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La diversification (allongement des rotations, introduction de cultures intermédiaires, cultures relais, associations…) est un des leviers majeurs pour une transition agroécologique des systèmes de culture. Cependant, toute diversification n’est pas bonne en soi car ses performances dépendent des cultures introduites et de la manière de les assembler. Pour aider les acteurs à orienter leur choix de configuration des systèmes de culture, nous avons développé un indicateur de diversité globale des cultures de la rotation (I-DGC) basé sur une construction en arbre hiérarchique. Celui-ci comprend une évaluation des diversités temporelle et spatiale. La diversité temporelle est ensuite décomposée en un indicateur de diversité taxonomique et un de diversité fonctionnelle, celle-ci étant liée à la fourniture de douze services écosystémiques (SE). L’indicateur global calculé à partir des données sur les cultures permet d’estimer a priori, l’effet potentiel de la diversification d’une rotation. L’estimation des douze SE sur un ensemble de rotations typiques des agroécosystèmes montre des variations importantes. Par ailleurs, l’allongement de la rotation et l’augmentation du nombre de cultures ne sont pas suffisants ; ils doivent être associés à un choix adéquat des cultures et de leur succession. Mots clés : transition agroécologique, diversification, diversité spatio-temporelle, succession cultures, association de culture, cultures en bandes

This flyer explains what crop diversification is. It outlines crop diversification strategies, some of the challenges associated with crop diversification and what DiverIMPACTS is doing to achieve crop diversification.&nbsp

International audience; Ce numéro d’Agronomie, environnement & sociétés rend compte des travaux de la 10èmeédition des Entretiens du Pradel (septembre 2019), qui se situait dans le contexte particulier de la commémoration nationale du quadricentenaire de la mort d’Olivier de Serres (1539-1619). Plutôt que traiter un seul sujet à enjeu d’avenir pour les agronomes, marque de fabrique des Entretiens du Pradel depuis 2000, l’Association française d’agronomie a choisi pour cette édition de commémorer à sa manière(en privilégiant les regards croisés entre pratique et théorie, et en cultivant l’interdisciplinarité)la mémoire d’Olivier de Serres, en faisant écho à son œuvre magistrale publiée en 1600: Théâtre d’agriculture et mesnage des champs. L’ouvrage, organisé en huit chapitres (appelés Lieux), propose au lecteur les savoirs de l’époque nécessaires à la production agricole, à la gestion d’une ferme, et àla vie familiale dans une ferme. Il constitue une véritable encyclopédie des savoirs dela pratique agricole de l’époque.Mais en 1600, le mot agronomie n’existant pas encore, et la discipline scientifique encore moins, la filiation des agronomes avec Olivier de Serres se fait avant tout par son approche des problèmes de production dans ses parcelles de culture, de gestion technique de sa ferme, et de sa relation au territoire, tant pour son usage sur l’exploitation (cas de la gestion de l’eau) que pour la diffusion de ses innovations. J.Caneill,agronome passionné d’histoire, ouvre ainsi ce numéropar un article au titre explicite: « L’œuvre d’Olivier de Serres: les prémices d’une agronomie qui n’a pas encore de nom».Et dans le prolongement de ce texte, P. Cornu, historien, et J-M.Meynard, agronome, réfléchissent à deux voix dans un texte «sur le sens que prend la convocation des héritages combinés des idées et des pratiques agronomiques dans un ‘’temps présent de toutes les urgences’’»

Synthetic Biology (SynBio) is an interdisciplinary field at the interface of engineering and biology aiming to develop new biological systems and impart new functions to living cells. EFSA has been asked by the European Commission to evaluate SynBio developments in agri-food with the aim of identifying the adequacy of existing guidelines for risk assessment and determine if updated guidance is needed. The scope of this opinion covers the molecular characterisation and environmental risk assessment of such genetically modified plants obtained through SynBio, meant to be for cultivation or food and feed purposes. The previous work on SynBio by the non-food scientific Committees (2014, 2015) was used and complemented with the output of a horizon scanning exercise, which was commissioned by the EFSA to identify the most realistic and forthcoming SynBio cases of relevance to this remit. The horizon scan did not identify other sectors/advances in addition to the six SynBio categories previously identified by the non-food scientific committees of the European Commission. The exercise did show that plant SynBio products reaching the market in the near future (next decade) are likely to apply SynBio approaches to their development using existing genetic modification and genome editing technologies. In addition, three hypothetical SynBio case studies were selected by the working group of the Panel on Genetically Modified Organisms (GMO), to further support the scoping exercise of this Scientific Opinion. Using the selected cases, the GMO Panel concludes that the requirements of the EU regulatory framework and existing EFSA guidelines are adequate for the risk assessment of SynBio products to be developed in the next 10 years, although specific requirements may not apply to all products. The GMO Panel acknowledges that as SynBio developments evolve, a need may exist to adjust the guidelines to ensure they are adequate and sufficient., European Commission: EFSA-Q-2018-01000.

