About
198
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Introduction
Stéphane Cordeau currently works at the Agroécologie , French National Institute for Agricultural Research. Stéphane does research in Ecology and Agronomy.
am investigating the impact of cropping systems on weed communities. I mainly focus on the effect of cropping systems in 3 gradients: (i) reduction of tillage (from conventional tillage to continuous no-till); (ii) increasing use of cover-crops (from cropping systems containing only cash crops to all ranges of cover-cropping); (iii) reduction of herbicide. The fundamental objectives of my research are to understand how weed communities evolve (through abundance, richness, biomass, evenness, and traits) in systems where farmers reduce tillage, use cover crops, and tend to reduce their reliance on herbicide.
Current institution
Additional affiliations
January 2011 - September 2012
January 2011 - September 2012
October 2015 - September 2016
Position
- Researcher
Description
- Visiting Scholar in the Sustainable Cropping Systems Lab of Matthew R. Ryan, working on Weed Management in Organic No-Till and Cover Crop-based cropping systems.
Publications
Publications (198)
Résumé : L’étude visait à (i) identifier les pratiques de gestion des couverts pour réduire les adventices dans les cultures suivantes et (ii) quantifier les effets intentionnels ou non de méthodes de destruction des couverts/adventices/repousses. Les couverts d’interculture ont significativement réduit les adventices en interculture de 68 % à 94 %...
According to the Resource Pool Diversity Hypothesis (RPDH), increasing cropping system diversity (e.g., crop rotation, fertility sources, and weed management) should increase soil resource pool diversity, and mitigate weed‐crop competition intensity. Despite the growing interest in cover crop mixtures to provide weed control, our study is the first...
Premise
Restoration of seminatural field margins can elevate pollinator activity. However, how they support wild plant gene flow through interactions between pollinators and spatiotemporal gradients in floral resources remains largely unknown.
Methods
Using a farm‐scale experiment, we tested how mating outcomes (expected heterozygosity and paterni...
Knowledge of how agricultural management interacts with weed seed banks and emergent weed communities is crucial for proactive weed management. Though studies have detailed how differences in disturbance and nutrient applications between organic and conventional herbicide‐based systems affect weed communities, few have focused on these same factors...
Integrated weed management (IWM) promotes the combination of non-chemical techniques to achieve sustainable weed control while reducing the reliance on herbicides. However, IWM strategies reducing both herbicide and tillage intensity remain unsatisfactory, leading to weed-induced yield loss. In this study, five different IWM strategies were impleme...
Conservation agriculture (CA) is an approach to farming that is defined by three principles: (1) minimal soil disturbance (no-till), (2) crop diversity in time and space, and (3) soil coverage by crop residues and/or cover crops. These principles provide a roadmap to protect and improve soil. However, the narrow criteria for defining CA may fail to...
Temporal crop diversification could reduce pesticide use by increasing the proportion of crops with low pesticide use (dilution effects) or enhancing the regulation of pests, weeds and diseases (regulation effects). Here, we use the French National DEPHY Network to compare pesticide use between 16 main crops (dilution effect) and to assess whether...
Cover crops are plants grown to provide regulating, supporting, and cultural ecosystem services in managed environments. In agricultural systems, weed suppression services from cover crops can be an important tool to promote sustainability as reliance on herbicides and tillage for weed management has caused pollution, biodiversity loss, and human h...
Cover crops, as either a living plant or mulch, can suppress weeds by reducing weed germination, emergence and growth, either through direct competition for resources, allelopathy, or by providing a physical barrier to emergence. Farmers implementing conservation agriculture, organic farming, or agroecological principles are increasingly adopting c...
Cover crops as living plant or mulch can suppress weeds by reducing weed germination, emergence and growth, either through direct competition for resources, allelopathy, or by providing a physical barrier to emergence. Farmers implementing conservation agriculture, organic farming or agroecological principles are increasingly adopting cover crop as...
Les plantes ne poussent pas par hasard », « si elles sont présentes ici c'est qu'elles s'y plaisent », « elles nous indiquent quelque chose », et « elles poussent pour corriger des déséquilibres » engendrés par nos pratiques agronomiques. Vous qui cultivez, conseillez, enseignez ou simplement vous intéressez à ces formes d'agricultures qui regarden...
The carry-over effect of cover crops on weeds and crop productivity in the subsequent crops has been related to cover crop composition and cover crop termination methods but their interaction with soil resource availability remains poorly documented, as well as the relative importance of each of these factors. This study investigated the effect of...
