epidemiology, genetics, and management sciences. The project brought together scientists from 10 labs, as well as agricultural advisers and farmers from 6 French counties. The project first described the functional diversity of 57 varieties, highlighting the effects of modern breeding on trait variability, that lowered variability of traits subject to direct selection, and impacted both plant architecture, physiological traits as nutrient absorption, but also trade-off between traits. Wheatamix then surveyed how variation in mixture diversity impacted wild communities. A first result highlighted the low abundance of macro-organisms in this experiment: no relationship was found between the number of varieties in a mixture and the diversity/abundance of earthworms, weeds, mycorrhizae, springtails, beetles, nematodes. However, a significant effect of mixture diversity on the abundance of some spiders, and on nitrifying bacteria, was observed. Coming to ecosystem services, disease regulation (rust and septoria) has been confirmed as the most strongly and positively affected by varietal associations, raising also the strong effects of architectural variability of the canopy (septoria). Diversity also contributed to higher predation rates on aphids. Lastly, soil nitrification and denitrification activities were significantly affected by mixture diversity on 4 surveyed sites, contributing to a shift in plant nutrition and positive effect of greenhouse gas emission.Co-design of variety mixtures was carried out with farmers, technical advisers, and scientists. For three years, 30 farmers in the Paris basin proposed varietal blends and measured their performance on their farms. This exchange first highlighted that the first goals for farmers was to i) secure their production ii) simplify plot management. Then co-design workshops allowed to propose assembly rules and design mixtures, resulting in a wide diversity of sown mixtures. Field trials revealed that in more than 70% of the cases, the mixture had a higher yield than the mean of its components. This work highlighted farmers needs and resulted in a Multicriteria Evaluation Tool, helping farmers and advisers to design mixtures. The survey of the wheat supply chain finally highlighted the need for a concerted innovation among the various actors. Finally, Wheatamix also developed new statistical method to infer mixing ability, allowing both to blend the best mixers, and also to propose new breeding methods.Coupling various disciplines and approaches, such as ecophysiological modeling of plant competition (FSPM WALTer), field and controlled experiments, theoretical framework in ecology (sampling vs complementarity effects, functional traits and tradeoff), and mixture co-design and surveys with stakeholders, Wheatamix has allowed to understand the interest of cultivar mixtures for farmers. Wheat cultivar mixtures are experiencing an exponential growth: they only represented 2% of bread wheat sown in 2010, and are presently at 8%, raking at the first position on the cultivar list. Wheatamix emphasizes the need for an interdisciplinary approach when addressing agroecological subjects, and illustrates the strong mutual benefices between agronomic and ecological sciences

An interdisciplinary approach to increase wheat within-field diversity and promote agro-ecosystem services

International audienceOne major challenge for increasing agriculture sustainability is to better mobilize crop genetic diversity, as prone by agroecology. A simple way to increase within-field diversity is to use cultivar mixtures, and this has been successfully applied to a few crops in the past. Despite numerous scientific papers documeting the value of cultivar mixtures in wheat and other cereals, especially to control diseases, their cultivation has remained marginal throughout the world. To understand the origin of this gap between scientific knowledge and agricultural practices, the French project Wheatamix explored the synergies mobilized by cultivar mixtures, their impact on various ecosystem services, and their potential to reinforce the sustainability, resilience, and multi-functionality of agriculture. It focused on the agro-ecological and socio-economic impacts of variety associations at different scales, from the plant level up to the wheat supply chain. The project aims at developing new blending and breeding methods to design performing mixtures.To understand how plant-to-plant interactions shape wheat mixtures performances, Wheatamix has set five objectives: 1) describe the variability of morphological and ecological traits in a panel of 57 varieties; 2) explore variability by blending 16 contrasted varieties from the panel into 72 mixtures, composed of 2, 4, and 8 components; 3) study the ecosystem services provided; 4) assess the technical and economic performances in farmer conditions; 5) evaluate the impact of cultivar mixtures on the wheat supply chain. To achieve these goals, this project has developed an interdisciplinary approach, mobilizing agronomy, ecology, economics, ecophysiology, epidemiology, genetics, and management sciences. The project brought together scientists from 10 labs, as well as agricultural advisers and farmers from 6 French counties. The project first described the functional diversity of 57 varieties, highlighting the effects of modern breeding on trait variability, that lowered variability of traits subject to direct selection, and impacted both plant architecture, physiological traits as nutrient absorption, but also trade-off between traits. Wheatamix then surveyed how variation in mixture diversity impacted wild communities. A first result highlighted the low abundance of macro-organisms in this experiment: no relationship was found between the number of varieties in a mixture and the diversity/abundance of earthworms, weeds, mycorrhizae, springtails, beetles, nematodes. However, a significant effect of mixture diversity on the abundance of some spiders, and on nitrifying bacteria, was observed. Coming to ecosystem services, disease regulation (rust and septoria) has been confirmed as the most strongly and positively affected by varietal associations, raising also the strong effects of architectural variability of the canopy (septoria). Diversity also contributed to higher predation rates on aphids. Lastly, soil nitrification and denitrification activities were significantly affected by mixture diversity on 4 surveyed sites, contributing to a shift in plant nutrition and positive effect of greenhouse gas emission.Co-design of variety mixtures was carried out with farmers, technical advisers, and scientists. For three years, 30 farmers in the Paris basin proposed varietal blends and measured their performance on their farms. This exchange first highlighted that the first goals for farmers was to i) secure their production ii) simplify plot management. Then co-design workshops allowed to propose assembly rules and design mixtures, resulting in a wide diversity of sown mixtures. Field trials revealed that in more than 70% of the cases, the mixture had a higher yield than the mean of its components. This work highlighted farmers needs and resulted in a Multicriteria Evaluation Tool, helping farmers and advisers to design mixtures. The survey of the wheat supply chain finally highlighted the need for a concerted innovation among the various actors. Finally, Wheatamix also developed new statistical method to infer mixing ability, allowing both to blend the best mixers, and also to propose new breeding methods.Coupling various disciplines and approaches, such as ecophysiological modeling of plant competition (FSPM WALTer), field and controlled experiments, theoretical framework in ecology (sampling vs complementarity effects, functional traits and tradeoff), and mixture co-design and surveys with stakeholders, Wheatamix has allowed to understand the interest of cultivar mixtures for farmers. Wheat cultivar mixtures are experiencing an exponential growth: they only represented 2% of bread wheat sown in 2010, and are presently at 8%, raking at the first position on the cultivar list. Wheatamix emphasizes the need for an interdisciplinary approach when addressing agroecological subjects, and illustrates the strong mutual benefices between agronomic and ecological sciences