International audience; Rural areas and farms in France have become more and more specialized, while there is evidence that crop diversification can largely contribute to reducing input use in agriculture (pesticides, fertilizer, irrigation) and related negative environmental impacts. This study analysed potential obstacles to crop diversification at various levels of the supply chains through two approaches:• Interviews with stakeholders, to conduct a cross-cutting analysis of impediments to the development of various diversification crops; • A detailed study of the value-chains and of their modes of coordination, focusing on three case studies: pea and linseed for animal feeding, hemp for insulation and biomaterials. A lock-in was identified around the dominant species, such as wheat, rapeseed, and maize, which are more and more profitable with increasing investments in genetics, agronomic references, markets... This situation has been favoring short rotations over time. This lock-in caused several inter-connected impediments hindering crop diversification, such as: • the lack of availability of crop varieties and methods of crop protection for minor crops, • the scarcity of data on performances of minor crops at the crop rotation level, • the complexity of the knowledge to be acquired by farmers, • logistical constraints to harvest minor crops, and • the lack of coordination within the emerging supply chains. The simultaneous and coordinated implementation of two major categories of levers was proposed to help actors incorporate greater crop diversity into their productive systems and foster agroecological transition: 1. Support the development of innovative niches and develop learning- for-innovation processes through e.g. long-term partnership between supply chain actors, research and development, advisory and decision-makers, labelling systems, investment in technological innovations for minor crops, management of crop diversification at landscape level; 2. Encourage the standard sociotechnical system to evolve and make it more disposed to crop diversification, through public policies, including the Common Agricultural Policy, regulation and promotion of diversified value chains via public contracts. All recommendations have to be considered simultaneously and on the long-term, as sectorial measures, which target only one component of the value-chain, have proven to fail. This study was a direct source of inspiration for the ongoing H2020 project DiverIMPACTS (Diversification through Rotation, Intercropping, Multiple Cropping, Promoted with Actors and Value Chains towards Sustainability, http://www.diverimpacts.net/), which uses the same theoretical framework, further extends the case studies to intercropping, multiple cropping and crop rotation strategies across Europe, goes beyond the identification of barriers to co-design practical solutions together with value chains’ actors and makes recommendations for institutional changes.

National audience; Ce numéro, consacré à l’irruption du numérique en agriculture, est issu d’une réflexion engagée lors de l’Assemblée générale de l’Afa de Mars 2017. Bien que ce numéro soit moins fourni en textes que les précédents, il conforte la revue dans ses choix de donner de la visibilité à la fois aux analyses distanciées, à des états des lieux, à des témoignages sur des pratiques et à des points de vue pouvant donner lieu à controverses : toutes ces formes d’appréhension de la réalité sont utiles lorsqu’il s’agit de traiter de thématiques émergentes comme celle de ce numéro. Il la conforte également dans son choix d’associer la réflexion sur l’évolution de l’agriculture à celle des outils et métiers d’agronomes. La révolution numérique en agriculture pose en effet un défi à tous les agronomes, que ceux-ci évoluent dans le milieu économique, dans le monde de la recherche ou du développement ou de l’action publique : l’évolution en cours des métiers, notamment celui de conseil, rend urgent une adaptation des formations, initiale et continue, préoccupation qui est traitée de diverses façons dans ce numéro. Mais la révolution numérique aura probablement des conséquences majeures sur la façon dont on fait de la recherche et la réflexion à ce sujet est balbutiante. L’absence de texte consacré à l’impact du numérique dans les pratiques des chercheurs en est sans doute un signe.