Context: Little is known about the long-term contribution of cover crops to weed management in tillage-and herbicide-based systems. Research questions: Do cover crops mainly filter weed species capable of setting seeds during the fallow period? Can cover crop biomass productivity explain differences in weed suppression among cover crop species? Doe...
The balance of pollination competition and facilitation among co‐flowering plants and abiotic resource availability can modify plant species and individual reproduction. Floral resource succession and spatial heterogeneity modulate plant–pollinator interactions across ecological scales (individual plant, local assemblage, and interaction network of...
Conservation agriculture (CA) relies on three fundamental and inseparable pillars: no soil disturbance, diversified crop rotations, and permanent soil cover. Nevertheless, few studies have evaluated the interactive effect of these three fundamental pillars on a multicriteria basis. Here, we mobilize data from the French AGROSYST database, which gat...
La gestion des plantes adventices constitue une problématique majeure en céréales à paille. Depuis le développement des premiers herbicides de synthèse, ce levier a été largement utilisé à travers le monde, permettant une gestion efficace et peu coûteuse des adventices. Cependant, dans un contexte de réduction des intrants de synthèse, la recherche...
There is a pressing need for research guiding the design and management of multifunctional landscapes that combine the delivery of production services and that of other ecosystem services. Arable weeds are an interesting model as they can impact negatively crop production but also contribute to maintain pollination and pest control services. Here,...
La régulation biologique des adventices par les couverts végétaux cultivés peut impliquer différents mécanismes. La compétition pour les ressources est le mécanisme considéré comme prépondérant dans la régulation des adventices par les couverts végétaux. L’allélopathie pourrait également jouer un rôle mais ses effets au champ sont difficiles à démo...
Cet article synthétise les connaissances sur les effets des couverts végétaux d'interculture et des pratiques culturales, associées au système de culture dans lesquels ils sont insérés, sur les adventices. En effet, les pratiques associées à la mise en place des couverts influent sur la flore adventice qui s'établit dans les parcelles et modifient...
Les couverts végétaux peuvent fournir de nombreux services écosystémiques dont la régulation biologique des adventices, mais ce n'est pas le service écosystémique qui est principalement mentionné par les agriculteurs. En revanche, il y a une connaissance experte très vaste des couverts végétaux, car les agriculteurs expérimentés ont déjà optimisé l...
L’étude des systèmes écologiques est souvent rendue difficile car certaines composantes échappent à une observation parfaite, comme les trajectoires d’animaux en mouvement ou la banque de graines des plantes. La modélisation statistique permet de traiter efficacement ces composantes cachées en utilisant le cadre des variables latentes, qui permet d...
Vineyards are an appropriate model for testing the filtering effect of management practices on weed communities, as a wide range of practices (tillage, herbicides and mowing) is implemented. The aim of this study is to highlight which trait values are selected by each practice in different environmental conditions, with special references to Grime'...
The use of multiple ecological weed management tactics may be an effective solution to weed management challenges associated with reducing tillage. An experiment was conducted to assess how soybean Glycine max (L.) Merr. density and cereal rye Secale cereale L. mulch biomass affected weed suppression and community assembly in no‐till production. So...
It is now essential to reduce the negative impacts of weed management and especially herbicide use. Weed-suppressive crop species/varieties hold promise for integrated and sustainable weed regulation. Competition for resources and allelopathy are the two main underlying mechanisms. Unlike competition, which is well studied and established, allelopa...
We reviewed the timing of the peak rate of emergence for 15 problematic weed species as well as ways to use this knowledge to improve control. Much of the previous literature modeled emergence based on growing-degree-days. For these models, we input average temperature data from several zones of Northeast USA. Within species, model-predicted peak e...
La gestion des adventices constitue une problématique majeure en céréales à paille afin de mener la transition agroécologique de l’agriculture française. Le choix de variétés ayant une capacité de compétition élevée vis-à-vis des adventices a fait l’objet de peu d’investissements et généré peu de résultats probants, notamment du fait de difficultés...
Agroecological farming uses crop and non‐crop plant biodiversity to promote beneficial insects supplying pollination and biocontrol services to crops. Non‐crop plants (sown or weeds) are integral to supporting these beneficial insect species interactions. How the uplift of biotic complexity by agroecological management (crop diversification, ecolog...
Cover crop (CC) mixtures appear as a promising agroecological tool for weed management. Although CC supress weed growth by competing for resources, their suppressive effect under contrasting levels of soil resource availability remains poorly documented. A two field:year experiment was conducted to investigate the weed suppressive effect of four CC...
