Analyse des changements de pratiques, de leurs trajectoires et des performances associées dans les systèmes viticoles du réseau DEPHY

Transition towards low pesticide farming systems is a key issue to improve viticulture sustainability. Farmers have to gradually change their practices to engage in this transition. A large number of agroecological practices are already existing but farmers can encounter obstacles during their implementation.This thesis in agronomy proposes to study the mechanisms of changes of practices over time and their impacts on the dynamics of performance by focusing on winegrowers committed to a pesticide reduction approach, in order to better understand and support the agroecological transition. This work is fundamental to identify the trajectories leading to management strategies associated with low pesticide use in conventional viticulture but also in organic viticulture.It proposes an original approach combining database analysis and surveys of winegrowers involved in the DEPHY network. On the basis of data from the national DEPHY network, an evaluation of the technical, economic and environmental performance of the winegrowers and their trajectories was carried out. These analyses showed that the DEPHY farms reduced their IFT by 33% on average without this reduction affecting yields. In a second complementary part, an analysis of the changes in practices implemented by the winegrowers to reduce inputs and improve their environmental performance was carried out by surveys. We showed that the levers were implemented step by step and were mainly based on efficiency and substitution. The study of practice trajectories allowed the identification of a generic trajectory leading to a reduction of pesticides.The approach proposed during this thesis allowed to produce generic results at vineyard sector scale by combining analyses on a large-scale national database and more specific analyses at the farm level with surveys. The low level of redesign observed raises questions about the support given to winegrowers during their pesticide reduction process, but also about the production of knowledge on innovative practices.La transition vers des systèmes agricoles à faible utilisation de pesticides est une étape clé pour améliorer la durabilité de la viticulture. Les viticulteur·ice·s doivent changer leurs pratiques pour réduire durablement leur utilisation d'intrants. Un grand nombre de pratiques agroécologiques existent déjà mais les agriculteur·ice·s peuvent rencontrer des difficultés lors de leur mise en œuvre.Cette thèse en agronomie propose d'étudier les mécanismes de changements de pratiques dans le temps et leurs impacts sur la dynamique des performances, en focalisant cette étude sur des viticulteur·ice·s engagé·e·s dans une démarche de réduction des pesticides, dans le but de mieux comprendre et accompagner la transition agroécologique. Ce travail est fondamental pour identifier les trajectoires conduisant à des stratégies de gestion associées à un faible usage de pesticides au sein de la viticulture conventionnelle mais aussi au sein de la viticulture biologique.Elle propose une démarche originale combinant analyse de base de données et enquêtes de viticulteur·ice·s engagé·e·s au sein du réseau DEPHY. Sur la base des données du réseau national DEPHY, une évaluation des performances techniques, économiques et environnementales des viticulteur·ice·s et leurs trajectoires a été faite. Ces analyses ont permis de démontrer que les fermes DEPHY réduisaient leur IFT de 33% en moyenne sans que cette baisse n'impacte les rendements. Dans un deuxième volet complémentaire, une analyse des changements de pratiques mis en œuvre par les viticulteur·ice·s pour réduire les intrants et améliorer leurs performances environnementales a été réalisée par enquêtes. Nous avons montré que les leviers étaient implémentés pas-à-pas et reposaient principalement sur de l'efficience et de la substitution. L'étude des trajectoires de pratiques a permis l'identification d'une trajectoire générique conduisant à une réduction des pesticides.L'approche mise en place au cours de ce travail de thèse a permis de produire des résultats génériques à l'échelle de la filière vigne grâce à la combinaison d'analyses sur base de données nationale à large échelle et d'analyses plus spécifiques à l'échelle de l'exploitation suite aux enquêtes. Le faible niveau de reconception observé soulève des questions sur l'accompagnement des viticulteur·ice·s au cours de leur démarche de réduction des pesticides mais aussi sur la production de connaissances sur les pratiques innovantes

Analysis of changes in practices, trajectories and associated performances in the viticultural systems of the DEPHY network