International audience; We developed a simulation model for quantifying the spatio-temporal distribution of contaminants (e.g., xenobiotics) and assessing the risk of exposed populations at the landscape level. The model is a spatio-temporal exposure-hazard model based on (i) tools of stochastic geometry (marked polygon and point processes) for structuring the landscape and describing the exposed individuals, (ii) a dispersal kernel describing the dissemination of contaminants from polygon sources, and (iii) an (eco)toxicological equation describing the toxicokinetics and dynamics of contaminants in affected individuals. The model was implemented in the briskaR package (biological risk assessment with R) of the R software. This article presents the model background, the use of the package in an illustrative example, namely, the effect of genetically modified maize pollen on nontarget Lepidoptera, and typical comparisons of landscape configurations that can be carried out with our model (different configurations lead to different mortality rates in the treated example). In real case studies, parameters and parametric functions encountered in the model will have to be precisely specified to obtain realistic measures of risk and impact and accurate comparisons of landscape configurations. Our modeling framework could be applied to study other risks related to agriculture, for instance, pathogen spread in crops or livestock, and could be adapted to cope with other hazards such as toxic emissions from industrial areas having health effects on surrounding populations. Moreover, the R package has the potential to help risk managers in running quantitative risk assessments and testing management strategies.

EASPEGESTADAGROSUPINRA; L'utilisation répétée du glyphosate, en interculture et/ou en culture (dans le cas de cultures tolérantes au glyphosate), peut conduire à la sélection de populations d’adventices résistantes à cet herbicide. Dans cette étude, nous avons introduit un module de génétique dans le modèle de dynamique adventice FLORSYS prédisant mutation, sélection et coûts de la résistance. Nous avons simulé des systèmes de culture à base de maïs, avec différentes fréquences d'application de glyphosate, rotations, intensités de travail du sol et dates de semis. Nous avons analysé la probabilité et le délai d'apparition de la résistance, ainsi que son impact sur la nuisibilité et les bénéfices de la flore adventice, en fonction (1) des systèmes de culture, (2) des techniques culturales individuelles, (3) des traits d'espèces adventices.

EU agriculture is currently in transition from conventional crop protection to integrated pest management (IPM). Because biocontrol is a key component of IPM, many European countries recently have intensified their national efforts on biocontrol research and innovation (R&I), although such initiatives are often fragmented. The operational outputs of national efforts would benefit from closer collaboration among stakeholders via transnationally coordinated approaches, as most economically important pests are similar across Europe. This paper proposes a common European framework on biocontrol R&I. It identifies generic R&I bottlenecks and needs as well as priorities for three crop types (arable, vegetable and perennial crops). The existing gap between the market offers of biocontrol solutions and the demand of growers, the lengthy and expensive registration process for biocontrol solutions and their varying effectiveness due to variable climatic conditions and site-specific factors across Europe are key obstacles hindering the development and adoption of biocontrol solutions in Europe. Considering arable, vegetable and perennial crops, a dozen common target pests are identified for each type of crop and ranked by order of importance at European level. Such a ranked list indicates numerous topics on which future joint transnational efforts would be justified.

This poster about the Horizon 2020 project DiverIMPACTS was presented at the Agri Innovation Summit in Lisbon in October 2017.

The European Food Safety Authority (EFSA) carried out a consultation to collect input from the scientific community and all interested parties for the risk assessment of the low level (LL) presence of genetically modified plant material in imported food and feed under Regulation (EC) No 1829/2003. A two-step approach was followed. The draft LL Scientific Opinion was prepared by the ad hoc Working Group of the EFSA Panel on Genetically Modified Organisms (GMO Panel) and endorsed by the Panel for a dedicated consultation with European Member States at its plenary meeting on 21 September 2016. EFSA received approximately 100 comments on the draft LL Scientific Opinion from 11 Member States. Based on the outcome of the dedicated consultation, a second draft LL Scientific Opinion was prepared and endorsed by the Panel for a dedicated consultation with European Member States at its plenary meeting on 5 April 2017. EFSA received approximately 60 comments on the draft LL Scientific Opinion from 7 interested parties. The current report summarises the outcome of the two-step consultation, and includes a brief description of the comments received and how the comments were addressed. Comments related to policy or risk management aspects were considered out of the remit of the GMO Panel and outside the scope of these consultations; therefore these are not addressed in this document. The GMO Panel prepared an updated version of the LL Scientific Opinion taking into account the comments under its remit received. EFSA and its GMO Panel wish to thank European Member States, all stakeholders and the general public for their contributions. The LL Scientific

