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International audience; By guaranteeing a remunerative price and marketing to farmers in the Niayes area, ASD markets help to dissipate the uncertainty and risks associated with marketing conditions. Our work has allowed us to place the alternative aspect of the ASD market phenomenon, as an original short food marketing circuit based on ethical principles, in a more general context - that of the increasing industrialization and standardization of food production, distribution and consumption. It appears that, under the fire of trade globalization, this question of social demand - which was nevertheless characteristic of Western societies in the northern hemisphere - is gradually gaining ground in a number of emerging societies in the South. New food behaviors are emerging. Henceforth, the urban demand requires healthy and more tasty products.; En garantissant un prix et une mise en marché rémunérateurs aux paysans de la zone des Niayes, les marchés ASD contribuent à dissiper l’incertitude et les risques liés aux conditions de commercialisation. Notre travail nous a permis d’inscrire l’aspect alternatif du phénomène des marchés ASD en tant que circuit court de commercialisation alimentaire original basé sur des principes éthiques, dans un contexte plus général – celui de l’industrialisation et de l’uniformisation croissantes des modes de production, distribution et consommation alimentaires. Il appert que, sous le feu de la mondialisation des échanges, cette question de la demande sociale – qui était pourtant caractéristique des sociétés occidentales de l’hémisphère nord – prend progressivement de l’ampleur dans un ensemble de sociétés émergentes du Sud. Il s’esquisse alors de nouveaux comportements alimentaires. Désormais, la demande citadine requiert des produits sains et plus savoureux.

International audience; Continental carbon (C) sequestration plays a major role in climate change resilience, mitigation, and agro-ecological intensification. Soil Moisture Active Passive Global Daily Carbon Net Ecosystem Exchange dataset (SMAP L4) is used for monitoring daily terrestrial C stocks, given the high potential of semiarid areas for Sustainable Goals achievements, in terms of human issues and surface areas. Inter-and intra-annual variation of Global Primary Productivity (GPP), Net Ecosystem CO2 Exchange (NEE), Soil Heterotrophic Respiration (RH) and Soil Organic Carbon (SOC) were analyzed from 2015 to 2020, across the region of Maradi (Niger) and 15 sites with rainfed crops and vegetal mosaics. To quantify temporal trends of C indicators across years, Mann-Kendall were conducted based on yearly GPP days of min/max. It underlined declines of SOC in the northern part of Maradi (τ >-0.6), rising in the south (τ > +0.6). Univariate monitoring (e.g. 2162 daily measurements) of GPP and RH showed asymmetries in their distribution (positive skews, GPP ̅ =1.19 gC m-2 d-1 , Me=0.88 gC m-2 d-1 ; RH ̅ =0.679 gC m-2 d-1 ; Me=0.485 gC m-2 d-1). This result might be attributed to local variations of Plant Functional Types and microbial activities. Averaged NEE stressed a slightly negative C balance among sites (overall ̅ =-0.003 gC m-2 d-1), suggesting their storage capacity. Processing aspects being set up, a consolidation of those first results should be done. Satellite data records analysis argue for the implementation of Man-Environment observatories in Maradi as a pilot region, for both remote and local understanding of C behavior in agroecosystems and multiscale counseling.

International audience; For professionals who work with and for others and whose activities and situations evolve and are not yet stabilized, one of the challenges is that of reconstructing, with their beneficiaries, the purpose of their activities and of reconfiguring their work situations. This is the case for agricultural advisors who are in the position of accompanying farmers in a change of practices in order to cope with environmental problems. A system was designed to support exchanges between advisors so that they can collectively rethink the efficacy of their action, and dare to act differently. We conducted a participatory observation within this system. We studied the way in which, individually and collectively, the participants grasp the two “milieus” designed by the facilitators in relation to an emblematic advisory situation for crop production: the field tour. Our illustrations and analyses show the different ways that the advisors grasp the developmental potential of these designed situations in order to change their own activity in real work situations. We discuss the professional development that this creates. Finally, we highlight possible avenues for improving the facilitation work to better cope with the diversity of the participants and of their workplace.; Les professionnels qui agissent avec et pour autrui, dont les activités et situations évoluent et ne sont pas stabilisées, ont pour enjeu de reconstruire avec leurs bénéficiaires le sens à donner à leurs activités et aux situations de travail conjointes. C’est le cas des conseillers agricoles mis en situation d’accompagner des agriculteurs dans une évolution de leurs pratiques pour répondre à des problématiques environnementales. Un dispositif d’échange entre pairs a été mis en place auprès de ces professionnels, réunis pour penser collectivement ce qui rend leur action efficace aujourd’hui et pour tenter d’autres pratiques, pour oser faire autrement demain. Nous avons réalisé une observation participante au sein de ce dispositif. Nous étudions plus particulièrement la façon dont, collectivement et individuellement, les participants se saisissent de deux « mises en milieu » conçues par les animatrices du dispositif autour d’une situation emblématique du conseil en production végétale : le tour de plaine. Nos descriptions et analyses montrent la façon différenciée dont les conseillers s’approprient le potentiel de développement des situations ainsi créées pour changer leur activité en situation réelle de conseil. Nous discutons du développement professionnel que cela traduit et pointons des pistes d’améliorations possibles de l’animation pour mieux intégrer la diversité des participants et de leur environnement de travail.

Ozone (O3) is a greenhouse gas and an air pollutant that can, at high concentrations, significantly impact the growth and productivity of agricultural and forest ecosystems. However, the sensitivity of plants to O3 differs according to their ecophysiological, morphological and biochemical characteristics. In my PhD work, I have sought to improve our understanding of resistance of tomatoes to ozone, in particular through the properties of trichomes which are reservoirs of VOCs capable of reacting with ozone. The research strategy consisted in analyzing the variability of VOC emissions and their origins in the 8 parent genotypes of the MAGIC TOM population with high genetic variability. This study mainly highlighted the low constitutive emissions of tomato. It was followed by micro-morphological and histochemical analysis of trichomes on parents and their associated mutants to analyze their role in ozone depletion and plant resistance. Wild parents and their associated mutants were contrasted in trichome composition, morphology, type and density. I have measured the main ozone deposition (cuticular, stomatal, and chemical) through the gas-phase reaction of VOCs with ozone. Plant responses to oxidative stress were measured through changes in photosynthesis, stomatal conductance, Fv/Fm ratio and quantification of visible damage, as well as measurements of VOC emissions during and after exposure to different ozone concentrations. Plant responses differed according to the phenotypes analyzed. Overall, photosynthetic falls, VOC LOX were formed and physical damages were observed in response to oxidative stress. Our results underline the weak role of VOCs in ozone destruction by gas phase reaction and outline the role of the density of glandular and non glandular trichomes in plant resistance. In addition, the resistance to ozone observed in a mutant deficient in numerous monoterpenes and sesquiterpenes suggests that other secondary metabolites with high reactivity and ability to cope with oxidative stress are involved. The results allowed to discuss the role of trichomes and constituent VOCs of tomato plants in O3 destruction. Comparison of mutants and wild relatives with distinct trichomes and VOC emissions is a relevant approach to assess the protective power of these traits against ozone. Indeed, better exploitation of trichomes and secondary metabolites (VOCs and CONVs) in plant production could lead to increased plant resistance to oxidative stress.Keywords: Ozone, tomato, VOC, monoterpenes, sesquiterpenes, oxidative stress, ozone deposition, glandular trichomes.; L'ozone (O3) est un gaz à effet de serre et un polluant atmosphérique, qui peut, à concentrations élevées, avoir des conséquences importantes sur la croissance et la productivité des écosystèmes agricoles et forestiers. Cependant, la sensibilité des plantes à l’O3 diffère en fonction de leurs caractéristiques écophysiologiques, morphologiques et biochimiques. Dans mon travail de thèse, j’ai cherché à améliorer notre compréhension des traits de résistance de la tomate à l’ozone, notamment à travers les propriétés des trichomes qui sont des réservoirs de COV capables de réagir avec l’ozone. La stratégie de recherche a consisté à analyser la variabilité des émissions des COV et leurs origines chez les 8 génotypes parents de la population MAGIC TOM présentant une grande variabilité génétique. Cette étude a souligné le faible taux d’émissions constitutives chez la tomate. Elle a été suivie d’analyses micromorphologique et histochimique des trichomes sur des parents et leurs mutants associés pour analyser leur rôle dans la destruction d’ozone et la résistance des plantes. Les parents sauvages et leurs mutants associés étaient contrastés en composition, morphologie, type et densité de trichomes. J’ai mesuré les principaux dépôts d’ozone (cuticulaire, stomatique, et chimique) à travers la réaction des COV avec l’ozone en phase gazeuse. Les réponses des plantes au stress oxydatif ont été mesurées par des changements de la photosynthèse, de la conductance stomatique, du ratio Fv/Fm et par la quantification des dommages visibles, ainsi que par des mesures des émissions de COV et de leurs teneurs pendant et après l’exposition à différentes concentrations d’ozone. Les réponses des plantes différaient selon les génotypes. Globalement il a été observé en réponse au stress oxydatif, une diminution de la photosynthèse, la formation de COV LOX et des lésions physiques. Nos résultats soulignent le faible rôle de la destruction d’ozone par réaction avec les COV en phase gazeuse et le rôle de la densité des trichomes glandulaires et non glandulaires dans la résistance des plantes. En outre, une certaine résistance à l’ozone observée chez un mutant déficient en nombreux monoterpènes et sesquiterpènes suggère que d’autres métabolites secondaires ayant une forte réactivité et capacité à faire face au stress oxydatif sont impliqués. Les résultats ont permis de discuter le rôle des trichomes et des COV constitutifs des plantes de tomates dans la destruction de l'O3. La comparaison des mutants et des parents sauvages ayant des trichomes et des émissions de COV distincts est une approche pertinente pour évaluer le pouvoir protecteur de ces traits contre l’ozone. De fait, une meilleure exploitation des trichomes et des métabolites secondaires (COV et CONV) en production végétale pourrait permettre une résistance accrue des plantes face au stress oxydatif.Mots clés : Ozone, tomate, COV, monoterpènes, sesquiterpènes, stress oxydatif, dépôt d’ozone, trichomes glandulaires.