La transition vers des systèmes agricoles à faible utilisation de pesticides est une étape clé pour améliorer la durabilité de la viticulture. Les viticulteur·ice·s doivent changer leurs pratiques pour réduire durablement leur utilisation d'intrants. Un grand nombre de pratiques agroécologiques existent déjà mais les agriculteur·ice·s peuvent rencontrer des difficultés lors de leur mise en œuvre.Cette thèse en agronomie propose d'étudier les mécanismes de changements de pratiques dans le temps et leurs impacts sur la dynamique des performances, en focalisant cette étude sur des viticulteur·ice·s engagé·e·s dans une démarche de réduction des pesticides, dans le but de mieux comprendre et accompagner la transition agroécologique. Ce travail est fondamental pour identifier les trajectoires conduisant à des stratégies de gestion associées à un faible usage de pesticides au sein de la viticulture conventionnelle mais aussi au sein de la viticulture biologique.Elle propose une démarche originale combinant analyse de base de données et enquêtes de viticulteur·ice·s engagé·e·s au sein du réseau DEPHY. Sur la base des données du réseau national DEPHY, une évaluation des performances techniques, économiques et environnementales des viticulteur·ice·s et leurs trajectoires a été faite. Ces analyses ont permis de démontrer que les fermes DEPHY réduisaient leur IFT de 33% en moyenne sans que cette baisse n'impacte les rendements. Dans un deuxième volet complémentaire, une analyse des changements de pratiques mis en œuvre par les viticulteur·ice·s pour réduire les intrants et améliorer leurs performances environnementales a été réalisée par enquêtes. Nous avons montré que les leviers étaient implémentés pas-à-pas et reposaient principalement sur de l'efficience et de la substitution. L'étude des trajectoires de pratiques a permis l'identification d'une trajectoire générique conduisant à une réduction des pesticides.L'approche mise en place au cours de ce travail de thèse a permis de produire des résultats génériques à l'échelle de la filière vigne grâce à la combinaison d'analyses sur base de données nationale à large échelle et d'analyses plus spécifiques à l'échelle de l'exploitation suite aux enquêtes. Le faible niveau de reconception observé soulève des questions sur l'accompagnement des viticulteur·ice·s au cours de leur démarche de réduction des pesticides mais aussi sur la production de connaissances sur les pratiques innovantes.Transition towards low pesticide farming systems is a key issue to improve viticulture sustainability. Farmers have to gradually change their practices to engage in this transition. A large number of agroecological practices are already existing but farmers can encounter obstacles during their implementation.This thesis in agronomy proposes to study the mechanisms of changes of practices over time and their impacts on the dynamics of performance by focusing on winegrowers committed to a pesticide reduction approach, in order to better understand and support the agroecological transition. This work is fundamental to identify the trajectories leading to management strategies associated with low pesticide use in conventional viticulture but also in organic viticulture.It proposes an original approach combining database analysis and surveys of winegrowers involved in the DEPHY network. On the basis of data from the national DEPHY network, an evaluation of the technical, economic and environmental performance of the winegrowers and their trajectories was carried out. These analyses showed that the DEPHY farms reduced their IFT by 33% on average without this reduction affecting yields. In a second complementary part, an analysis of the changes in practices implemented by the winegrowers to reduce inputs and improve their environmental performance was carried out by surveys. We showed that the levers were implemented step by step and were mainly based on efficiency and substitution. The study of practice trajectories allowed the identification of a generic trajectory leading to a reduction of pesticides.The approach proposed during this thesis allowed to produce generic results at vineyard sector scale by combining analyses on a large-scale national database and more specific analyses at the farm level with surveys. The low level of redesign observed raises questions about the support given to winegrowers during their pesticide reduction process, but also about the production of knowledge on innovative practices

Analyse des changements de pratiques, de leurs trajectoires et des performances associées dans les systèmes viticoles du réseau DEPHY