Climate change is increasingly perceived as one of the major constraints that limit agricultural productivity. Crop losses due to climate change could be direct, such as damages through flooding or storms, or indirect such as altered distribution of crop pests. The real impact of climate change at global level is yet uncertain and likely variable from one region to another. Within this context, it is difficult to predict effects of climate change, particularly when long-term datasets from the past are missing to develop and test predictive models for the future. Nevertheless, our knowledge of plant-disease interactions, population genetics of pathogens as well as crops, and examples of overwhelming establishment of new diseases in a given region provides insights into how climate change may affect disease incidence and severity. Here we report examples of pest populations which have been established across regions previously considered detrimental for their survival and yield losses associated to these pests. Faced with the uncertainty regarding the effects of changing climate on crop protection, here we propose a number of action points that, to our opinion, may help improve current plant protection strategies. Given this uncertainty, policy, research, and extension should be prepared to promote resilience vis-à-vis pests which, at the biophysical level, entails uncovering what currently makes cropping systems resilient, while at the organizational level, the capacity to adapt needs to be recognized and strengthened (Lamichhane et al 2014). Such action points include increase in human resources, development of resilient cropping systems, more focus on crop-weed competition, anticipating of risks and international monitoring, and more effort on breeding for resistance, development of biological control strategies and pest risks analysis. This diversification could be achieved by improving current plant protection practices which might help mitigate the effect of climate change in future crop protection, particularly in the EU, but also at global level. The vision presented here is that of the ENDURE European Research Group, which brings together some of Europe’s leading agricultural research, teaching, and extension institutes with a special interest in IPM.

Maize MON 87427 was developed by Agrobacterium tumefaciens-mediated transformation to express the CP4 5-enolpyruvyl-shikimate-3-phosphate synthase (EPSPS) protein, in all tissues except for the male reproductive tissues, conferring tissue-selective tolerance to glyphosate. The molecular characterisation of maize MON 87427 did not give rise to safety issues. Agronomic and phenotypic characteristics as well as compositional data of maize MON 87427 did not raise food/feed and environmental safety concerns. No differences in the compositional data requiring further safety assessment were identified. There were no concerns regarding the potential toxicity and allergenicity of the newly expressed CP4 EPSPS protein. The nutritional value of maize MON 87427 is not expected to differ from that of non-genetically modified (GM) maize varieties. There are no indications of an increased likelihood of establishment or spread of feral maize plants. Given its intended use in food and feed, interactions with the biotic and abiotic environment were not considered an issue. Risks associated with an unlikely, but theoretically possible, horizontal gene transfer from maize MON 87427 to bacteria have not been identified. The monitoring plan and reporting intervals are in line with the scope of the application for maize MON 87427. In conclusion, the EFSA Panel on Genetically Modified Organisms considers that the information available for maize MON 87427 addresses the scientific comments raised by Member States and that the maize MON 87427, as described in this application, is as safe as its conventional counterpart and non-GM reference varieties with respect to potential effects on human and animal health and the environment in the context of the scope of the application. © European Food Safety Authority, 2015.

Almost a decade ago, the European Network of Excellence ENDURE successfully linked European institutions committed to IPM research and implementation. Many subsequent European IPM projects such as PURE, build upon the outcomes and lessons learned from ENDURE. Moreover, ENDURE paved the way for C-IPM, a recently established network among 21 European countries aiming to create added value and synergies by coordinating national IPM research and extension capabilities. By making available IPM tools and practices, C-IPM contributes to meeting the challenges of European growers transitioning to mandatory implementation of basic IPM principles following the Directive 2009/128/EC on sustainable use of pesticides

