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Une analyse des situations d'usage pour concevoir des outils d'aide au changement de pratiques
No full textDéveloppement d'outils d'aide à la décisionCe volume fait suite au carrefour de l'innovation Inrae, organisé par Inrae, Agreenium et l'Institut Agro Dijon, les 26 et 27 novembre 2024 de restitution du projet sur les Connaissances et outils pour des démarches préventives et opérationnelles en gestion agroécologique des adventices (COPRAA).National audiencePour aider les agriculteurs dans leur changement de pratiques, un nombre croissant d'outils sont proposés aux agriculteurs et leurs conseillers. Un des enjeux est d'organiser la conception de ces outils pour qu'ils soutiennent effectivement et efficacement l'activité de celles et ceux qui souhaitent transformer leurs pratiques. Pour y répondre, nous mobilisons une approche fondée sur une analyse de l'activité que l'outil à concevoir doit aider à faire évoluer. Cette analyse met en lumière les « médiations » que l'outil peut contribuer à soutenir entre un acteur et l'objet de son action. A partir de trois projets réalisés (APPI'N, MoCoRiBa, DeciFlorSys), nous montrons les retombées de cette approche sur le processus de conception, en particulier sur : les propriétés de l'outil à concevoir et les médiations qu'il soutient, les formes d'implication des utilisateurs, l'activité des concepteurs
Potential of peatlands restoration for GHG emissions mitigation in France: Investigation of acquisition costs
No full textInternational audiencePublic demand for the restoration of degraded French peatlands is strong, as they contribute to climate change. A French carbon offset accreditation is being developed to facilitate private investment in peatland restoration. Assessing the costs of restoration programs and projects is vital to target cost-efficiency. Studies on acquisition costs are non-existent in the peatland scientific literature, while the sale price of peatlands could increase restoration costs, hampering the feasibility of operation works. Given the need for spatially explicit information for restoration planning, we use the first stage of the hedonic prices method to provide a model that measures the price of French peatlands and its determinants, at a national scale. Real peatland sales from the DVF+ database (Cerema) are exploited. The parcels selected in the model are distributed along a gradient of elevation, state of degradation and intensity of land use. Predictions of peatland prices are then made in the Cotentin-Bessin and jurassian massif regions to check the validity of the model. The average peatland price is 3014 €/ha but it varies greatly between regions. The main results indicate that intensive land use (crops) and increasing slope raise the selling price, while elevation, increasing distance to settlement and moor land use lower it. The prediction results are encouraging for a nationwide use of peatland prices in restoration planning programs. This study will also help get a better understanding of implications of peatland acquisition in restoration and total costs. This study provides ex-ante information before the price of land may rise due to soaring carbon prices and the attractiveness of peatland purchase for private sector following the implementation of the French carbon offset accreditation for peatlands. Afterwards, the focus should be put onto complementary land indicators such as fragmentation. The methods developed in the article can be applied to other contexts where there are overlapping land uses
Les cires de surbouchage : un élément esthétique ou fonctionnel ?
No full textInternational audienceAn in-depth study was carried out to assess oxygen transfer through different waxes and resins, either alone or used in combination with cork-based stoppers. The research provided the answer to a crucial question being asked by many winemakers and consumers: does the application of overcapping wax play a protective role against oxidation of the wine during bottle ageing (Ureña et al., 2024)?Une étude approfondie a été menée pour évaluer le transfert d'oxygène à travers différentes cires et résines, seules, ou utilisées en combinaison avec des bouchons à base de liège. Les travaux ont permis de répondre à une question cruciale que se posent de nombreux vignerons et consommateurs : l'application de cire de surbouchage joue-t-elle un rôle protecteur contre l'oxydation du vin lors de son vieillissement en bouteille
Modes of action and inhibitory activity of Trichoderma species on potato and tomato pathogenic Phytophthora infestans: A review
No full textInternational audienceLate blight, caused by the oomycete Phytophthora infestans, is one of the most devastating diseases of potatoes and tomatoes, resulting in low yields and economic losses for farmers. Trichoderma spp. are known for their antagonistic abilities against a wide range of pathogens, including P. infestans. This review provides an overview of the current knowledge on Trichoderma spp., by (1) classifying the diversity of modes of action of Trichoderma species and (2) assessing the antagonistic ability of several species and strains of Trichoderma spp. against P. infestans in dual culture, through a meta-analysis. We found that many species of Trichoderma spp. have a double action against P. infestans, both (1) direct on the plant pathogen by emitting enzymes and volatile organic compounds and (2) plant-mediated by enhancing the host plant's defence potential. The meta-analysis showed that direct Trichoderma antagonistic ability against P. infestans is species and strain dependant. Among the most effective species, T. asperellum stands out with a mycelial inhibition potential of up to 90% for some strains. These findings were used to build a decision-making system, that accounts for Trichoderma-plant-Phytophthora interactions, pedoclimate, and strategies of Trichoderma spp. application on crops. The paper provides new insights into the management of P. infestans on potato and tomato crops and highlights promising biocontrol or fungicide mixtures, including several Trichoderma spp. and little-known species with promising regulatory effects on P. infestans
Tax Competition With Intermunicipal Cooperation