Sociological research in France concerning farm advisory services has favoured the study of public agricultural services. Private agricultural advisory services have attracted attention just recently (Compagnone et al. 2015). This dissertation, funded by the agricultural cooperative Terrena (CIFRE), aims at reducing this discrepancy by focusing on the recomposition of technical sales advisors (TSA) occupation. This survey in immersion in the cooperative, between 2015 and 2018, is based on various materials: a participant observation of internal meetings, an ethnographic survey carried out within TSA teams in plant production and animal nutrition, a series of semi-structured interviews carried out with 33 TSA and 22 farmers, and a survey questionnaire sent to the 161 TSA of the cooperative. The study of this professional group (Demazière, Gadea, and Arborio 2009) begins with a sociohistory of farm advisory occupations. It shows that the TSA emerge within agricultural cooperatives to offer farmer members individualized advice, oriented towards qualitative and quantitative control of productions, taking up the repertoire of action of farm advisers. The survey reveals that TSA have a social background frequently and strongly linked to agriculture, and long careers in the cooperative. The rationalization of their recruitment process tends to tighten the access and definition of the occupation on its commercial dimension. The microsociological analysis of the daily work of TSA reveals how the cooperative formalizes knowledge and develops equipment (Vinck, 2009) to control and support the prescription activity of TSA, but also how TSA distances themselves from the cooperative to build and maintain a stable and lasting relationship to farmers. Although TSA share a set of common traits, we reveal four forms of professionalism (Freidson 2013) within the professional group: Experts, Partners, Salesmen and Civics. At the crossroads of sociology of professions and sociology of organizations, this work then proposes a reflection on the recomposition of the TSA occupation, between the cooperative’s controlling regulation effort and the occupational group’s autonomous regulation effort (Reynaud 1988). We show that TSA are stuck between two roles assigned respectively by the cooperative and the farmers, generating tension in their activity. These tensions are related to contradictory technical, relational and commercial instructions addressed to them by the cooperative and farmers, but also to their various professionalizing intentions. As a stakeholder in these worlds, we show that the occupational group defines itself as an intermediary between the cooperative and farmers, depositary of their trust to guarantee their respective interests, interpreting their various logics of action. The thesis opens the discussion on the weight of users in the regulation of service occupations, on the impact of digitization on farmer members, on the role of TSA in the agro-ecological transition, and on the contribution of the CIFRE thesis status to sociological research., Les travaux français de sociologie sur le conseil agricole ont privilégié l’étude des conseillers des chambres d’agriculture et n’interrogent que depuis très récemment les métiers du « conseil privé», dont ceux des coopératives agricoles (Compagnone et al. 2015). Cette thèse CIFRE contribue à rétablir cet équilibre et analyse les recompositions du métier de technico-commercial dans la coopérative agricole polyvalente Terrena. Cette enquête en immersion dans la coopérative, entre 2015 et 2018, repose sur des matériaux variés : observation participante de réunions internes, enquête ethnographique conduite au sein d’équipes technico-commerciales en productions végétales et nutrition animale, entretiens semi-directifs réalisés avec 33 technico-commerciaux et 22 agriculteurs, et un questionnaire d’enquête adressé aux 161 technico-commerciaux de la coopérative. L’étude de ce groupe professionnel (Demazière, Gadea, et Arborio 2009) commence par une sociohistoire des métiers du conseil, qui montre que le métier de technico-commercial émerge au sein des coopératives agricoles dans le but de proposer aux adhérents un conseil individualisé et orienté vers la maîtrise qualitative et quantitative des productions, reprenant le répertoire d’action des conseillers agricoles. L’enquête révèle que les technico-commerciaux présentent une formation et une origine sociale en lien fréquent et fort avec l’agriculture, qu’ils réalisent des carrières longues dans la coopérative et que la rationalisation de leur processus de recrutement tend à resserrer l’accès et la définition du métier sur sa dimension commerciale. L’analyse microsociologique du travail quotidien des technico-commerciaux fait apparaître la façon dont la coopérative formalise les savoirs et développe des équipements (Vinck, 2009) pour contrôler et appuyer l’activité de prescription des technico-commerciaux, mais aussi la façon dont les technico-commerciaux se distancient de la coopérative pour construire et entretenir un lien stable et durable avec les agriculteurs. Bien que les technico-commerciaux partagent un ensemble de traits communs, nos analyses révèlent quatre formes de professionnalités (Freidson 2013) qui coexistent au sein du groupe professionnel : les Experts, les Partenaires, les Commerciaux et les Civiques. A la croisée de la sociologie des groupes professionnels et de la sociologie des organisations, ce travail propose ensuite une réflexion sur la recomposition du métier de technico-commercial, entre une régulation de contrôle exercée par la coopérative et la régulation autonome du groupe professionnel (Reynaud 1988). Nous montrons que les technico-commerciaux se situent entre deux rôles assignés respectivement par la coopérative et les agriculteurs, source de tensions dans leur activité. Ces tensions reposent sur des impératifs techniques, relationnels et commerciaux contradictoires qui leur sont adressés par la coopérative et les agriculteurs, et sur les intentions professionnalisantes différentes qu’ils portent envers le métier de technico-commercial. Partie prenante de ces mondes, nous montrons que le groupe professionnel définit lui-même son rôle comme celui d’un intermédiaire entre la coopérative et les agriculteurs, dépositaire de leur confiance pour garantir leur intérêt respectif, se faisant l’interprète des logiques d’action différentes auxquelles il est confronté. La thèse ouvre une discussion sur le poids des usagers-clients dans la régulation des métiers du service, sur les effets de la digitalisation du service aux adhérents, sur le rôle des technico-commerciaux dans la transition agro-écologique, et sur l’apport du statut de thèse CIFRE pour la recherche en sociologie.

L’intelligence des plantes met l’intelligence artificielle au défi de répondre de façon adaptée aux enjeux de la transition écologique et du changement climatique. L’approche éthico-biologique adoptée ici considère la portée d’une redéfinition de la vie végétale entre « dignification » subjective et conditionnement numérique. L’intelligence des plantes suppose qu’on leur reconnaisse une capacité à poursuivre leurs propres fins, et donc une entéléchie. Elle en appelle à notre propre intelligence pour interpréter avec précision la cohérence organisée et orientée des mouvements morphiques de métamorphose. Ce qui ne peut être calculé exige notre participation dans de nouvelles pratiques éthico-esthétiques où la relation avec les plantes représente une forme d’écosophie indispensable au déploiement de l’agro-écologie., Plant intelligence challenges artificial intelligence to respond appropriately to the issues of ecological transition and climate change. The ethical-biological approach adopted here considers the scope of a redefinition of plant life between subjective “dignification” and digital conditioning. The intelligence of plants presupposes that they are recognized as having an ability to pursue their own ends, and thus possess an entelechy. It compels our own intelligence to interpret precisely the organized and oriented coherence of morphic metamorphosis movements. What cannot be calculated requires our participation in new ethical-aesthetic practices where the relationship with plants represents a form of ecosophy indispensable for the deployment of agro-ecology., Interfaces numériques, 9(1), -1

International audience; The relationship between agriculture and biodiversity divides opinion among farmers. Our research proposes to describe and interpret these opinions, with regard to the diversity of the social backgrounds of the producers, with the hypothesis that interactions with local, non-agricultural individuals help shape these opinions. From 14 interviews carried out with farmers engaged in actions to preserve biodiversity in three territories in the West of France, we identify four different occupational conceptions, characterized by knowledge and taking natural entities into account, through the values and vision of the role that farmers intend to play with regard to biodiversity and way in which they would like this issue to be handled by society. While the role of peer networks in the construction of job conceptions is well established, our research shows that understanding the attitudes of agricultural professionals today requires a consideration of the role that experience and interactions with those outside the agricultural professional sphere play.

International audience; The relationship between agriculture and biodiversity divides opinion among farmers. Our research proposes to describe and interpret these opinions, with regard to the diversity of the social backgrounds of the producers, with the hypothesis that interactions with local, non-agricultural individuals help shape these opinions. From 14 interviews carried out with farmers engaged in actions to preserve biodiversity in three territories in the West of France, we identify four different occupational conceptions, characterized by knowledge and taking natural entities into account, through the values and vision of the role that farmers intend to play with regard to biodiversity and way in which they would like this issue to be handled by society. While the role of peer networks in the construction of job conceptions is well established, our research shows that understanding the attitudes of agricultural professionals today requires a consideration of the role that experience and interactions with those outside the agricultural professional sphere play.

Bee declines, driven by a combination of stressors including pesticides, pathogens and lackof flowers, may exacerbate biodiversity loss and food insecurity. Beekeepers, scientists andpolicy-makers have particularly implicated neonicotinoid insecticides, which are frequentlyfound in the pollen and nectar of crops and weeds. However, the effects of pesticides haverarely been assessed on free-foraging bees in agricultural landscapes.Therefore, we examine, in this thesis, how organic farming impacts honeybee colonies tosee whether they benefit from a farming system without synthetic pesticides. Then, weassess how exposure to the neonicotinoid clothianidin in oilseed rape affects theperformance and pathogen susceptibility of honeybee and bumblebee colonies. Lastly, weexamine neonicotinoid residues in oilseed rape nectar to determine conditions that favourneonicotinoid spread and uptake as well as potential risks for foraging bees.Our results suggest that organic farming may benefit honeybee colonies, possibly througha continuous provision of flowers partially resulting from reduced herbicide use.Clothianidin exposure had no detectable negative impacts on honeybee colonies butsevere effects on the reproduction of bumblebees. Clothianidin exposure barely affectedthe pathosphere of honeybees and bumblebees, suggesting no major long-lastingimmunosuppression. Finally, we determined that, despite being banned in bee-attractivecrops, imidacloprid contamination in oilseed rape poses a risk for foraging bees. Therefore,we reaffirm the recent decision to ban imidacloprid, clothianidin and thiamethoxam in alloutdoor crops in the EU., Les abeilles sont en déclin, menacés par une combinaison de facteurs tels que lespesticides, les pathogènes et le manque de fleurs. Les apiculteurs, scientifiques etpolitiques ont particulièrement incriminé les insecticides néonicotinoïdes, fréquemmentretrouvés dans le pollen et le nectar des plantes cultivées ou sauvages. Cependant, leursimpacts sont rarement évalués sur des abeilles butinant en plein champ.Dans cette thèse, nous regardons si la surface en agriculture biologique autour des ruchesaffecte des abeilles domestiques, pour vérifier si un système de culture sans pesticide desynthèse leur est bénéfique. Puis, nous testons comment les colzas traités au clothianidine,un néonicotinoïde, affectent les performances et la sensibilité aux pathogènes des abeillesdomestiques et des bourdons. Enfin, nous identifions les conditions qui modifient laquantité de néonicotinoïdes dans le nectar de colza et si cette quantité peut potentiellementmenacée les butineuses.Nos résultats suggèrent que l’agriculture biologique peut être bénéfique aux coloniesd’abeilles, probablement grâce à une quantité continue de fleurs dans le temps venantpartialement de l’absence de désherbants. L’exposition à la clothianidine affectaitfortement la reproduction des bourdons, mais peu les performances des colonies d’abeillesdomestiques et la pathosphère des deux espèces. Enfin, de quantités d’imidaclopride, avecun risque considérable pour les butineuses, ont été retrouvées dans le nectar malgrél’interdiction dans les cultures mellifères. Ces résultats confortent la récente décisiond’interdire l’imidaclopride, clothianidine et thiamethoxame en plein champ sur les culturesen Europe.