International audience; Most European countries are investing in research to reduce reliance on pesticides and the risks associated with their use. They must do this to implement the principles of Integrated Pest Management (IPM) as called for by Directive 2009/128/EC. Coordinating national research and extension efforts and pooling existing re-sources can create added value and synergies. The C-IPM project creates a forum for exchange and identi-fication of IPM research and development priorities, provide recommendations on national and European research, connect existing initiatives, and coordinate joint transnational research calls.The overall goal of C-IPM is to ensure a higher level of implementation of IPM among European farmers by creating synergies from national investments in research and extension. It builds on initiatives such as the network of excellence ENDURE or the Standing Committee on Agricultural Research Collaborative Working Group on IPM, which highlighted the feasibility of generating added value via joint activities that range from information sharing and the creation of knowledge hubs to the development of joint transnational actions. It will take stock of past and ongoing research projects on IPM, such as PURE.The specific goals are to:1. Identify synergies and gaps in existing national and transnational programmes and define an IPM-specific strategic research agenda and implementation plan;2. Organise and fund joint transnational calls on IPM and minor uses;3. Ensure better translation of national and European IPM-related programmes into applicable innovation

Using mathematical model ling , the EFSA GMO Panel ha s previously quantified the risk to non - target (NT) Lepidoptera of conservation concern, potentially occurring within protected habitats, associated with the ingestion of Bt - maize pollen deposited on their host plants. To reduce the estimated larval mortality to a negligible level, an isolation distance of 20 and 30 m was recommended between protected habitats and the nearest fields of maize MON 810/Bt11 and 1507, respectively. Here , the EFSA GMO Panel refines its model predictions , accounting for new ly reported information on maize pollen deposition over long distances . For its calculations , the EFSA GMO Panel considered three exposure scenarios at a range of isolation distances, at two protection levels and for a range of lepidopteran species, including hypothetical ones, with a wide spectrum of sensitivities to Bt toxins . An analysis of various sources of uncertainties affecting the exposure of NT Lepidoptera to Bt - maize pollen was conducted, in order to provide quantitative estimates of realistic exposure levels. The EFSA GMO Panel therefore provides risk managers with a tool to estimate and mitigate the risk for NT Lepidoptera of conservation concern. In contrast to its previous o utcomes obtained for unrealistically large levels of exposure that would not be expected in practice, the EFSA GMO Panel reports here mortality estimates for a more realistic level of exposure. The EFSA GMO Panel concludes that its previous recommendation for a 20 m isolation distance around protected habitats, within which maize MON810/Bt11 should not be cultivated, remains valid. New calculations show that the previously recommended isolation distance of 30 m from the nearest maize 1507 field would still protect NT Lepidoptera with known levels of sensitivity, including the ‘highly - sensitive’ Plutella xylostella . Should hypothetical species with greater sensitivities exist, larger isolation distances would be needed to ensure the desired level of protection.

International audience; The integration of the economic, social and environmental dimensions of agriculture in a holistic assessmentframework is essential to support the development of sustainable farming. Despite the fact that some sustainabilityassessment tools fulfil this condition, none of them is suitable for handling different assessmentsituations, especially considering diverse crop production systems – arable crops, fruits and vegetables – atdifferent stages of development – research-desk prototypes (ex ante assessment) or in-field applied croppingsystems (ex post assessment). The objective of this work is to explore the possibility of sharing a sustainabilityassessment framework that can be implemented on different objects for improving (i) the communicationamong the stakeholders involved in the development of sustainable farming and (ii) the action planning interms of research as well as policy making.In this respect, the adaptation of the qualitative sustainability assessment tool DEXiPM (i) from arable crops(Pelzer et al., 2012) to other production systems and (ii) from the ex ante to the ex post assessment has representeda valuable source of ideas. Regarding the first task, three groups of experts have analyzed and modifiedthe arable crop model in order to obtain suitable tools for assessing the sustainability of field vegetables,pomefruit orchards and grapevine systems. The majority of the modifications brought have involved theparts of the model ruled by technical and scientific knowledge (e.g. determining the fuel consumption), whilefew generic modifications have been brought to the part of the model that is ruled by stakeholder priorities(e.g. relevance of biodiversity in the environmental sustainability). Regarding the second task, the modelstructure has been modified case-by-case, according to the data available in ex post assessment, to integrateprecise quantitative indicators in the qualitative framework. Two case studies have illustrated different waysof joining qualitative and quantitative data to get the best compromise between assessment precision andcomprehensiveness.This work has provided the formalization of a sustainability assessment framework suitable for different assessmentsituations. This articulates (i) a fixed core of generic agricultural sustainability issues hierarchicallyorganized that can be weighted according to stakeholders’ priorities and (ii) a set of indicators that can be flexiblyestimated according to the assessment situation. Providing a shared and generic structure of assessmentcan positively harmonize, among various crop production systems, the way for setting goals and organizingthem into a hierarchy, identifying bottlenecks and recommending adjustments towards more sustainability.