No full textInternational audienceWe study local tax competition when municipalities can voluntarily cooperate. We compare the intensity of interjurisdictional policy interdependence between competing municipalities within the same "establishment for intermunicipal cooperation" (EIMC) and competing municipalities outside of the cooperative unit. To resolve the endogeneity of the decision to cooperate, we apply the approach of Kelejian and Piras. The strategic response to the average tax rate among peer members of the same EIMC is less intense than the response to the average tax rate of municipalities outside of the cooperative unit. A 1 percentage point decrease in the average tax rate of nonmembers lowers the own-jurisdiction tax rate by 0.58 percentage points, while a 1-unit decrease in the tax rate of towns within the EIMC lowers the own-jurisdiction rate by 0.31 percentage points. Our empirical methods can be used to study strategic interactions within other cooperative groups, including supranational institutions such as the European Union
Organizing the democratic process of transitions : the case of the "Collectif Nourrir"
No full textThis issue deals with organizational innovations for the agroecological transition and sustainable agri-food systems, which took place in March 2024 at VetAgro Sup in Lempdes.International audienceTo face the challenges of climate change and erosion of biodiversity, both organizational and technological innovations are required. The experience of the "Collectif Nourrir", which gathers 54 civil society organizations working on agricultural, environmental and food issues, highlights how to implement organizational innovations that respect a number of principles of democratic participation
A form of organisational innovation in agricultural enterprises and its impact on the greening of practices: the case of collective farms
No full textThis issue deals with organizational innovations for the agroecological transition and sustainable agri-food systems, which took place in March 2024 at VetAgro Sup in Lempdes.International audienceA number of conditions are required for organizational innovation in agricultural enterprises. Using the example of a recently-established collective farm, the text explores the various organizational innovations that have been introduced to promote the sustainability of the agri-food system
Simulation-based study of the influence of particle physical properties on fertilizer spreading ability
No full textInternational audienceDespite spreader performance, different fertilizers are known to have inherent limitations that prevent them from achieving the same working width at a targeted spreading quality. Nevertheless, there is currently no mathematical relationship to express the maximum working width achievable by a fertilizer as a function of its physical properties. The aim of this paper is to develop a numerical method to provide such a mathematical relationship. Since the maximum working width WWCV10 ensuring a satisfying uniformity (CV≤10%) is a complex parameter (resulting from different stages of the spreading process), the issue has been decomposed into two steps. First, a dataset is computed by numerical simulations. 3800 virtual fertilizers are designed and feed into numerical simulations based on a Monte Carlo process. For each fertilizer, twin disk spread patterns are computed for a set of virtual spreader settings. Then, WWCV10 is deduced from simulations of adjacent passes and overlaps. The mean radius Rm of the spread pattern is also computed. Second, based on this consistent dataset, multivariate polynomial regressions are established to express WWCV10 and Rm as mathematical functions of 5 independent physical characteristics of the fertilizer: the drag coefficient, the specific density and three particle size distribution parameters. Thus, for the first time, the contribution of each variable (to the ability of the fertilizer to achieve a working width) is quantified and the sensitivity of WWCV10 and Rm is analyzed by using partial derivatives. The correlation between WWCV10 and Rm is also demonstrated
Climate and management changes over 40 years drove more stress‐tolerant and less ruderal weed communities in vineyards
No full textInternational audienceSpontaneous plant communities have undergone considerable constraints due to human‐mediated changes. Understanding how plant communities are shifting in response to land management and climate changes is necessary to predict future ecosystem functioning and improve the resilience of managed ecosystems, such as agroecosystems. Using Mediterranean weed communities as models of managed plant communities in a climate change hotspot, we quantified the extent to which they have shifted from the 1980s to the 2020s in response to climate and management changes in vineyards. The weed communities of the same 40 vineyards in the Montpellier region were surveyed using the same protocol in spring, summer, and autumn, for two years, with a 40‐year interval (1978–1979 vs. 2020–2021). In four decades, the annual range of temperatures (i.e., the difference between the warmest month's and the coldest month's mean temperatures) increased by 1.2°C and the summer temperatures by 2°C. Weed management diversified over time with the adoption of mowing that replaced the chemical weeding of interrows. Chemical weeding is now mostly limited to the area under the row. Current weed communities were 41% more abundant, 24% more diverse, and with a less even distribution of abundance across species than the 1980s communities at the vineyard level. Modern communities were composed of more annual species (57% of annual species in the 1980s vs. 80% in the 2020s) with lower community‐weighted seed mass and were composed of fewer C4 species. They had higher community‐weighted specific leaf area, higher leaf dry matter content, and lower leaf area than the 1980s weed communities. At the community level, the onset of flowering was earlier and the duration of flowering was longer in the 2020s. Climate change induced more stress‐tolerant communities in the 2020s while the diversification of weed management practices favored less ruderal communities. This study shows that plant communities are shifting in response to climate change and that land management is a strong lever for action to model more diverse and eventually more desirable weed communities in the future
