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What are the critical phenological periods for sustainable perennial grain production in the annual development of intermediate wheatgrass?
No full textInternational audienc
La gouvernance territoriale au prisme du concept de "système alimentaire du milieu"
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Agroecology as farmers’ situated ways of acting : a conceptual framework
No full textInternational audienceThe limits of numerous agricultural systems developed on principles set after the Second World War are increasingly identified and highlighted. Meanwhile, agricultural and food systems associated with agroecological principles are progressively institutionalized in various countries. Whereas a dominant research production by agronomists consists in deduction of “agroecological practices” from fundamental agroecological principles, a gap remains between those principles and the specific management actions on farms that allow to build new agroecological framing systems. In this study, we stem from an analysis of management actions in eight different case studies corresponding to farmers’ collectives engaged in an evolution of their practices towards agroecology. We review the agroecological scientific literature to identify shared principles and system properties deduced from them, that we iteratively compared to the practices implemented by farmers, making the transition in our case studies. Our proposal is then to describe agroecology “in the making” as 4 interconnected ways of acting, each corresponding to specific relations between management actions and the systems’ properties. Lastly, the analysis of agroecology from the actors’ management practices allows us to support a new viewpoint about a research agenda for agronomists, giving reflexive benchmarks to relocate research activities within the institutionalization dynamics of agroecology
French policy for agroecology : development, implementation, and lessons learned
No full textInternational audienc
ALLIANCE: Amélioration des performances écologiques et économiques par association de plantes de services légumineuses dans des systèmes de grandes cultures.
No full textCe volume regroupe les textes issus du programme Casdar "Innovation et Partenariat" et "Recherche finalisée et innovation" de 2013. Le colloque de restitution s’est déroulé le 6 février 2019 sous l’égide du GIS Relance AgronomiqueInternational audienceThe objective of this project was to (1) quantify the ecosystem services provided by the "cash crops - service plants" associations for winter rape and soft winter wheat, and their effects on the following crops in more or less diversified field crops and livestock systems, in conventional and organic agriculture (2) test different cultural practices and tools to accompagny this innovation. This work began with a meta-analysis of experimental results from 34 scientific articles from 17 countries, and showed that companion plants associated with different annual crops lead to a 56% reduction in weed biomass compared to a single unweeded crop, and 42% compared to a weeded crop. Then experiments in agricultural fields and controlled sowing conditions were set up. Concerning rapeseed, frost susceptible species, most often selected among legumes, were sown at the same time as rapeseed to compete with weeds and disturb insects during the fall (Lorin, 2015). As the companion plant does not survive the winter, the rapeseed ends its cycle without competition and benefits from nitrogen released by plant residues. The results of 79 trials conducted in France between 2009 and 2016 validated this technique and assessed the multi-criteria interests of several pipes. The legume plants associated with rapeseed make it possible to reduce fertilization by 30 kg N/ha without yield lost. In organic farming, compared to a post-harvest sowing of wheat, sowing in spring with wheat undercover, allows legumes to grow more quickly once the wheat is harvested. The effects on wheat growth are negligible, whereas weed control was directly related to the biomass produced before the end of summer and will only be effective after the wheat harvest, during intercrop cultivation. A tool, which helps to choose the species to be associated according to agronomic objectives, has been designed using a participatory approach in order to integrate and share existing knowledge on the associations between rapeseed and service plants. The model developed is based on a functional approach that links the traits of candidate species to potential processes and services.L’objectif de ce projet était de (1) quantifier les services écosystémiques rendus par les associations « cultures de rente – Plantes de services » pour le colza d’hiver et le blé tendre d’hiver, et leurs effets sur les cultures suivantes dans des systèmes de grandes cultures stricts (plus ou moins diversifiés) et de polycultures élevages, en agriculture conventionnelle et biologique (2) tester différentes conduites culturales et des outils pour accompagner cette innovation Ce travail a démarré par une méta-analyse de résultats expérimentaux extraits de 34 articles scientifiques couvrant 17 pays, et a montré que les plantes compagnes associées à différentes cultures annuelles conduisent à une réduction de 56% de la biomasse d’adventices par rapport à une culture seule non-désherbée, et 42% par rapport à une culture seule désherbée. Puis des expérimentations en parcelles agricoles et en conditions semis controlées ont été mises en place. Concernant le colza, des plantes de services gélives, le plus souvent choisies dans la famille des légumineuses ont été semées en même temps que le colza pour concurrencer les adventices et perturber les insectes pendant l’automne (Lorin et al., 2015). La plante de services ne survivant pas à l’hiver, le colza termine son cycle sans concurrence et bénéficie d’azote restitué par les résidus de plantes. Les résultats de 79 essais menés en France entre 2009 et 2016 ont permis de valider cette technique et d’évaluer les intérêts multi-critères de plusieurs conduites. Les plantes légumineuses gélives associées au colza permettent à la fois de réduire la fertilisation de 30 kg N/ha sans perdre de rendement. En agriculture biologique, en comparaison à un semis après la récolte du blé, le semis sous couvert au printemps permet aux légumineuses de se développer plus rapidement une fois le blé récolté. Les effets sur le blé sont négligeables, alors que le contrôle des adventices est directement lié à la biomasse produite avant la fin de l’été et ne sera effectif qu’après la récolte du blé, pendant l’interculture. Un outil, permettant d’aider au choix de l’espèce à associer en fonction d’objectifs agronomiques, a été conçu selon une démarche participative afin d’intégrer et partager les connaissances existantes sur les associations colza – plantes de services. Le modèle développé s’appuye sur une démarche fonctionnelle reliant les traits des espèces candidates, aux processus et aux services potentiel