Public authorities announced the agroecological transition as a major turning point to come for agriculture. At the same time, consumers and civil society are more and more aware of food and agricultural issues. The environmental dimension of the agricultural production seems to strongly gain in importance. The agriculture of the Île-de-France region is dealing with these new injunctions in a context of well-established field crops on a territory facing high stakes (regarding food, the environment, the economy and land planning). What form does this agroecological transition take, what impacts will this transition have for the farmers of Île-de-France and how do these changes lead to new territorial configurations: here are some of the issues that drive this doctoral research.; La transition agroécologique est annoncée par les pouvoirs publics comme le tournant majeur à venir de l’agriculture. Dans le même temps, les consommateurs et la société civile se montrent plus soucieux de l’alimentation et des questions agricoles. La dimension environnementale de la production agricole semble prendre une importance de plus en plus forte. L’agriculture francilienne doit alors composer avec ces nouvelles injonctions agricoles dans un contexte de grandes cultures implantées sur un territoire aux multiples enjeux (alimentaires, écologiques, économiques et d’aménagements). Quelle(s) forme(s) prend la transition agroécologique, quel(s) impact(s) a-t-elle sur les agriculteurs franciliens et la composition des exploitations, en quoi ces changements agricoles peuvent-ils amener à de nouvelles compositions territoriales : voici quelques-unes des questions qui animent et articulent ce travail doctoral.

International audience; In this paper, we explore the awakening potentialities of original open-ended creative approaches inspired by phenomenology, built on sensitive experiences, for teaching agro-ecology. The experiment was conducted in France, within an INRA’s experimental farm station between 2016 and 2018 with more than 1200 visitors, mainly agricultural students and farmers. We designed and tested original multi-modal inquiry tools (mime, landscape drawing, land art and poetry) in order to awake senses, arouse curiosity to learn diversity and communicate different sensitivities. We found that bringing together sensorial perceptive experiences into dialogic spaces, could favour genuine experience sharing and enable to overcome pre-established categories and to transform the operative and epistemic predicates that support conventional agricultural practices. This study opens new perspectives for the design for agricultural field trips on station or agroecological commercial farms. More generally it calls for the development of a “linked” pedagogy, outdoor, sensitive, and creative with a greater consideration of intuitive reasoning, for the (re)-design of sustainable agricultural systems.

Since 2012, the French agricultural sector is enjoined to move towards Agroecology. Also what Agroecology means is controversial, most of the farmers’ consultancy organizations now recognize that it implies : (i) to deliver a more systemic and strategic advice for farmers; (ii) to become involved in multi-stakeholders settings to foster innovation in agri-food systems or/and to manage natural resources. The Chambres of Agriculture took on board these new challenges: new service packages were proposed to farmers, and consultants were committed to their delivery without a clear-cut definition of the required skills to achieve this. The range of change required to deliver such services being often underestimated, the consultants felt unskilled and lost confidence in their own ability to deliver a relevant advice. In a former study, we proposed a didactic intervention (Cerf et al., 2010) to support consultants in developing new skills at individual and team level. We then proposed to various consultancy organizations to identify some consultants who will, within their own organization, act as a designer and a facilitator of such a didactic intervention within their workplace.In this paper, we will present the main features of a didactic intervention carried on by two consultants who designed it and facilitating the exchanges among their own peers in the Burgundy Region. This intervention took place over three years during two-day meetings, twice a year. Ten advisors, hired by the local Chambres of Agriculture, joined these meetings. First we will explain how the didactic intervention was organized into sequences which purposes were: (i) to challenge the current routines and to support advisors in developing their ability to become transition facilitators; (ii) to give them an opportunity to collectively design the way to perform this new role and discuss their professional norms. Second, we will analyze the discussions which took place during the meetings to point out how the collective explores the coupling between a given consultancy situation and the consultant’s performance in this situation (activity analysis). Third, we will give evidence of the professional development which took place during this didactic intervention, whether at individual or collective level. At individual level, we will show various trajectories of professional development and the place the didactic intervention played in such trajectories. We will show the role played by key resources in supporting the individual and collective professional development : (i) the didactic situations proposed by the facilitators, (ii) the discussions held in the collective to carry on the activity analysis (iii) the support offered by the collective to dare new ways to act. Individual professional development occurs on the long run: it depends upon the room to maneuver given by the organization to the consultant and the ability of the last one to identify them. At collective level, routines are discussed and consultants progressively build together a new job identity. To conclude, we will discuss the relevance of such a didactic intervention at workplace and the new role taken by those who design and facilitate this intervention in their own organization.

International audience; This paper presents a social experiment (2016–2018) on an experimental farm station (eastern France), certified in organic farming since 2004, to support the agro-ecological transition by exploring new ways of producing, capitalising and sharing knowledge and experiences. One thousand participants (students in technical programmes and higher education, farmers and Agricultural Knowledge and Innovation System actors) were received to discover and exchange on the autonomous farming system experiment with the practitioners. A learning device mixing innovative learner-centred approaches (phenomenology, dialogue, problem based learning, tactile space, etc.) was de signed, implemented and evaluated. The farm practitioners drew on different resources (storytelling, photos, facts and figures, graphs, markers, indicators from everyday life), and various situations to reflect environmental and work conditions (fields, nearby animals, the milking parlour). A diversity of knowledge, values and experiences were presented, as well as pragmatic research, science in the making, living, unpretentious to restitute complexities, variabilities and uncertainties inherent to autonomous farming system. The issues focus more often on the process, experiences and changes in visions and attitudes than on numbers and figures that are site specific. Intellectual, social, technical and material pathways are made visible and reveal unresolved issues, difficulties, mistakes and unexpected levers, seen as potentially useful resources for diverse end users. The farm station, as a tactile space where knowledge is embedded and embodied, nurtures new intelligibilities. The study shows interesting learning outcomes among participants, who leave with increased knowledge on autonomous farming systems. On evaluation forms, 65% of the respondents declared that they intended to use the knowledge gained.

International audience; The paper analyzes the trajectory of agro-ecology policies in Brazil. It is based on a longitudinal historical analysis of tsocial movements’ actions and the government responses at the Federal level. The methodology includes an extended literature review and interviews with key actors based on a guideline that drew from the sociology of public action theoretical framework. Results indicate that the formation of a coalition of social movements has played a major role in the adoption of the national policy for agro-ecology and organic production. The design and implementation of this policy are based on a series of participatory and intersectoral mechanisms. The change of government in 2016 has blocked this process, but other dynamics can be anticipated at the local level.Keywords: Public policies; social movements; agro-ecology; organic agriculture; Brazil; L’objectif de la communication est double. Elle vise d’abord à examiner le processus historique qui a permis de placer l’agroécologie dans l’agenda des politiques publiques. En second lieu, il s’agit d’analyser les controverses, débats et luttes entre les différents acteurs porteurs d’un projet visant à définir et institutionnaliser un modèle agricole alternatif au modèle agricole dominant issu de la révolution verte.Cet objectif s’inscrit dans un débat particulièrement marqué au Brésil depuis une vingtaine d’année autour des aspirations de changements de trajectoire des politiques agricoles (Petersen, 2013). En effet, malgré la capacité innovatrice du pays à mettre en oeuvre des politiques de développement rural qui tentent de faire émerger un modèle agricole alternatif, le modèle de l’agrobusiness est resté largement dominant. Dans ce contexte, l’institutionnalisation apparente de l’agroécologie est-elle porteuse d’un changement de trajectoire des politiques publiques de développement rural au Brésil ? La communication se divise en quatre parties. La première présente brièvement le cadre théorico-méthodologique mobilisé, fondé sur des approches de sociologie de l’action publique. La seconde présente le contexte économique, politique et institutionnel qui caractérise la dualité des modèles agricoles au Brésil, et dans lequel l’agroécologie s’est progressivement insérée. La troisième examine le jeu d’acteurs qui a conduit à placer l’agroécologie au coeur du débat public, puis dans l’agenda politique. La quatrième section est consacrée à la construction des politiques publiques visant à renforcer l’émergence d'un ensemble d'instruments d'action gouvernementale pouvant être mobilisés en faveur de l'agroécologie. Enfin, la conclusion fait le point sur l’état de la mise en oeuvre de ces instruments.

International audience; The paper analyzes the trajectory of agro-ecology policies in Brazil. It is based on a longitudinal historical analysis of tsocial movements’ actions and the government responses at the Federal level. The methodology includes an extended literature review and interviews with key actors based on a guideline that drew from the sociology of public action theoretical framework. Results indicate that the formation of a coalition of social movements has played a major role in the adoption of the national policy for agro-ecology and organic production. The design and implementation of this policy are based on a series of participatory and intersectoral mechanisms. The change of government in 2016 has blocked this process, but other dynamics can be anticipated at the local level.Keywords: Public policies; social movements; agro-ecology; organic agriculture; Brazil; L’objectif de la communication est double. Elle vise d’abord à examiner le processus historique qui a permis de placer l’agroécologie dans l’agenda des politiques publiques. En second lieu, il s’agit d’analyser les controverses, débats et luttes entre les différents acteurs porteurs d’un projet visant à définir et institutionnaliser un modèle agricole alternatif au modèle agricole dominant issu de la révolution verte.Cet objectif s’inscrit dans un débat particulièrement marqué au Brésil depuis une vingtaine d’année autour des aspirations de changements de trajectoire des politiques agricoles (Petersen, 2013). En effet, malgré la capacité innovatrice du pays à mettre en oeuvre des politiques de développement rural qui tentent de faire émerger un modèle agricole alternatif, le modèle de l’agrobusiness est resté largement dominant. Dans ce contexte, l’institutionnalisation apparente de l’agroécologie est-elle porteuse d’un changement de trajectoire des politiques publiques de développement rural au Brésil ? La communication se divise en quatre parties. La première présente brièvement le cadre théorico-méthodologique mobilisé, fondé sur des approches de sociologie de l’action publique. La seconde présente le contexte économique, politique et institutionnel qui caractérise la dualité des modèles agricoles au Brésil, et dans lequel l’agroécologie s’est progressivement insérée. La troisième examine le jeu d’acteurs qui a conduit à placer l’agroécologie au coeur du débat public, puis dans l’agenda politique. La quatrième section est consacrée à la construction des politiques publiques visant à renforcer l’émergence d'un ensemble d'instruments d'action gouvernementale pouvant être mobilisés en faveur de l'agroécologie. Enfin, la conclusion fait le point sur l’état de la mise en oeuvre de ces instruments.