Transition towards low pesticide farming systems is a key issue to improve viticulture sustainability. Farmers have to gradually change their practices to engage in this transition. A large number of agroecological practices are already existing but farmers can encounter obstacles during their implementation.This thesis in agronomy proposes to study the mechanisms of changes of practices over time and their impacts on the dynamics of performance by focusing on winegrowers committed to a pesticide reduction approach, in order to better understand and support the agroecological transition. This work is fundamental to identify the trajectories leading to management strategies associated with low pesticide use in conventional viticulture but also in organic viticulture.It proposes an original approach combining database analysis and surveys of winegrowers involved in the DEPHY network. On the basis of data from the national DEPHY network, an evaluation of the technical, economic and environmental performance of the winegrowers and their trajectories was carried out. These analyses showed that the DEPHY farms reduced their IFT by 33% on average without this reduction affecting yields. In a second complementary part, an analysis of the changes in practices implemented by the winegrowers to reduce inputs and improve their environmental performance was carried out by surveys. We showed that the levers were implemented step by step and were mainly based on efficiency and substitution. The study of practice trajectories allowed the identification of a generic trajectory leading to a reduction of pesticides.The approach proposed during this thesis allowed to produce generic results at vineyard sector scale by combining analyses on a large-scale national database and more specific analyses at the farm level with surveys. The low level of redesign observed raises questions about the support given to winegrowers during their pesticide reduction process, but also about the production of knowledge on innovative practices.La transition vers des systèmes agricoles à faible utilisation de pesticides est une étape clé pour améliorer la durabilité de la viticulture. Les viticulteur·ice·s doivent changer leurs pratiques pour réduire durablement leur utilisation d'intrants. Un grand nombre de pratiques agroécologiques existent déjà mais les agriculteur·ice·s peuvent rencontrer des difficultés lors de leur mise en œuvre.Cette thèse en agronomie propose d'étudier les mécanismes de changements de pratiques dans le temps et leurs impacts sur la dynamique des performances, en focalisant cette étude sur des viticulteur·ice·s engagé·e·s dans une démarche de réduction des pesticides, dans le but de mieux comprendre et accompagner la transition agroécologique. Ce travail est fondamental pour identifier les trajectoires conduisant à des stratégies de gestion associées à un faible usage de pesticides au sein de la viticulture conventionnelle mais aussi au sein de la viticulture biologique.Elle propose une démarche originale combinant analyse de base de données et enquêtes de viticulteur·ice·s engagé·e·s au sein du réseau DEPHY. Sur la base des données du réseau national DEPHY, une évaluation des performances techniques, économiques et environnementales des viticulteur·ice·s et leurs trajectoires a été faite. Ces analyses ont permis de démontrer que les fermes DEPHY réduisaient leur IFT de 33% en moyenne sans que cette baisse n'impacte les rendements. Dans un deuxième volet complémentaire, une analyse des changements de pratiques mis en œuvre par les viticulteur·ice·s pour réduire les intrants et améliorer leurs performances environnementales a été réalisée par enquêtes. Nous avons montré que les leviers étaient implémentés pas-à-pas et reposaient principalement sur de l'efficience et de la substitution. L'étude des trajectoires de pratiques a permis l'identification d'une trajectoire générique conduisant à une réduction des pesticides.L'approche mise en place au cours de ce travail de thèse a permis de produire des résultats génériques à l'échelle de la filière vigne grâce à la combinaison d'analyses sur base de données nationale à large échelle et d'analyses plus spécifiques à l'échelle de l'exploitation suite aux enquêtes. Le faible niveau de reconception observé soulève des questions sur l'accompagnement des viticulteur·ice·s au cours de leur démarche de réduction des pesticides mais aussi sur la production de connaissances sur les pratiques innovantes