Following a request from the European Commission, the Panel on Genetically Modified Organisms of the European Food Safety Authority (EFSA GMO Panel) assessed the results of the general surveillance activities contained in the revised annual post-market environmental monitoring (PMEM) report for the 2013 growing season of maize MON 810 provided by Monsanto Europe S.A. The supplied data do not indicate any unanticipated adverse effects on human and animal health or the environment arising from the cultivation of maize MON 810 cultivation in 2013. Similar methodological shortcomings to those observed in previous annual PMEM reports were identified in the analysis of farmer questionnaires and the conduct of the literature review. The EFSA GMO Panel therefore strongly reiterates its previous recommendations to improve the methodology of future annual PMEM reports on maize MON 810. The EFSA GMO Panel urges the applicant to consider how to make best use of the information recorded in national registers in order to optimise sampling for farmer questionnaires, reiterates its previous recommendations on insect resistance monitoring and continued screening, and requests to continue reviewing and discussing relevant scientific publications on possible adverse effects of maize MON 810 on rove beetles. Also, the EFSA GMO Panel encourages relevant parties to continue developing a methodological framework to use existing networks in the broader context of environmental monitoring.

Nombreux sont aujourd’hui les projets de recherche et les expérimentations qui prospectent des voies alternatives à la protection chimique des cultures. Nous présentons ici des exemples qui sortent du cadre d’une simple substitution aux pesticides et illustrent différents aspects d’une approche système. Qu’il s’agisse de combiner des techniques de lutte complémentaires dans des stratégies intégrées, de faire évoluer le système de culture pour le rendre plus résilient, d’intervenir à des dimensions spatiales larges ou d’aménager l’environnement de la culture pour favoriser les régulations naturelles, l’objectif général est de raisonner en termes de réduction durable des populations de bioagresseurs. Cela ne va pas sans un changement de paradigme pour la recherche et le conseil, ni sans une évolution coordonnée des acteurs du système sociotechnique à laquelle les politiques publiques peuvent grandement contribuer., Today many research projects and experiments explore alternative routes to chemical crop protection. The examples presented here do not simply propose substitutes to pesticides but illustrate a larger vision: the system approach. This may mean combining complementary control techniques into integrated strategies, moving towards a more resilient cropping system, managing pests at the landscape level or manipulating habitats and cropping systems to promote natural regulations. In all cases, the general objective aims at a sustainable reduction in pest populations. This also implies a paradigm shift for both researchers and advisors, and requires coordinated changes in stakeholders strategies within the socio-technical regime, changes to which public policies can greatly contribute.

Dans le dernier demi-siècle, les territoires et les exploitations agricoles se sont de plus en plus spécialisés. Or, on sait aujourd’hui qu’une diversification des cultures serait nécessaire pour réduire l’usage des intrants (pesticides, engrais azotés, eau d’irrigation) et les nuisances environnementales associées. Cet article tente de mettre au jour les freins à la diversification des cultures, qui se manifestent à différents niveaux des filières agro industrielles, afin de dégager des pistes d’action pour les politiques publiques. Nous mettons en évidence un verrouillage technologique autour des espèces dominantes, qui bloque ou tout au moins handicape fortement le développement des espèces mineures. Ce verrouillage est caractérisé par un grand nombre de freins interconnectés, depuis la disponibilité de variétés améliorées et de méthodes de protection phytosanitaire, la rareté des références quantifiées sur les successions incluant ces cultures, la difficulté des apprentissages à acquérir, jusqu’aux contraintes logistiques au niveau de la collecte et aux difficultés de coordination au niveau des filières émergentes, dont les acteurs se connaissent souvent mal. Le verrouillage technologique autour des grandes espèces n’est cependant pas une fatalité. L’article dégage une série de leviers d’action mobilisables pour inciter les acteurs à insérer, dans leur système productif, une plus grande diversité d’espèces cultivées. Il adresse un ensemble de recommandations aux pouvoirs publics en matière de politique agricole, d’orientation de la recherche et d’appareil statistique.