Using Acrobeloides sp. (Cephalobidae) and Oryza sativa (Poaceae), we aimed at (i) studying the effects of bacterivorous nematodes on plant functions growing in a nutrient-poor soil in Madagascar, (ii) testing the mechanisms involved in the mutualistic activity of the bacterivorous nematodes in a strong P-depleted Ferralsol from the highlands of Madagascar, and (iii) identifying the agronomic and edaphic factors that can drive the soil microbial loop.Two pathways have been proposed to explain the positive effects of bacterial-feeders on nutrients availability and plant functions: mineralization pathway and exploration pathway. In order to test the involvement of each pathway in the mutualistic activity of bacterivorous nematodes, we assessed the effect of nematodes inoculation on inorganic P flows from soil to plant using the 32P labelling technique. When the soil pH was corrected with dolomite lime, we showed that the presence of Acrobeloides sp. improved net P mineralization and plant (Oryza sativa) functions (growth and nutrition) but did not alter lateral root growth as protists do. Indeed, in the presence of nematodes and dolomite, the shoot L-value increased by 49%, the plant total biomass increased by 22% and the plant total P amount increased by 9%. Thus, Acrobeloides sp. increased plant P uptake through the "nutritional" or "mineralization" pathway.The effects of Acrobeloides sp. on Oryza sativa functions were variable (positive, neutral or negative) according to agricultural practices and soil abiotic variables. First, these effects may depend on the rice cultivar used in the experiment. Indeed, the nematodes attractancy to root-adhering soils varied according to upland rice cultivar, probably according to the amount and composition of root exudates. The mutualistic activity of nematodes is also influenced (maximized) by the presence of trees (agroforestry) in the rice field. Besides plants, the abiotic soil parameters were key drivers. The mutualistic activity of nematodes was strongly limited by the ability of Ferralsols to precipitate and chemisorb phosphates. The addition of dolomite lime limited phosphates sorption on soil and enhanced the mutualistic activity of the nematodes. Also, the high values of soil pH and Mg content tended to increase the mutualistic activity of the bacterivorous nematodes on rice growth and nutrition. To conclude, we found that it is possible to drive the mutualistic activity of bacterivorous nematodes in poor tropical soils through specific soil and agricultural practices.; Les objectifs de cette thèse étaient (i) d'étudier les mécanismes par lesquels les nématodes bactérivores régulent les flux de nutriments (N et P) dans la rhizosphère du riz pluvial dans un sol ferrallitique de Madagascar, (ii) d'étudier les effets des interactions bactéries – bactérivores sur les fonctions de la plante (croissance et nutrition), et (iii) d'évaluer les principaux facteurs contrôlant la boucle microbienne des sols dans une optique d'intensification. Notre modèle biologique comprenait Acrobeloides sp. (Cephalobidae) et Oryza sativa (Poaceae).Deux voies ont été proposées pour expliquer les effets positifs des bactérivores sur la disponibilité des nutriments et les fonctions de la plante: voie de minéralisation et voie d'exploration. Afin d'identifier l'implication de chaque voie dans les flux de P inorganique à l'interface sol-plante nous avons utilisé le radio-isotope 32P comme traceur. Lorsque le pH du sol est corrigé par l'ajout de dolomie, la présence des nématodes bactérivores améliore la minéralisation nette de P, la production de biomasse et la nutrition de la plante sans modifier la ramification du système racinaire, contrairement à ce qui a été observé par certains auteurs en présence de protistes. En effet, en présence de nématodes et de dolomie, la L-value dans les parties aériennes de la plante augmente de 49%, la biomasse totale de la plante augmente de 22%, et la quantité de P total dans les tissus de la plante augmente de 9%. Ainsi, Acrobeloides sp. stimule le prélèvement de P par la plante via la voie nutritionnelle ou voie de minéralisation.Les effets de Acrobeloides sp. sur les fonctions de la plante sont variables (positives, neutres, négatives), en fonction des pratiques agricoles et des caractéristiques abiotiques du sol. Tout d'abord, ces effets peuvent dépendre de la variété de riz puisque l'attractivité des nématodes Acrobeloides sp. par la rhizosphère du riz varie en fonction des variétés de riz pluvial, plus précisément en fonction de la composition et de la quantité d'exsudats racinaires libérés par la plante. Ensuite, l'activité mutualiste des nématodes est influencée (maximisée) par la présence d'arbres (agroforesterie) dans la parcelle de riz pluvial. En plus des plantes, les paramètres édaphiques étaient des facteurs clés. L'activité mutualiste des nématodes est fortement limitée par le pouvoir fixateur des Ferralsols. Ainsi, l'ajout de dolomie limite la capacité de sorption de P du sol et améliore l'activité mutualiste des nématodes bactérivores. Enfin, l'activité mutualiste des nématodes sur la croissance et la nutrition du riz pluvial est favorisée par les valeurs élevées de pH et de teneur en Mg dans le sol. Pour conclure nous avons trouvé qu'il est possible d'intensifier l'activité mutualiste des nématodes bactérivores dans un sol tropical pauvre à travers des pratiques agricoles spécifiques (gestion des sols, agroforesterie).

Through the study of the Basque Country and Béarn, the relationship between a farmer project and an implementation of the short food supply chains, and their mutual development is studied. Indeed, there are a lot of short circuits, ranging from a commercial outlet for the farmer, the search for a "good and local" product for the consumer to the implementation of a farmer project. These short food supply chains respond to different logics, and therefore to different objectives. Some are more of a farmer's project initiators than others. Finally, the integration of this farmer project and short circuits within the relationship with para-agricultural organizations and public action is studied.; À travers l’étude du Pays basque et du Béarn, il est étudié la relation entre un projet paysan et la mise en place du circuit court, et sur leur développement mutuel. En effet, il existe une multitude de circuits courts, allant d’un débouché commercial pour l’agriculteur, la recherche d’un produit « bon et local » pour le consommateur, à la mise en place d’un projet paysan. Ces circuits courts répondent à des logiques différentes, et donc à des objectifs différents. Certains sont plus porteurs d’un projet paysan que d’autres. Finalement, il est étudié l’intégration de ce projet paysan et des circuits courts au sein de la relation avec des organismes para-agricoles et l’action publique.

International audience; Most of the C and N models published over past decades are based on parameters not always linked to the environment and underestimate the role of microorganisms. They are often over-parameterized, which can give multiple solutions for flow calculations between state variables. This work proposes a modelling method centred on the functioning of living organisms in order to calculate flow parameters using data on N stocks in decomposers, plant organs, symbiotic microorganisms, and the soil compartments. The model was settled via a complex N fixing and intercropping system of durum wheat/faba bean compared to the cropping of pure durum wheat and pure faba bean, all in the context of organic farming invaded by weeds and weeded by hand just before flowering. To avoid perturbation of natural exchanges of C and N, no fertilizer was added from 1997 to 2011. The equation system defined for the association of any number of plants, as well as parameters previously published for C-flow calculations were used, and only a few parameters specific to N flows were added, and are discussed. The results showed the strong link between N and C in the environment. The calculations converge toward an unique set of solutions that is consistent with literature data when available. The labile organic N of microbial origin was modelled as the main potentially available stock. Living microorganisms stored about 1% of total N, which was close to the N stock in faba bean and four times more than stock in durum wheat. Inorganic N was immobilized before flowering in competition with N requirement of durum wheat roots. Net N mineralization, mainly from decomposition of faba bean roots, started too late to improve wheat production. During the cropping period, weeds accounted for losses of 20 kg N ha−1, while the atmospheric N2 fixation of 90 kg N ha−1 was close to the total microbial immobilization. The model associating microbial and plant flows of C and N in complex plant covers, appears as a robust tool to quantify the exchanges of the earth organisms with the soil and atmosphere. It enables to propose essential recommendations to improve as well agro-ecology as predictions of global changes of C and N stocks.

International audience; AbstractSustainable agriculture and agro-ecology justify the need to study and understand the role played by ecological processes, and soil biodiversity in particular, in agro-ecosystem functioning. A large number of studies have focused on earthworms in temperate and humid tropical ecosystems and have demonstrated their importance for improving soil biological, physical, and chemical properties in agro-ecosystems. Their “success” is so essential that earthworms are widely considered key species and relevant indicators of soil health in temperate ecosystems. In arid and sub-arid ecosystems, the role of “soil engineer” is usually attributed to termites, and especially fungus-growing termites in Africa and Asia. However, despite this recognition, significant effort is spent eradicating them in plantations because of their pest status. In this review, we discuss the status of termites (“pests” vs. “soil engineers”) and question whether termites play similar roles to earthworms in arid- and sub-arid agroecosystems, with a focus on their influence on nutrient cycling and water dynamics. We argue that the dream of controlling natural interactions and ridding plantations of termites remains a costly legacy of the green revolution. We review the agricultural practices that have been used to reduce termite damage in plantations by restoring refuges to predators or by reorienting termite foraging activity towards organic amendments. Then, we show that the stimulation of termite activity can be used to improve key ecological functions in agro-ecosystems, such as increasing water availability to plants or producing fertility hot-spots. Finally, we suggest that more research on how termites can be used for improving ecosystem services, as is actually done with earthworms in temperate and humid tropical countries, could lead to a paradigm shift in our understanding of the impact of termites in tropical agro-ecosytems.