Trajectories of technical changes in pesticide reduction across French vineyards

International audienceHigh quantities of pesticides are applied in vineyards. A shift towards pesticide-free cropping systems, grounded in agroecological principles, is imperative for enhancing the sustainability of agriculture. To achieve this objective, farmers need to change their practices (Tittonell 2014). At the farm level, numerous agroecological practices, more or less effective, already exist but they must be combined (Wezel et al., 2014). The implementation of practices is often done step-by-step following a long process (Sutherland et al. 2012). However, winegrowers are facing several lock-ins toward pesticide use reduction. It is important to explore their trajectories to understand how farmers bypassed these lock-ins. This study aims to analyse the diversity of trajectories of technical changes during the pesticide use reduction transition.Our study is based on the DEPHY-Network, a French farm network created to demonstrate the capacity of farms to reduce their pesticide use. We focused on farms that joined the network between 2010 and 2012, analysing a minimum 10-year trajectory and selecting 37 farms from the network using a three-criteria sampling grid for the survey. The criteria included the wine-growing area (Mediterranean, Atlantic, or Northern climate), production mode (conventional or organic farming), and pesticide use trajectory type defined by Fouillet et al. (2023). Cluster 1 corresponds to farms that entered the network with a low TFI and that experienced a low TFI decrease (-16.4%). Cluster 2 corresponds to farms that started with a low TFI and that managed to reduce significantly their TFI (-48.7%). Cluster 3 represents farms with a high initial TFI and a high TFI reduction (-63%).All technical changes related to pesticide use since entering the network were identified and characterized using the “Efficiency (E), Substitution (S), Redesign (R)” (ESR) framework (Hill & MacRae, 1996). Each change was assigned an E, S, R level based on its nature and intensity, and an integrated ESR score of change was calculated each year for each vineyard following Merot et al.'s (2019) methods. We studied each individual trajectory of ESR scores by using Moulin et al. (2008) method, splitting trajectory into agronomic coherence phases. We considered that an integrated ESR score R affected this coherence. After delimiting the coherence phases, the next step consisted of qualifying each coherence phase according to the practices performed into technical combination.From the surveys, we recorded 64 changes implemented by the winegrowers. Major levers included dose reduction, replacement of chemical products with biocontrol and cessation of herbicides under the row. Cluster 2 experienced a higher change in the coherence phase by predominantly redesigning their cropping systems (e.g. conversion to organic farming, ), while Cluster 3 and Cluster 1 Farms primarily implemented levers focused on gaining efficiency (e.g. progressive dose reduction).Our study underscores that the diversity of identified pathways is associated with different implemented levers and the evolution of pesticide reduction. Further analyses are essential to identify the trade-offs between pesticide reduction and other performance indicators (yield evolution) and to characterize the risks undertaken by farmers during the agroecological transition.References:Gliessman, S. (2016). Transforming food systems with agroecology. Agroecology and Sustainable Food Systems, 40(3), 187‑189. https://doi.org/10.1080/21683565.2015.1130765Fouillet, E., Delière, L., Flori, A., Rapidel, B., & Merot, A. (2023). Diversity of pesticide use trajectories during agroecological transitions in vineyards : The case of the French DEPHY network. Agricultural Systems, 210, 103725. https://doi.org/10.1016/j.agsy.2023.103725Hill, S. B., & MacRae, R. J. (1996). Conceptual Framework for the Transition from Conv entional to Sustainable Agriculture. Journal of Sustainable Agriculture, 7(1), 81‑87. https://doi.org/10.1300/J064v07n01_07Merot, A., Alonso Ugaglia, A., Barbier, J.-M., & Del’homme, B. (2019). Diversity of conversion strategies for organic vineyards. Agronomy for Sustainable Development, 39(2), 16. https://doi.org/10.1007/s13593-019-0560-8Moulin, C.-H., Ingrand, S., Lasseur, J., Madelrieux, S., Napoléone, M., Pluvinage, J., Thénard, V., 2008. Comprendre et analyser les changements d’organisation et de conduite de l’élevage dans un ensemble d’exploitations : propositions méthodologiques, in: Dedieu, B., Chia, E., Leclerc, B., Moulin, C.-H., Tichit, M. (Eds.), L’élevage en mouvement. Flexibilité et adaptation des exploitations d’herbivores. Quae, p. 3.Wezel, A., Casagrande, M., Celette, F., Vian, J.-F., Ferrer, A., & Peigné, J. (2014). Agroecological practices for sustainable agriculture. A review. Agronomy for Sustainable Development, 34 (1), 22. https://doi.org/10.1007/s13593-013-0180

Diversity of pesticide use trajectories during agroecological transitions in vineyards: The case of the French DEPHY network

International audienceCONTEXT: Winegrowers apply large quantities of pesticides to their vineyards to reduce high cryptogamic pressure. But these practices must change to lower pesticide use and improve viticulture sustainability. Different options for curbing pesticide use exist, and they can be progressively implemented following a specific temporal scheme in each production system. Some change trajectories can be more efficient than others in limiting pesticide applications. Combining trajectory studies and typology may be helpful in characterizing how farmers change their practices and in summarizing the various production system trajectories possible when transitioning towards pesticide use reduction.OBJECTIVE: The aims of this study were i) to identify different types of pesticide use trajectories, and ii) to understand the options implemented by winegrowers to reduce their pesticide use.METHODS: We analysed data from 161 farming systems in the DEPHY farm network in 12 French winegrowing regions over a 10-year period. Pesticide use was assessed with the treatment frequency index (TFI). We characterized the TFI trajectory of each farming system with six indicators and built a typology of TFI trajectories. We then analysed several indicators such as the use of biocontrol products and the dose sprayed to identify some of the management options chosen to achieve these pesticide use trajectories.RESULTS AND CONCLUSIONS: Three clusters were identified and characterized in terms of pesticide use strategy. The first cluster represented farms with an initial point close to the regional average and which did not experience a significant TFI reduction (−13%). The second cluster comprised farms with a low TFI when entering the network that were able to further reduce their TFI over time (−48%). The last cluster represented farms with a high initial TFI and a high reduction (−63%). All clusters managed to reduce their pesticide use by combining several technical levers at different intensities. Some differences in the levers between clusters were observed. Cluster 2 farms are in the process of converting to organic farming and using the associated levers such as biocontrol and mechanical weeding.SIGNIFICANCE: The changes implemented by cluster indicate a varying degree of progress in the transition towards pesticide use reduction. The initial point was identified as having a strong influence on the end result. The more intensively the technical levers were combined, the more difficult it was to reduce pesticide use. The DEPHY network supported winegrowers in their reduction of pesticides who managed to reduce their pesticide use by 13% to 63%