International audience; Cultivation of GM crops with herbicide tolerance is mostly associated with changes in crop and weed management, like simplified rotations, simplified tillage and change from selective herbicides to the broadband glyphosate. All of these management practices decrease weed densities in crops and change their composition. Although weeds cause yield loss and harvest problems, they are an important part of arable biodiversity and offer food and habitat for different groups of animals. A simulation study was conducted to analyse indirect effects of intensified cropping in GM maize on biodiversity. The dynamic crop: weed model FlorSys was used to simulate weed densities and composition of common cropping systems and probable (GM) cropping systems in two regions of France and Spain. Results were translated into a set of biodiversity and harmfulness indicators. The presentation will show that the change from selective herbicides to glyphosate (which GM maize is tolerant to) has only smaller effects on biodiversity compared to simplified rotations. Change from a soybean-maize-wheat-maize rotation to a continuous maize cropping decreases weed species richness as well as food resources for birds, beetles and pollinators strongly. The total abandonement of tillage strongly increased biodiversity indicators in our simulation, but was associated also with high damage, and can therefore not be recommended to farmers.

According to E.U. regulations, the maximum allowable rate of adventitious transgene presence in non-genetically modified (GM) crops is 0.9%. We compared four sampling methods for the detection of transgenic material in agricultural non-GM maize fields: random sampling, stratified sampling, random sampling + ratio reweighting, random sampling + regression reweighting. Random sampling involves simply sampling maize grains from different locations selected at random from the field concerned. The stratified and reweighting sampling methods make use of an auxiliary variable corresponding to the output of a gene-flow model (a zero-inflated Poisson model) simulating cross-pollination as a function of wind speed, wind direction, and distance to the closest GM maize field. With the stratified sampling method, an auxiliary variable is used to define several strata with contrasting transgene presence rates, and grains are then sampled at random from each stratum. With the two methods involving reweighting, grains are first sampled at random from various locations within the field, and the observations are then reweighted according to the auxiliary variable. Data collected from three maize fields were used to compare the four sampling methods, and the results were used to determine the extent to which transgene presence rate estimation was improved by the use of stratified and reweighting sampling methods. We found that transgene rate estimates were more accurate and that substantially smaller samples could be used with sampling strategies based on an auxiliary variable derived from a gene-flow model.

National audience; Les adventices sont à la fois un bioagresseur très nuisible pour la production agricole, et essentielles pour la biodiversité des paysages agricoles. Leur gestion doit se raisonner à long terme puisque les semences survivent pendant plusieurs années dans le sol, et la dynamique adventice dépend d'une multiplicité de facteurs (système de culture, pédoclimat). De plus, les semences se dispersent dans les paysages, et la dynamique adventice d'une parcelle agricole peut ainsi être influencée par les pratiques des parcelles voisines mais également par les habitats semi-naturels. Par conséquent, l'évaluation et la conception de stratégies de gestion d'adventices se font souvent à l'aide de modèles. Dans la présente étude, nous avons adapté le modèle de dynamique adventice existant FLORSYS (Colbach et al.) pour simuler (1) plusieurs parcelles voisines, (2) des habitats hors-champ comme les bandes enherbées et les bordures de route, (3) la dispersion de semences adventices par des vecteurs naturels (Thomson et al., 2011). Nous avons ensuite réalisé une étude de simulation sur des extraits de paysages constitués de 4-9 parcelles et de bandes enherbées, comparant différents systèmes de culture à base de maïs, se distinguant par la diversité des cultures dans la rotation, la fréquence de labour et de travail du sol, le programme herbicide, etc... Les premiers résultats ont permis de lier la progression des adventices dans le "mini-paysage" aux traits des espèces, montrant que la densité dans les parcelles voisines est bien plus importante pour la dispersion qu'un mode de dispersion à longue distance (ex anémochore ou zoochore), des semences légères ou des plantes de grande taille. L'étude des différents systèmes de culture montre que par exemple que la simplification des rotations réduit la contribution de la flore adventice à la biodiversité (richesse et équitabilité de la flore, offres trophiques pour oiseaux, carabes, abeilles) mais réduit aussi la nuisibilité pour la production agricole (perte de rendement, pollution de récolte, problèmes techniques de récolte, salissement du champ). Au contraire, l'abandon du travail du sol favorise la biodiversité mais augmente la nuisibilité. Références : Colbach N, Biju-Duval L, Gardarin A, Granger S, Guyot SHM, Mézière D, Munier-Jolain NM and Petit S. The role of models for multicriteria evaluation and multiobjective design of cropping systems for managing weeds. Weed Research, in press Thomson FJ, Moles AT, Auld TD and Kingsford RT (2011) Seed dispersal distance is more strongly correlated with plant height than with seed mass. Journal of Ecology 99: 1299–1307

hal-01811436; Evolution des raisonnements agronomiques et économiques pour accompagner les changements des systèmes techniques dans les exploitations agricoles