Ce numéro comprend les articles correspondant aux présentations du Colloque Casdar 2018.; National audience; Thrips are among the most important pests in greenhouses worldwide because of recurrent outbreaks of both native and invading species. Yet, their biodiversity, distribution and ecology remain still poorly documented, probably because of their small size, the high morphological similarity between taxa and their discretion apart from the outbreak in crops. In this study, we thus developed a so-called DNABarcoding approach coupling, on one side, the sequencing of some molecular markers - e.g. a part of the mitochondrial marker Cytochrome Oxidase I (COI) – and, on the other, the precise examination of some morphological characters. Thanks to a collaborative network, several thousands of samples were hence collected in or around crops and more than 1000 individuals were characterized, making it possible (i) to clarify the actual diversity of thrips in these agroecosystems, ii) to focus on some particular (risky and/or invading) species, iii) to design a fast, simple and low cost molecular diagnostic tool for their identification.; Les thrips comptent parmi les ravageurs les plus importants des agrosystèmes serres en raison des attaques récurrentes des espèces indigènes et envahissantes. Pourtant, la biodiversité, la distribution et l'écologie des différentes espèces de thrips sont encore peu documentées. Leur petite taille, la forte similitude morphologique entre les différentes espèces et leur discrétion en dehors des pullulations sur cultures expliquent probablement cette situation. Dans ce travail, nous nous sommes donc intéressés à la diversité des thysanoptères collectés en cultures ornementales en France via une approche de type « DNA-Barcoding » couplant une caractérisation moléculaire basée notamment sur une portion du gène mitochondrial cytochrome oxydase (COI) et une caractérisation précise sur des caractères morphologiques. Grâce à un vaste réseau collaboratif, plus de 1000 échantillons de thrips ont ainsi été échantillonnées parmi lesquels plusieurs centaines ont été caractérisés ce qui nous a permis i) de clarifier la diversité réelle des thrips dans ces agroécosystèmes, ii) de rechercher plus particulièrement certaines espèces spécifiques présentant des risques élevés et/ou nouvelles sur le territoire, iii) concevoir un outil de diagnostic moléculaire rapide, simple et peu coûteux pour leur identification en routine.

Ce numéro comprend les articles correspondant aux présentations du Colloque Casdar 2018.; National audience; Thrips are among the most important pests in greenhouses worldwide because of recurrent outbreaks of both native and invading species. Yet, their biodiversity, distribution and ecology remain still poorly documented, probably because of their small size, the high morphological similarity between taxa and their discretion apart from the outbreak in crops. In this study, we thus developed a so-called DNABarcoding approach coupling, on one side, the sequencing of some molecular markers - e.g. a part of the mitochondrial marker Cytochrome Oxidase I (COI) – and, on the other, the precise examination of some morphological characters. Thanks to a collaborative network, several thousands of samples were hence collected in or around crops and more than 1000 individuals were characterized, making it possible (i) to clarify the actual diversity of thrips in these agroecosystems, ii) to focus on some particular (risky and/or invading) species, iii) to design a fast, simple and low cost molecular diagnostic tool for their identification.; Les thrips comptent parmi les ravageurs les plus importants des agrosystèmes serres en raison des attaques récurrentes des espèces indigènes et envahissantes. Pourtant, la biodiversité, la distribution et l'écologie des différentes espèces de thrips sont encore peu documentées. Leur petite taille, la forte similitude morphologique entre les différentes espèces et leur discrétion en dehors des pullulations sur cultures expliquent probablement cette situation. Dans ce travail, nous nous sommes donc intéressés à la diversité des thysanoptères collectés en cultures ornementales en France via une approche de type « DNA-Barcoding » couplant une caractérisation moléculaire basée notamment sur une portion du gène mitochondrial cytochrome oxydase (COI) et une caractérisation précise sur des caractères morphologiques. Grâce à un vaste réseau collaboratif, plus de 1000 échantillons de thrips ont ainsi été échantillonnées parmi lesquels plusieurs centaines ont été caractérisés ce qui nous a permis i) de clarifier la diversité réelle des thrips dans ces agroécosystèmes, ii) de rechercher plus particulièrement certaines espèces spécifiques présentant des risques élevés et/ou nouvelles sur le territoire, iii) concevoir un outil de diagnostic moléculaire rapide, simple et peu coûteux pour leur identification en routine.

International audience; The observed decline in wild bees may be connected to the decreasing diversity of flowering plants. Changes in floral composition shape nutrient availability in inhabited areas, and bee larvae need food rich in body-building nutrients to develop into adults. Adult food, mainly composed of energy-rich nectar, differs from larval food, mainly composed of pollen, and adult bees forage on different plant species for nectar and pollen. Defining bee-friendly plants based on the quantities of food produced, and on the visitation rates of adult pollinating insects leads to the planting of bee habitats with poor-quality food for larvae, which limits their growth and development, and negatively affects the population. Consequently, failing to understand the nutritional needs of wild bees may lead to unintended negative effects of conservation efforts. Ecological stoichiometry was developed to elucidate the nutritional constraints of organisms and their colonies, populations, and communities. Here, I discuss how applying ecological stoichiometry to the study of the nutritional ecology of wild bees would help fill the gaps in our understanding of bee biology. I present questions that should be answered in future studies to improve our knowledge of the nutritional ecology of wild bees, which could result in better conservation strategies.

National audience; Sanitary requirements are strengthening in response to consumers’ expectations, European regulations and private actor’s requirements, through retailers, in particular. Farmers are directly concerned by the dynamic, which has emerged for the last twenty years, since specifically the “mad cow” crisis. Mayotte is a French overseas department since 2011 and an ultraperipherial region of Europe since 2014. It is supposed to comply to European requirements. However, numerous studies highlight that the retrofit between practices and sanitary expectations is not already achieved. In order to answer this inadequacy in a context where almost 80% of the total production is informal, we have surveyed 47 tomatoes producers. This production is very sensitive to pests and particularly to tomatoes fly during the dry season, which can destroy all or some parts of the harvest. We demonstrate that more than producers’ individual characteristics, numerous exogenous factor could help understand the inadequacy observed. Institutional environment could be a brake as well as a leverage to setting up more environmental friendly practices.

AGROSUPSPEEAGESTAD; In the present agroecological context, the reduction of herbicide uses becomes a substantial issue. For weed control and site specific weed management the development of new technologies is required to identify individual plant. Although many crop/weed discrimination methods have been developed, the automatic intra-row weed detection is still a challenge, particularly in wheat. An imaging system is developed to detect black grass in wheat at early growing stage. The technique mimics the method used by a human expert in such conditions. Thus, the hypocotyl diameter was used as distinguishing criterion. For experiments, the seeds of black grass and wheat were sown in rectangular pots. Two planting protocols were carried out to reproduce the emergence difference of species as observed in actual field conditions: 1) black grass and wheat were planted in the crop line at the same time; 2) black grass were planted in the crop line seven days after wheat. The imaging system consisted in a multispectral camera placed at 1.20 m above the pot soil surface. The view axis was tilted at 45° so that the side view of the crop row was captured in the image. Approximately 100 images were acquired at various times from plant emergence (BBCH-stage 11) to three leaf stage (BBCH-stage 13) of the wheat plant. The first step of image processing consisted in computing a color vegetation index (Excess Green Index) and thresholding the pixel values to provide a binary image of the plants without soil background. In the second step, various segmentation and filtering techniques were assessed to detect automatically the base of plant stems. Depending on the stem width, each plant was finally classified into wheat or black grass. Results are analyzed and discussed looking at the potential of this method regarding not only the plant species but also experimental conditions.

25 pages; International audience; Integrating principles of ecological intensification into weed management strategies requires an understanding of the many relationships among weeds, crops and other organisms of agro-ecosystems in a changing context. Extensively used during the last two decades in weed science, trait-based approaches have provided general insights into weed community response to agricultural practices, and recently to understanding the effect of weeds on agro-ecosystem functioning. In this review, we provide a holistic synthesis of the current knowledge on weed response and effect functional traits. Based on the literature and recent advances in weed science, we review current knowledge on (i) weed functional groups and ecological strategies, (ii) weed functional response traits to cropping systems and (iii) weed functional effect traits affecting agro-ecosystem functioning. For each functional trait, we explicitly present the assumptions and evidence on the linkage between trait values and ecological functions, in response to either management practices, for example tillage, sowing and herbicides, or biotic interactions, for example crop–weed competition and pollination. Finally, we address and discuss major research avenues that may significantly improve the use of traits and the knowledge of functional diversity in weed science for the future, especially to design and implement more environmentally sustainable weed management strategies.

AGROSUPSPEEAGESTADCT1DOCT; In an agroecological context (French Law on the Future of Agriculture), the reduction of herbicide uses become a crucial issue. It requires developing new technologies allowing a better knowledge of the field. The company AIRINOV, specialized in use of Unmanned Aerial Vehicle (UAV) dedicated to precision agriculture wants to explore a new approach by UAV to localize weed infestation areas. This work aims to develop a method analyzing images acquired by UAV to detect and map weeds in a field. The study is carried out on crops widely grown in France and requiring weed control at a young state of the plant : maize, sunflower and sugar beet. With its on-board sensors (GPS, multispectral camera…), the UAV can acquire georeferenced multispectral images of a whole field with a spatial resolution of 6 cm/pixel. The multispectral camera is also used to capture images at 6 mm/pixel on small field parts to assess the effect of image resolution. . A weed detection method is specifically developed to study multispectral image acquired by UAV. This method uses a spatial analysis based on the Hough Transform to localize crop rows. Weeds are then identified as the vegetation located in the inter-row space, and infestation maps are deduced from their GPS coordinates. Afterwards, these maps are finally transformed into herbicide application maps for site-specific weed management.

National audience; Many farms are now engaged in agro-ecological, more environmentally friendly trajectories. Conventional tools offered by accounting have some limits to measure farm competitiveness, performance and value. This assessment seems to call for both a broadening of the analytical framework and the production of a renewed accounting process. The article presents an overview of current issues encountered by a network of agricultural Champagne farms in the management and identifies possible ways of improving this accounting model.; Muchas explotaciones agrícolas se comprometen hoy en día en tomar una dirección más respetuosa con el medio ambiente. Las herramientas contables tradicionales son limitadas para poder medir la competitividad, rendimiento y patrimonio de las explotaciones. Estas medidas parecen necesitar a la vez de la ampliación del marco de análisis y de la renovación del proceso contable. Este artículo presenta una descripción de las problemáticas encontradas por una red de granjas agrícolas situadas en Champagne en la gestión de sus explotaciones e identifica posibles vías de mejora del modelo contable.; Bon nombre d’exploitations agricoles s’engagent aujourd’hui dans des trajectoires agro-écologiques plus respectueuses de l’environnement. Les outils classiques proposés par la comptabilité sont limités pour mesurer leur compétitivité, leur performance et évaluer leur patrimoine. Cette mesure semble appeler à la fois un élargissement du cadre d’analyse et la production d’un processus comptable renouvelé. L’article présente un état des lieux des problématiques actuelles rencontrées par un réseau de fermes en Champagne agricole dans la gestion de leurs exploitations et identifie des pistes d’améliorations possibles de ce modèle comptable.