Less field-level insecticides, but not fungicides, in small perennial crop fields and landscapes with woodlands and organic farming

International audienceCONTEXT A large body of evidence suggests that landscape management may limit the use of pesticides in agricultural systems. However, this hypothesis is largely based on studies about biological pest control service, and the effects of landscape context on pesticide use remain poorly investigated.OBJECTIVEHere, we investigated how the proportion of host crops and semi-natural habitats affected the local use of fungicides and insecticides in the most treated crops in France, i.e., apple orchards and vineyards.METHODSUsing pesticide use information at the national level from 64 apple orchards and 138 vineyards monitored between 2014 and 2019, we investigated how local field size, several aspects of landscape context (proportion of host crops, share of organic host crop, proportion of woodlands and grasslands) as well as the weather context affect the frequency, timing and diversity of local fungicide and insecticide use.RESULTS AND CONCLUSIONSOur results highlight that landscape-scale management could reduce the use of insecticides in agricultural landscapes. In vineyards, a lower use of insecticides was observed in small fields or landscapes composed of a high proportion of woodlands, while in orchards a lower local use of insecticides was found in landscapes with a high share of organic orchards. Fungicide use was mainly affected by the weather context in both apple orchards and vineyards, with more fungicide use in humid and warm weather. However, effects of vineyard size and grassland proportion on the date of the first spray suggest that these two variables may impact pathogen spatial dynamics, a topic that needs further investigations.SIGNIFICANCELandscape-scale management options highlighted in our study may contribute to the design of functional agricultural landscapes minimising pesticide use

Lowering pesticide use in vineyards over a 10-year period did not reduce yield or work intensity

International audiencePesticides remain the most efficient way to control pest and disease pressure in vineyards and obtain satisfactoryyields in terms of quality and quantity. However, because of the harmful effects of pesticides on human healthand the environment, winegrowers have had to change their practices. To reduce pesticide use, winegrowershave a range of levers at their disposal that are implemented at different spatial and temporal scales and withdifferent intensities of change. Beyond simply reducing pesticide use, these changes can also impact farms’economic and social performances notably because vine is a perennial crop with inertia in the impacts of changesoperated. In this work, we assessed the covariation between various performances with time. We used theAgrosyst database, which compiles data on the performances of French vineyard cropping systems engaged in apesticide reduction process for the past 10 years, implementing a reduction of 34%. Based on existing knowledgeon transition processes and pesticide reduction in vineyards, we used partial least squares path modelling (PLSPM)to assess the dynamic trade-offs between different performances during the pesticide use reduction process.We verified the model we built (GoF = 0.44) and found no significant correlation between pesticide reduction,economic performances (operating costs and fuel consumption), technical performance (mechanical work time)or productivity (yield). Interestingly, we did not observe any effect from reducing fungicides on yield. We onlynoticed a significant correlation between the initial weed control strategy and the change in weed controlstrategy (β = 0.18). Furthermore, stopping herbicide use did not affect mechanical work time or costs. Our resultsare encouraging in terms of maintaining both agronomic and economic performances when reducing pesticidesin vineyards

Vers des systèmes viticoles économes en pesticides: Étude du réseau DEPHY-Ferme – Analyse de l’évolution de l’utilisation des pesticides au sein des exploitations du réseau DEPHY

International audienceL’utilisation de produits phytosanitaires (cuivre, soufre et produits de synthèses) est à ce jour le moyen de lutte le plus efficace pour garantir une vendange qualitative et quantitative (Pujol, 2017). Face aux préoccupations sociétales croissantes concernant l’impact des pesticides sur l’environnement et la santé, la viticulture se doit pourtant de réduire sa dépendance aux produits phytosanitaires. Une transition agroécologique est ainsi nécessaire et implique de changer les pratiques afin de parvenir à diminuer l’utilisation des produits phytosanitaires. Le réseau DEPHY-Ferme a été créé en 2010 afin d’initier et stimuler cette transition agroécologique et répondre aux enjeux ambitieux instaurés par le plan Écophyto (loi n° 2009-967) de réduction des produits phytosanitaires de 50 % en 10 ans. Ce réseau couvre les principales filières de productions agricoles (grandes cultures et polyculture élevage, arboriculture, viticulture, maraîchage, horticulture et cultures tropicales). Dans le cas des systèmes viticoles, 450 domaines se sont engagés dans le réseau DEPHY-Ferme vigne. Ils se répartissent sur l’ensemble des bassins viticoles français

Reducing pesticide use in vineyards : Evidence from the analysis of the French DEPHY-Network

International audienc