La diversification des cultures peut permettre de réduire les impacts environnementaux de l’activité agricole. Cet article synthétise une étude récente sur le verrouillage économique et technique qui limite les opportunités de diversification en France. Il analyse ensuite en quoi la PAC de 2014 peut contribuer à alléger les obstacles à la diversification et fait des propositions d’améliorations du dispositif français., Crop diversification can contribute to alleviate the environmental impacts of agricultural production. This article provides a synthesis of a recent study on the economic and technology lock-in which limits crop diversification opportunities for French farmers. It analyses how the 2014 CAP reform can help to remove obstacles to crop diversification. Proposals and improvement recommen- dations are made for the French case.

Crop diversification is often presented as a way to improve the sustainability of agricultural production systems (reduction in the use of inputs and environmental damage resulting from their excessive use - pesticides, fertilizer, water). However, despite these benefits and various incentive programs, crop diversification is gaining little ground in France. The objective of this study is to identify: i) the main obstacles to crop diversification at agro-industrial supply chain and farm levels; ii) the levers that can be employed to encourage these stakeholders to integrate greater crop diversity within their production system. An interdisciplinary analysis framework was used, integrating farming system agronomy, sociotechnical transition approach and new institutional economics. This theoretical framework is centred on the "technological lock-in" theory, derived from the innovation economy, and socio-technical transition theory, which proposes potential "break-out" avenues. This framework is tested on twelve crop diversification cases studies with three in-depth analyses. Our results show that the socio-technical system organized on the basis of dominant crops and the simplification of cropping plans is therefore an obstacle to the development of diversification crops as a result of various closely interlinked processes: (i) genetic progress that is less rapid than for "major crops"; (ii) a lack of crop protection solutions (agrochemicals one but also genetic and agronomic ones); (iii) a shortage of technical references concerning minor crops to explain low yield or quality defects at regional scale; (iv) a competition with "major crops" on the raw material market not only due to price but also accessibility and homogeneity differences (v) the diversity of coordination methods between the different stakeholders in the supply chains Finally, to encourage the development of diversification crops, it would appear to be essential to act simultaneously on three levers supported by public action: (1) Promotion of new market outlets, (2) Coordination of stakeholders and structuration of supply chains and (3) getting R&D, advisory and plant breeding actors involved on a national nd regional level to develop innovative technologies and varieties.

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International audience

Methods have been developed to detect transgenic presence in non-GM maize fields. These detection methods may be used to determine whether the regulatory transgenic rate threshold (0.9%) is exceeded, but the results are likely to depend on the grain sample size and on the sampling strategy used to collect grains within agricultural fields. Until now, no clear sampling strategy and sample size have been defined for implementing detection methods.[br/]This study aims to compare four types of sampling strategies for maize grains in agricultural fields—i) random sampling, ii) systematic sampling, iii) stratified sampling, and iv) regression sampling.The first approach simply randomly samples maize ears in the considered field. The second approach consists of selecting ears according to a regular grid. The two final approaches use an auxiliary variable correlated with the real transgene distribution in order to define strata with contrasted presence rates or to reweight a sample of ears selected at random.[br/]The auxiliary variable considered in this study corresponds to the output of a gene-flow model simulating cross-pollination in function of wind speed, wind direction, and distance to the closest GM maize field. Data collected in the Montargis (France) experiments in 1998 and 1999 were used to compare the four sampling strategies and to determine the sample size (i.e., number of ears) required to detect transgene presence with a good level of accuracy.[br/]Results showed that a sample of 2,000 ears is needed to reach a sensitivity or a specificity of 0.95 with random sampling when the true presence rate differs by 0.2% from the regulatory threshold of 0.9%. We showed that this sample size could be strongly reduced (up to 25 to 100 ears depending on the siteyear) by using stratified sampling. Regression led to intermediate sample sizes, and systematic sampling was found to be verysensitive to the position of the first sampled plant.

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