[Departement_IRSTEA]Ecotechnologies [TR1_IRSTEA]MOTIVE; International audience; Agriculture must be both sustainable and economically viable. Sustainable agriculture requires new knowledge and expertise. However, knowledge management is not sufficient in current sustainable agriculture. To overcome this, we have made the assumption that the knowledge management practices used in industry can be transferred in agriculture. In this paper, we propose to apply to agriculture, the methodological tools developed by the French knowledge management group. These tools are based on theoretical approaches for the transformation of explicit and tacit knowledge within an organization. These tools are generic and suitable for any knowledge. We have tested the tool CFK for knowledge criticality in order to identify the knowledge to make explicit within a farm. This knowledge is critical because they are valuable, rare, complex and difficult to formalize. They must therefore be managed. We have determined the criticality of knowledge in a farm for organic agriculture field crops, in prairies and on various flora grain legumes. In the French research project TATABOX related to the agro-ecological transition study in a land between Tarn and Aveyron in France, we also have experimented another methodological tool (TRACO) for characterizing the most appropriate knowledge transfer tools to use between an agricultural cooperative and farmers. Among 16 knowledge transfer methods proposed, TRACO allow highlighting supervised self-education but also traditional teaching courses, communities of practices and workshops. Our conclusion is that the proposed knowledge management tools seem relevant to manage knowledge in agriculture, but they still require training and adaptation to agricultural fields.

International audience; Agriculture must be both sustainable and economically viable. Sustainable agriculture requires new knowledge and expertise. However, knowledge management is not sufficient in current sustainable agriculture. To overcome this, we have made the assumption that the knowledge management practices used in industry can be transferred in agriculture. In this paper, we propose to apply to agriculture, the methodological tools developed by the French knowledge management group. These tools are based on theoretical approaches for the transformation of explicit and tacit knowledge within an organization. These tools are generic and suitable for any knowledge. We have tested the tool CFK for knowledge criticality in order to identify the knowledge to make explicit within a farm. This knowledge is critical because they are valuable, rare, complex and difficult to formalize. They must therefore be managed. We have determined the criticality of knowledge in a farm for organic agriculture field crops, in prairies and on various flora grain legumes. In the French research project TATABOX related to the agro-ecological transition study in a land between Tarn and Aveyron in France, we also have experimented another methodological tool (TRACO) for characterizing the most appropriate knowledge transfer tools to use between an agricultural cooperative and farmers. Among 16 knowledge transfer methods proposed, TRACO allow highlighting supervised self-education but also traditional teaching courses, communities of practices and workshops. Our conclusion is that the proposed knowledge management tools seem relevant to manage knowledge in agriculture, but they still require training and adaptation to agricultural fields.

Tropical grasslands represent a pivotal arena for the sustainable intensification of agriculture in the coming decades. The abundant ecosystem services provided by the grasslands, coupled with the aversion to further forest destruction, makes sustainable intensification of tropical grasslands a high policy priority. In this article, we provide an inventory of agricultural initiatives that would contribute to the sustainable intensification of the tropical grassland agro-ecosystem, and we recommend a shift in the scientific priorities of animal scientists that would contribute to realization of a more agro-ecological and multi-functional agriculture in the world’s tropical grasslands.

Aphids are commonly considered major agricultural pests because of their ability to severely alter host plant physiology. However, their effects on fruit tree yield have not received wide attention and few existing works considering plant-aphid interaction and its consequences have only been conducted over a single year. We modified an existing process based model for the peach tree Prunus persica − green aphid Myzus persicae pathosystem, explicitly considering interactions between the two species under the influence of cultural practices (i.e. winter pruning and nitrogen fertilization), in order to simulate multi-year dynamics. The new model indicates that fertilization affects plant growth more than aphid infestation and the consequences of aphid infestation over fruit yield only emerge when considering the entire tree life span (ca. 10 yr). In fact, in a given year, aphid infestation mainly impairs shoot growth and, as fruits are borne on 1-yr old wood, its effects on fruit production are delayed in time. Our results are in accordance with the few existing experimental studies and highlight the need of considering multi-year dynamics, both via modelling and field observations, when dealing with perennial crops as fruit trees.

International audience; Agri-environment schemes (AESs) were implemented to reduce the loss of biodiversity in agro-ecosystems. This study aimed to assess whether AESs at either local or landscape scale increase the carabid abundance-activity and species richness. Carabids were sampled in 496 fields in a 430 km2 study area of central-western France. Based on the extensiveness of the agricultural practices involved, the different AES types were aggregated into three categories (AESEXT+, AESEXT++ and AESEXT+++) forming a gradient of extensiveness in farming practices. We sampled 20 fields in each of the three AESs categories. Each AES fields was paired with conventional fields. A series of statistical models were built to test the balance between the effects of AESs on either the carabid abundance-activity or species richness. AESs affected carabid abundance-activity and species richness both locally and at landscape scale (local characteristics having a greater effect than landscape composition). Carabid diversity benefited from AESs only when the most extensive practices were implemented, i.e. organic farming in cereal crops and delayed cutting in alfalfa. In addition, the local effects of organic farming and delayed cutting coverage interacted positively with these AESs at landscape scale. These results demonstrate that non-targeted organisms can benefit from AES management. They further emphasize the need to consider both local and landscape conditions when studying the effects of AESs on biodiversity. As only the most extensive practices had significant effects at both local and landscape scales, management must be planned strategically in space to ensure that AESs are distributed within the landscape to amplify their positive effects.

Agricultural changes have caused severe decline in the common bird communities in Europe. Mitigating this loss requires both understanding of and way to predict how agriculture affects biodiversity. The objective of this paper is to test the different dynamic models coupling bird abundances with farming land use. The agro-ecological calibration relies on 2002-2009 data for 34 bird species and 14 agricultural systems in 620 small agricultural regions of metropolitan France. The models are compared based on indicators of goodness-of-fit and predictive quality. The results highlight the relevance of systemic, functional, and mechanistic relationships between the agriculture and bird populations in both descriptive and predictive contexts. However, it seems that the best dynamic models to describe the past trends are not necessarily the most relevant to predict the future trends although there is a similar subset of five models that emerges in both cases. Ranking these different models depends on both the objective (describing or predicting) and the chosen functional level for the analysis (total community, functional groups or species).

In this study, we used LCA to test the influence of practicing low-input farming, on-farm processing and direct distribution on the environmental impact of bread consumption. Primary data were collected from four commercially active producers (two in France, one in Italy and one in Portugal) who cultivate cereals under low levels of inputs, process grains on farm and distribute their products directly to end consumers. Environmental impacts of products were compared to equivalents from supermarkets, characterised by higher rates of applied inputs at the agricultural stage, industrial processing and centralised distribution. The scope of LCA was from cradle to the consumer. The study revealed a high variability of results between individual cases. At the agricultural stage, products from a low-input cropping system integrated with livestock production in France and from a small-scale labour intensive production in Portugal showed similar or better performance on most impact categories to those from high-input agriculture, while horse farming in France and a stockless cultivation of ancient wheat cultivars in Italy revealed mostly higher environmental burdens. Decentralised processing and distribution in France had similar or slightly higher impacts to conventional supply chains, while Italian and Portuguese cases revealed clearly higher environmental burdens for most impact categories. Results demonstrate that while there might be a positive relationship between the scale and eco-efficiency of processing and distribution, the level of agricultural inputs, yields and transport distances cannot be used as proxies of environmental performance. Products of low-input systems can have much higher, similar or lower impacts to their high-input counterparts due to the influence of site conditions and the management. More research assessing the effectiveness of context-specific management systems is needed as oppose to the generic comparisons between labelling schemes (i.e. organic and conventional farming). (C) 2014 Elsevier Ltd. All rights reserved.

International audience; AbstractAgricultural intensification has led to the decrease of the diversity of wild and domestic pollinators. For instance, honeybees declined by 59 % in 61 years in the USA. About 35 % of major crops in the world depend on pollination services, and 3–8 % of world crop production will disappear without pollinators. Indeed, pollination provides several ecosystem services such as enabling crop and honey productions, regulating weeds and other cultural services. Agricultural intensification has also decreased weed diversity by about 50 % in 70 years because massive herbicide sprays have reduced the competition between weeds and crops. Nevertheless, weeds are at the basis of agricultural foodwebs, providing food to many living organisms. In particular, weeds provide flowers for pollinating insects including honey and wild bees. Here, we review the decline of weeds and bees. We discuss the effect of bees and pollination on crop production. We describe the complex interactions between bee pollinators, e.g. honey and wild bees, and landscape habitats such as crop fields and semi-natural elements. For that, we focus on spatial and temporal effects on flower resources. We show that weed abundance can reduce crop yields, thus inducing conflict with farmers. But weed abundance enhances regulating services by ensuring the survival of honeybees in the absence of oil seed crops. Weed abundance also enhances pollination services and, in turn, honey yield for the benefit of beekeepers. Weed abundance has also improved the survival of wild flora and the socio-cultural value of landscapes, a major request from the public. From those findings, we present a conceptual framework allowing to define ecological engineering options based upon ecosystem services of weeds and pollinators.

AimsThis study evaluated a framework for modelling the continuous exchange of carbon (C) between the atmosphere, plants, humus, and microorganisms, proposing a plant C model coupled to MOMOS, an existing microbial C model.MethodsC data were collected on low fertility cereal-legume cropping systems. Plant C and microbial C were modelled simultaneously and the growth parameters of plants and nitrogen-fixing microorganisms were fitted to the data.ResultsAll C exchanges were successfully predicted using the same weather correction for plant and microbial processes. Most of the photosynthetic production was allocated to the roots, reducing yields. The C losses were found modelled mainly by root respiration for cereals, probably as an energy source for nutrient explorings, and by root mortality for legumes as a growth source for decomposers and symbiotic nodules. The effect of root-nodule activity on shoot growth was found non-linear. The system was modelled as a sink of 4.2 Mg C ha-1 year−1 in the soil’s labile C reserve.ConclusionsThis paper coordinates theoretical bases for modelling the processes regulating plant productivity associated with plant C losses. The tool appears to be robust and is now available for calculating the essential parameters of agro-ecology and climate change.