An interdisciplinary approach to increase wheat within-field diversity and promote agro-ecosystem services

International audienceOne major challenge for increasing agriculture sustainability is to better mobilize crop genetic diversity, as prone by agroecology. A simple way to increase within-field diversity is to use cultivar mixtures, and this has been successfully applied to a few crops in the past. Despite numerous scientific papers documeting the value of cultivar mixtures in wheat and other cereals, especially to control diseases, their cultivation has remained marginal throughout the world. To understand the origin of this gap between scientific knowledge and agricultural practices, the French project Wheatamix explored the synergies mobilized by cultivar mixtures, their impact on various ecosystem services, and their potential to reinforce the sustainability, resilience, and multi-functionality of agriculture. It focused on the agro-ecological and socio-economic impacts of variety associations at different scales, from the plant level up to the wheat supply chain. The project aims at developing new blending and breeding methods to design performing mixtures.To understand how plant-to-plant interactions shape wheat mixtures performances, Wheatamix has set five objectives: 1) describe the variability of morphological and ecological traits in a panel of 57 varieties; 2) explore variability by blending 16 contrasted varieties from the panel into 72 mixtures, composed of 2, 4, and 8 components; 3) study the ecosystem services provided; 4) assess the technical and economic performances in farmer conditions; 5) evaluate the impact of cultivar mixtures on the wheat supply chain. To achieve these goals, this project has developed an interdisciplinary approach, mobilizing agronomy, ecology, economics, ecophysiology, epidemiology, genetics, and management sciences. The project brought together scientists from 10 labs, as well as agricultural advisers and farmers from 6 French counties. The project first described the functional diversity of 57 varieties, highlighting the effects of modern breeding on trait variability, that lowered variability of traits subject to direct selection, and impacted both plant architecture, physiological traits as nutrient absorption, but also trade-off between traits. Wheatamix then surveyed how variation in mixture diversity impacted wild communities. A first result highlighted the low abundance of macro-organisms in this experiment: no relationship was found between the number of varieties in a mixture and the diversity/abundance of earthworms, weeds, mycorrhizae, springtails, beetles, nematodes. However, a significant effect of mixture diversity on the abundance of some spiders, and on nitrifying bacteria, was observed. Coming to ecosystem services, disease regulation (rust and septoria) has been confirmed as the most strongly and positively affected by varietal associations, raising also the strong effects of architectural variability of the canopy (septoria). Diversity also contributed to higher predation rates on aphids. Lastly, soil nitrification and denitrification activities were significantly affected by mixture diversity on 4 surveyed sites, contributing to a shift in plant nutrition and positive effect of greenhouse gas emission.Co-design of variety mixtures was carried out with farmers, technical advisers, and scientists. For three years, 30 farmers in the Paris basin proposed varietal blends and measured their performance on their farms. This exchange first highlighted that the first goals for farmers was to i) secure their production ii) simplify plot management. Then co-design workshops allowed to propose assembly rules and design mixtures, resulting in a wide diversity of sown mixtures. Field trials revealed that in more than 70% of the cases, the mixture had a higher yield than the mean of its components. This work highlighted farmers needs and resulted in a Multicriteria Evaluation Tool, helping farmers and advisers to design mixtures. The survey of the wheat supply chain finally highlighted the need for a concerted innovation among the various actors. Finally, Wheatamix also developed new statistical method to infer mixing ability, allowing both to blend the best mixers, and also to propose new breeding methods.Coupling various disciplines and approaches, such as ecophysiological modeling of plant competition (FSPM WALTer), field and controlled experiments, theoretical framework in ecology (sampling vs complementarity effects, functional traits and tradeoff), and mixture co-design and surveys with stakeholders, Wheatamix has allowed to understand the interest of cultivar mixtures for farmers. Wheat cultivar mixtures are experiencing an exponential growth: they only represented 2% of bread wheat sown in 2010, and are presently at 8%, raking at the first position on the cultivar list. Wheatamix emphasizes the need for an interdisciplinary approach when addressing agroecological subjects, and illustrates the strong mutual benefices between agronomic and ecological sciences