Intérêt de données distribuées de hauteur d'eau et d'humidité du sol pour l'évaluation d'un modèle hydrologique distribué. Application au modèle PUMMA sur le bassin versant du Mercier (6.6 km2) en France
No full text[Departement_IRSTEA]Eaux [TR1_IRSTEA]ARCEAU [ADD1_IRSTEA]Hydrosystèmes et risques naturelsInternational audienceThis paper emphasizes the importance of integrating outlet discharge and observed internal variables in the evaluation of distributed hydrological models outputs. It proposes a general methodology for a diagnostic evaluation of a complex distributed hydrological model, based on discharge data at the outlet and additional distributed information such as water level and surface soil moisture data. The proposed methodology is illustrated using the PUMMA model in the Mercier sub-catchment (6.6 km 2 ). Model parameters are specified according to field data and a previous study performed in a neighbouring catchment (Jankowfsky et al., 2014), without calibration. The distributed water level and soil moisture network of sensors were useful in the model evaluation process. Thus, model parameters are specified either using in situ information or results from previous studies. A stepwise approach is used for model evaluation. It includes standard water balance assessment as well as comparison of observed and simulated outlet discharge, whether on annual or event timescales. Soil moisture sensors are used to assess the ability of the model to simulate seasonal water storage dynamics based on a normalized index. The water level sensors network is used on two timescales: on a seasonal timescale, sensors network is used to assess the model's ability to simulate intermittency; whereas on event timescales, sensors network is used in determining the model's ability to reproduce observed reaction as well as response times. Event timescales do also focus on the correlation between hydrological response and either rainfall event or antecedent soil moisture variables. Results show that the non-calibrated model is quite effective at capturing water flow and soil water-storage dynamics, but it fails to reproduce observed runoff volume during events. There is strong indication of a deficiency in the characterization of catchment storage and upstream flowpath description. The soil water content and a network of water level sensors provide interesting information about soil moisture and river flow dynamics. They however fail to provide quantitative information about catchment storage. This study opens interesting perspectives for the evaluation of distributed hydrological models using hydrological signatures. Furthermore, it highlights the requirement of quantitative as well as qualitative signatures for improving such models
Diversité des trajectoires pour les projets associant développement de l’agriculture biologique et protection de la qualité de l’eau
No full textSelection of Lactobacillus paracasei strains from grated carrots by-products for L-lactic acid production
No full textInternational audienceBeside its utilisation as food preservative, lactic acid can also be used to make biopolymers, or to enter in the composition of cleaning products. Nowadays, different ways are explored to optimize its production. The use of vegetable wastes could appear as a profitable option to reduce costs. In this work, 40 different native lactic acid bacteria isolated from fermented carrot pulps were analysed and compared for their ability to produce lactic acid. The selection relied on the use of two model media, the synthetic Man Rogosa and Sharpe (MRS) medium and a sterilized carrot-like medium. This allowed for the isolation of two interesting species: Lactobacillus paracasei and Lactobacillus harbinensis, which produced high concentrations of L-lactic acid in MRS broth. However, the yield obtained with the carrot-like medium was less important and will have to be optimized in the future. L. paracasei proved to be more interesting than L. harbinensis. In particular, the strain A1L was able to metabolize starch. This ability could be a selective advantage in a complex vegetable matrix to overwhelm the other adventitious microorganisms
Les renouées asiatiques, espèces exotiques envahissantes
No full text[Departement_IRSTEA]TerritoiresInternational audienceAsian knotweeds are part of our landscapes. Introduced in France at the end of the XIXth century, they are now considered among the most threatening species for biodiversity worldwide. This article mobilizes ecologists, geographers, historians and managers in the aim to introduce what we know about these alien invasive species for this special issue. Their ecology is described as well as the history of their invasion, from the first introduction to the change in perception that came with their expansion out of gardens. This article also deals with their numerous impacts and their legal regulation in the French context. Management practices are also described and questioned in the light of a change in paradigm that could help to better take a fresh look at their management.Les renouées asiatiques font partie de nos paysages. Introduites en France à la fin du dix-neuvième siècle, elles sont classées au niveau mondial parmi les espèces exotiques envahissantes les plus menaçantes pour la biodiversité. Cet article, mobilisant écologues, géographes, historiens et gestionnaires, vise à introduire les éléments de connaissance sur ces espèces, sujet de ce numéro spécial et objet de nombreuses recherches et essais de gestion en France, en Europe et dans le monde. Leur écologie est décrite et l'historique de leur introduction abordée, depuis la première importation jusqu'au changement de perception qui a accompagné leur développement incontrôlé en dehors des jardins. Cet article aborde leurs nombreux impacts et fait aussi le point sur la réglementation les concernant au niveau français. Les différentes pratiques de gestion sont également présentées, puis questionnées en conclusion, à la lumière d'un changement de paradigme qui peut apparaître nécessaire à la meilleure gestion de ce « problème »