This paper is about the research methods, stages, challenges and results of the LASCAUX programme, a European research programme that took place over five years, between February 2009 and January 2014. The LASCAUX programme is concerned with food issues, “from plough to plate”, from a mainly legal perspective. More particularly, the nuclear core of the programme is based on the study of the concept of "food security", according to the definition from the FAO. Studying food security is demanding for researchers in Law: being at the meeting point of different areas of law, but with no clear and indisputable way to identify a special field of the law that could be named food security law, its recognition and effectiveness depend on bringing together a vast set of coordinated rules which must be revealed or thought up. Besides, studying food security means working on legal issues which are not just technical but societal, with regard to socio-economic issues, and therefore concrete reality.

National audience; Haiti’s agriculture faces two main challenges: improving its contribution to food security—notably by generating income to combat poverty—and furthering the country’s sustainable development. It is also subject to frequent cataclysmic events (earthquakes, hurricanes, etc.). This paper investigates the capacity of agro-forestry systems to intensify food production and supply urban markets. It tests two complementary hypotheses, using surveys of experts and a cross-section of producers in the Port-au-Prince supply basins of Salagnac, Jacmel and Kensckoff. The first hypothesis posits that the emergence of commercial food farming depends on complementarities between different cropping systems, including agroforestry gardens. This type of agriculture, however, is characterized by a fragmented and diversified food supply structure, which presents limitations for the supply of urban markets. The second hypothesis relates to the producers’ capacity for collective action to lift these constraints by means of organizational innovations that generate added value and attract investments along the path to agro-ecological innovation. The verification of these hypotheses produces knowledge that can be leveraged in the design of food policies and research strategies to contribute to sustainable food security in Haiti.; L’agriculture haïtienne est soumise à deux défis principaux, celui d’améliorer sa contribution à la sécurité alimentaire notamment en générant des revenus pour lutter contre la pauvreté et celui de contribuer à l’aménagement durable du territoire. Elle est par ailleurs soumise à des événements accidentels fréquents (séismes, cyclones). Cet article interroge les capacités des systèmes agro-forestiers à intensifier la production alimentaire pour l’approvisionnement des marchés urbains. Il teste deux hypothèses complémentaires par des enquêtes à dires d’experts et auprès d’un échantillon de producteurs dans les bassins d’approvisionnement de Port-au-Prince de Salagnac, Jacmel et Kensckoff. La première hypothèse suppose que l’émergence d’une agriculture vivrière marchande repose sur les complémentarités entre différents systèmes de culture dont les jardins agroforestiers. Elle se traduit cependant par une structure atomisée et diversifiée de l’offre alimentaire qui présente des contraintes pour l’approvisionnement des marchés urbains. La deuxième hypothèse porte sur la capacité d’action collective des producteurs à lever ces contraintes par des innovations organisationnelles qui génèrent des gains de valeur et des investissements sur une trajectoire d’innovation agro-écologique. La vérification de ces hypothèses produit des connaissances mobilisables dans l’élaboration des politiques alimentaires et de recherche pour contribuer à une sécurité alimentaire durable en Haïti.

This paper offers a historical perspective on the interactions between legal standards and agricultural practices relating to guaraná, an energy-inducing Amazonian plant that is in increasing demand. Guaraná is managed in a number of socio-technical contexts, ranging from the fizzy drink industry to alternative agro-ecological farming systems, and is subject to a great many legal rules that determine the conditions for its use and appropriation. The paper shows how, in guaraná's native region of Maués, Brazilian Amazonia, various stakeholders including the indigenous population, associations of smallholdings and multinationals use legal standards in order to gain prerogatives over the plant and/or win a share of a growing market. In spite of the fact that the plant has been domesticated by the Sateré-Mawé and that traditional knowledge has been recognized in Brazil, to a certain extent history has dispossessed them of their rights to guaraná. New political and economic circumstances have favoured those actors committed to strategies of agricultural modernization and industrial processing. On the other hand, the ecologization of agriculture and the increasing numbers of instruments for differentiating production (such as fair trade, organic farming and geographical indications) seem to be favouring diversification in the methods of managing guaraná, as well as a certain re-appropriation of the plant by local communities.

Master

This paper questions the Lewis Path perspective of a "world without agriculture" which underpins the "structural transformation" paradigm of "modern growth." It shows that the Lewis Path is only one of four potential structural paths, and that half of the world's population is spiralling into a "Lewis Trap" with more farmers and an increasing income gap between them and other workers. After showing how land constraints and the productivity dynamics outside agriculture might prevent this population from switching to a Lewis Path, it delineates the condition of an alternative path that would not transfer the disparity problem to cities., Cet article interroge le paradigme de " transformation structurelle " et de " croissance moderne " qui conduit in fine à un " monde sans agriculture ". Il montre d'abord que ce " chemin de Lewis " (Lewis Path) n'est qu'une voie parmi quatre possibles, et que seuls les pays industrialisés ou en transition l'ont suivi durant les dernières décennies. La moitié de la population mondiale est plutôt embarquée dans une direction diamétralement opposée (Lewis Trap) où la population active agricole croît ainsi que son écart de revenu avec les autres travailleurs. En recomposant les productivités partielles de la terre et du travail en calories de 1961 à 2007, l'article montre ensuite comment la contrainte en terre interdit à la plupart des actifs agricoles d'augmenter la productivité de leur travail par la moto-mécanisation à grande échelle. Enfin, des simulations numériques projetant l'Inde en 2050 montrent quels facteurs extérieurs à l'agriculture barrent la route de Lewis à ce pays et d'autres. L'article introduit et discute alors un autre paradigme de développement, celui d'une intensification écologique hautement productive à petite échelle, intensive en travail comme en savoirs génériques et locaux, insérée dans le secteur manufacturier comme dans celui des services.

International audience; Our exploratory work refers to the socio-ecological transition and the ecologically desirable economic de-growth. We introduce the concept of "slow management" as a set of management alternatives to the dominant managerial approaches. The study of a sustainable farming organization in agro-ecology allows us to build an accounting model that could be inspiring for all fields of activity. Our model can be considered as an ideal-type for slow management practices, with four pillars to support it: slowness, respect for human beings, ecology and smallness.

This paper questions the Lewis Path perspective of a "world without agriculture" which underpins the "structural transformation" paradigm of "modern growth." It shows that the Lewis Path is only one of four potential structural paths, and that half of the world's population is spiralling into a "Lewis Trap" with more farmers and an increasing income gap between them and other workers. After showing how land constraints and the productivity dynamics outside agriculture might prevent this population from switching to a Lewis Path, it delineates the condition of an alternative path that would not transfer the disparity problem to cities.

Etendue géographique : Allemagne

Soumis à la conférence INFORSID; The work concerned the assembly of biological sub-systems to gain access to a functional representation of the overall system, in the case of complex biological interactions (symbiosis, etc.). The proposed method uses the statement of expert knowledge described in a literal way to establish the sub-system interface program. The use of interrogative pronouns and adverbs provides a formal framework to produce graphs from literal descriptions. In terms of results, the method enables (i) access to the vocabulary of the assembly program, (ii) identification of the transformation functions to be established, and (iii) an estimation of the valence required by programs to ensure assembly. From an operational perspective, the generic approach proposed is a theoretical construct that remains to be validated in concrete cases of application.

Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699; International audience; The ex ante assessment of innovative agro-ecological innovations is a key step in the development of more sustainable crop management systems. To this end, models are useful tools because they make it possible to rapidly assess numerous innovations in different contexts. Whereas many farm optimisation models focusing on the farmer’s strategic decision to adopt new crop management systems have been published, little attention has been given to the ex ante modelling of the dynamic operational impacts of innovation adoption at the farm level. BANAD, a mechanistic model for such applications,is proposed. It allows the ex ante assessment of innovative management systems including new agroecological techniques, while taking into account different farming contexts and policy and market conditions. It includes three components: (i) a crop management system model, (ii) a crop model (SIMBA) and (iii) a farming system model. Our results applied to the ex ante assessment of six innovative banana management systems for three contrasted farm types in Guadeloupe showed that the impacts of agroecological innovations, which include rotations, improved fallow, intercropping, pest-resistant cultivar, and an integrated organic system, can vary considerably according to (i) the farm type in which the innovation is integrated, (ii) the nature of the agro-ecological innovations, and (iii) the criteria considered and the temporal horizon of the assessment. Innovative intercropping systems that were effective at the field level in terms of the yield improvement and decreased pesticide use could be problematic at the farm level because they increased the workload and decreased income. The adoption of rotations or improved fallow seemed to be relevant for smallholders but could induce a critical period of 1.5–2.5 years during which income decreased drastically. Under certain conditions of markets and subsidies, very environmentally friendly innovations that are less productive can however be economically effective.

Agricultural production is evolving towards systems able to provide multiple objectives in order tosatisfy the complex concerns related to sustainability, therefore leading agricultural research to bear growing interest in the development of methodologies to allow the design and assessment of innovative cropping and farming systems able to fulfil these constraints. Although the number and the diversity of tools and concepts are increasing, only few transdisciplinary research have been done, therefore limiting the development of methodologies for integrated assessment from the design to the adoption of innovations by farmers. The objective of this thesis is to propose a trandisciplinary method for ex ante assessment of innovative cropping systems in order to palliate this shortcoming in the current research. After a survey of available assessment methodologies, we propose an original method which is made of a four-step approach: i) modelling farm diversity and prototyping innovative cropping systems, ii) use of a crop model to simulate the biophysical impacts of innovations for the different farm types, iii) development of a bio-economic farm model for assessment of the impacts of the adoption of innovations at farm level, and iv) econometric modelling of adoption by farmers. The method was then applied to the design and assessment of innovative cropping systems for banana production in the French West Indies, that are currently facing severe economic and environmental crisis. The first step led to the identification of six contrasting farm types and sixteen cropping systems prototypes, invoving rotation of banana with cover crop, intercropping, and regulation of pesticide use. The second step showed that the performances of innovation may differ greatly among fram types, and some systems appear to be promising from both agronomic and environmental critera. However simulations made in step 3 and 4 showed that promising innovations at field level maight have negative impacts at farm level while some promising innovation have low probability of adoption. Results of econometric model and bio-economic simulations made possible to define a set of proposals for local research and development stakeholders in order to improve the likelihood of adoption of the innovations. In the last chapter we present a critical analysis of the advantages and shortcomings of our approach underling the genericity of the methodology, and the potential extension of its application to other context, for better matching the innovations with society and farmers demands; Face à la multiplication et la complexité croissante des objectifs assignées à l'agriculture, les méthodologies de conception et d'évaluation ex ante de systèmes de culture innovants font l'objet d'un effort de recherche très soutenu. Cependant malgré le foisonnement de recherches et de productions d'outils disciplinaires, peu de recherches d'interface ont été entreprises, ce qui limite les possibilités d'évaluations ex ante globales des systèmes innovants, de la conception à l'adoption par les agriculteurs. L'objectif de cette thèse est de contribuer à l'avancée de ces travaux, en proposant une méthode transdisciplinaire d'évaluation ex ante de systèmes de culture innovants basée sur la combinaison d'outils de modélisation issus de l'agronomie et de l'économie. A partir d'une analyse de la littérature actuelle et de ses forces et faiblesses, nous construisons une méthode originale qui se décompose en 4 étapes : i) modélisation de la diversité des exploitations et prototypage de systèmes innovants plus durables, ii) utilisation d'un modèle de culture pour simuler le fonctionnement biophysique des innovations dans les types d'exploitations, iii) évaluation des impacts de l'adoption sur le fonctionnement et les performances des types d'exploitation à l'aide d'un modèle bioéconomique d'exploitation, iv) modélisation ex ante de l'adoption par les planteurs à l'aide d'un modèle économétrique. La méthode est ensuite appliquée à la conception et à l'évaluation ex ante de prototypes de systèmes de cultures bananiers aux Antilles françaises, qui traversent actuellement une crise socio-économique et environnementale sévère. L'application de la première étape de la méthode a permis d'identifier 6 types d'exploitations très contrastés avec des problèmes de durabilité se déclinant différemment et de mettre au point 16 prototypes de systèmes innovants impliquant plante de couverture cultivées en association ou en rotation, nouvelles variétés de bananiers, et réduction de l'usage des intrants chimiques. La deuxième étape a montré que les performances agronomiques des prototypes peuvent varier considérablement d'un type d'exploitation à un autre, et que certains systèmes semblent très prometteurs sur le plan agronomique et environnemental. Cependant les modélisations réalisées en étape 3 et 4 montrent que d'une part, des innovations performantes à la parcelle peuvent poser des problèmes de trésorerie et de charge de travail à l'échelle de l'exploitation, et que d'autre part certaines innovations très prometteuses ont pourtant un taux d'adoption faible. Les résultats du modèle économétrique et des simulations réalisées en étapes 2 et 3 permettent alors de définir un ensemble de propositions d'action à destinations des acteurs de l'innovation et du développement en vue de maximiser les chances d'adoption de systèmes plus durables. Le dernier chapitre de cette thèse revient sur les forces et les faiblesses de la méthode et souligne sa généricité potentielle qui devrait donc permettre d'étendre son application à d'autres contextes afin d'assurer une meilleure adéquation entre les innovations produites par la recherche agronomique et les attentes des agriculteurs et de la société.

Face à la multiplication et la complexité croissante des objectifs assignés à l’agriculture, les méthodologies de conception et d’évaluation ex ante de systèmes de culture innovants font l’objet d’un effort de recherche très soutenu. Cependant malgré le foisonnement de recherches et de productions d’outils disciplinaires, peu de recherches d’interface ont été entreprises, ce qui limite les possibilités d’évaluations ex ante globales des systèmes innovants, de la conception à l’adoption par les agriculteurs. L’objectif de cette thèse est de contribuer à l’avancée de ces travaux, en proposant une méthode transdisciplinaire d’évaluation ex ante de systèmes de culture innovants basée sur la combinaison d’outils de modélisation issus de l’agronomie et de l’économie. A partir d’une analyse de la littérature actuelle et de ses forces et faiblesses, nous construisons une méthode originale qui se décompose en 4 étapes : i) modélisation de la diversité des exploitations et prototypage de systèmes innovants plus durables, ii) utilisation d’un modèle de culture pour simuler le fonctionnement biophysique des innovations dans les types d’exploitations, iii) évaluation des impacts de l’adoption sur le fonctionnement et les performances des types d’exploitation à l’aide d’un modèle bio-économique d’exploitation, iv) modélisation ex ante de l’adoption par les planteurs à l’aide d’un modèle économétrique. La méthode est ensuite appliquée à la conception et à l’évaluation ex ante de prototypes de systèmes de cultures bananiers aux Antilles françaises, qui traversent actuellement une crise socio-économique et environnementale sévère. L’application de la première étape de la méthode a permis d’identifier 6 types d’exploitations très contrastés avec des problèmes de durabilité se déclinant différemment et de mettre au point 16 prototypes de systèmes innovants impliquant plante de couverture cultivées en association ou en rotation, nouvelles variétés de bananiers, et réduction de l’usage des intrants chimiques. La deuxième étape a montré que les performances agronomiques des prototypes peuvent varier considérablement d’un type d’exploitation à un autre, et que certains systèmes semblent très prometteurs sur le plan agronomique et environnemental. Cependant les modélisations réalisées en étape 3 et 4 montrent que d’une part, des innovations performantes à la parcelle peuvent poser des problèmes de trésorerie et de charge de travail à l’échelle de l’exploitation, et que d’autre part certaines innovations très prometteuses ont pourtant un taux d’adoption faible. Les résultats du modèle économétrique et des simulations réalisées en étapes 2 et 3 permettent alors de définir un ensemble de propositions d’action à destinations des acteurs de l’innovation et du développement en vue de maximiser les chances d’adoption de systèmes plus durables. Le dernier chapitre de cette thèse revient sur les forces et les faiblesses de la méthode et souligne sa généricité potentielle qui devrait donc permettre d’étendre son application à d’autres contextes afin d’assurer une meilleure adéquation entre les innovations produites par la recherche agronomique et les attentes des agriculteurs et de la société., Agricultural production is evolving towards systems able to provide multiple objectives in order to satisfy the complex concerns related to sustainability, therefore leading agricultural research to bear growing interest in the development of methodologies to allow the design and assessment of innovative cropping and farming systems able to fulfil these constraints. Although the number and the diversity of tools and concepts are increasing, only few transdisciplinary research have been done, therefore limiting the development of methodologies for integrated assessment from the design to the adoption of innovations by farmers. The objective of this thesis is to propose a trandisciplinary method for ex ante assessment of innovative cropping systems in order to palliate this shortcoming in the current research. After a survey of available assessment methodologies, we propose an original method which is made of a four-step approach: i) modelling farm diversity and prototyping innovative cropping systems, ii) use of a crop model to simulate the biophysical impacts of innovations for the different farm types, iii) development of a bio-economic farm model for assessment of the impacts of the adoption of innovations at farm level, and iv) econometric modelling of adoption by farmers. The method was then applied to the design and assessment of innovative cropping systems for banana production in the French West Indies, that are currently facing severe economic and environmental crisis. The first step led to the identification of six contrasting farm types and sixteen cropping systems prototypes, invoving rotation of banana with cover crop, intercropping, and regulation of pesticide use. The second step showed that the performances of innovation may differ greatly among fram types, and some systems appear to be promising from both agronomic and environmental critera. However simulations made in step 3 and 4 showed that promising innovations at field level maight have negative impacts at farm level while some promising innovation have low probability of adoption. Results of econometric model and bio-economic simulations made possible to define a set of proposals for local research and development stakeholders in order to improve the likelyhood of adoption of the innovations. In the last chapter we present a critical analysis of the advantages and shortcomings of our approach underling the genericity of the methodology, and the potential extension of its application to other context, for better matching the innovations with society and farmers demands.

International audience; Post-dispersal seed predation is an important source of mortality in plant populations. If this phenomenon is better known in tropical and woody systems, information is lacking for weeds in French agrosystems. In this paper, we evaluated seed predation variability in an organic wheat field by conducting experiments on weed seed preference and on spatial and temporal variation in predation rates. Weed seed predation preferences followed a species rank: Viola arvensis = Stellaria media > Alopecurus myosuroides = Chenopodium album > Sinapis arvensis = Anagallis arvensis = Galium aparine > > Plastic globules (for control), with weekly mean predation rates between 19 and 84%. The experiment on spatial variation in seed predation did not reveal a field border edge effect on predation rate with S. arvensis. However, a strong temporal variability has been found within a single season. Simple seeds characteristics as well as meteorological conditions were not directly correlated to predation rates obtained. High predation rates observed here underline the potential importance of this phenomenon on weed population dynamics. A future challenge would be to quantify the impact of post-dispersal seed predation on weed communities in order to assess the potential of seed predation for biological weed management.

National audience; Population growth in Brazil’s Nordeste is exerting increasing pressure on the natural vegetation, with concomitant losses in fauna and flora diversity, accelerating erosion, deteriorating soil fertility and underground water quality and advancing desertification. Population pressure on the natural vegetation is partly the result of the prevailing model of agricultural modernisation. Based on a study of management practices in the caatinga (dense tree-covered steppe dominated by deciduous thorny vegetation)among a network of farmers, we are investigating agro-ecological possibilities for intensifying the production systems suggested by research and based on making better use of the various tree functions. Weconclude with an analysis of trends inBrazilian research.; El incremento demográfico en el nordestebrasileño conlleva una presióncreciente sobre la vegetación naturaly va acompañado de una pérdida dela diversidad faunística y florística, dela aceleración de los procesos de erosión,de la disminución de la fertilidadde los suelos y de la calidad delas aguas subterráneas, así como dela progresión de la desertificación.Esta presión sobre la vegetación naturalfue, en parte, favorecida por elmodelo dominante de modernizaciónde la agricultura. A partir del estudiode prácticas de manejo de la caatinga(estepa arbolada densa con predominiode especies espinosas caducifolias)por una red de agricultores, estudiamoscuáles son las posibilidadesagroecológicas de intensificación delos sistemas de producción propuestospor la investigación y que sebasan en un mejor aprovechamientode las funciones del árbol. Se concluye analizando las evoluciones de la investigación brasileña.; L’augmentation démographique dans le Nordeste brésilien entraîne une pression accrue sur la végétation naturelle et s’accompagne d’une perte de la diversité faunistique et floristique, de l’accélération des processus d’érosion, de la diminution de la fertilité des sols et de la qualité des eaux souterraines ainsi que de la progression de la désertification. Cette pression sur la végétation naturelle a été, en partie, favorisée par le modèle dominant de modernisation de l’agriculture. À partir de l’étude des pratiques de gestion de la caatinga (steppe arborée dense où dominent les épineux caducifoliés) d’un réseau d’agriculteurs, nous étudions quelles sont les possibilités agroécologiques d’intensification des systèmes de production proposées parla recherche et fondées sur une meilleure valorisation des fonctions de l’arbre. Nous terminons en analysant les évolutions de la recherché brésilienne.