Conservation agriculture (CA) allows farmers to reduce costs and enhance soil health, but tends to increase weed infestation and associated crop yield loss, and/or herbicide use. We investigated how much tillage reduces weed infestation and yield loss, and which systems and weed species are the most affected by tillage suppression. We collected far...
Reduction in herbicide use will trigger changes in weed communities. Improving our capacity to identify farming management options that will lead to weed communities offering interesting trade-offs of functions is thus timely. Functional approaches are offering a robust framework to quantify and understand the underlying mechanisms that link farmin...
Conservation agriculture (CA) relies on three fundamental pillars [1,2]: crop species diversification (in time and space such as crop rotation and crop association, respectively; at least three different crops according to FAO [3]); permanent soil organic cover (more than 30% of the ground area must be covered immediately after the direct seeding o...
Les agroéquipements et le numérique sont des leviers essentiels pour développer des
systèmes de culture sans pesticides. Des innovations en matière de précision d’exécution
et d’adaptabilité des équipements sont attendues. En parallèle, le développement
des capteurs va permettre d’améliorer la surveillance des bioagresseurs, mais également
celle de...
Cropping system (CS) diversification appears as a promising solution to increase CS sustainability. However, weed community response to different options of CS diversification remains poorly documented. Moreover, these effects are expected to be more pronounced in experimental than commercial farms because experimental farms explore more diverse co...
In this chapter, the authors present a hidden Markov models (HMM) of local dynamics (within a patch) and regional dynamics (between patches) for an annual plant with a dormant stage, combining all of the advantages of existing models. Abundance class data will be taken into account, as will the effect of adult plants on the seed bank, alongside exp...
To reduce reliance on herbicides and maintain crop productivity, integrated weed management (IWM) seeks to optimize synergies between diverse sets of weed management practices combined at the cropping system scale. Nevertheless, data on weed community response to the long-term implementation of IWM practices remain scare. Here, we assessed the effe...
Given the negative environmental effects of conventional agricultural techniques, the need for biodiversity-friendly agriculture systems that rely more on ecosystem services and less on chemical inputs is becoming increasingly urgent. In this paper, we focus on crop protection strategies that are alternatives to the use of pesticides. Diversificati...
The biological control of weeds is receiving increased attention worldwide because it could help farmers reduce herbicide use. In this chapter, we review available knowledge on two biotic interactions that may lead to natural weed control, namely weed-sown plant interactions (competition, allelopathy) and weed-insect interactions (herbivory, graniv...
To better understand the changes in weed communities following the adoption of conservation agriculture (CA), we investigated the functional composition of weed communities in fields implementing CA continuously from 1 to 21 years. Weed surveys were conducted in 100 winter wheat fields of 53 farmers in the Bourgogne-Franche-Comté region, Eastern Fr...
Cover crop mixtures have the potential to provide more ecosystem services than cover crop monocultures. However, seeding rates that are typically recommended (i.e. seeding rate of monoculture divided by the number of species in the mixture) are non‐optimized and often result in the competitive species dominating the mixture, and therefore limiting...
Agroecological transition is now seen as a pathway with many opportunities to improve the sustainability
and resilience of agricultural systems. Many agricultural policies and recovery plans emphasize this
pathway.
Agroecology, by maximizing the use of ecological processes and particularly positive interactions
between plants and between plants and...
There is a pressing need for indicators and methods to quantify the provision of ecosystem services as a pre-requisite to identify management options that optimize trade-offs between services. Arable weeds provide multiple services and are thus a good model to evaluate such trade–offs. This flora provides trophic resources (flowers or seeds) that s...
The widespread loss of weed diversity and associated ecosystem functions is raising important concerns. Field edges could play a major role in the maintenance of weed functional diversity in arable landscapes as these habitats still harbour high weed diversity, owing to either a reduced farming management intensity and/or to a spillover of species...
Agroecological principles are to value the ecosystemic services delivered by enlarged planned and natural biodiversity to sustain regulation and support services for agricultural production. Maximizing the biological functions provided by biodiversity requires to profoundly re-design agricultural systems, considering the management of both cropping...
Agricultural impacts of climate change include direct effects on crop plants and indirect effects, such as changes to the distributions and competitiveness of weed species. In the northeastern United States, warming temperatures are likely to result in periods of soil moisture deficit and changes to weed communities. Ivyleaf morningglory (IMG, Ipom...
European Conservation Agriculture Federation (ECAF)
Weed communities can be influenced by nutrient availability, nutrient form (e. g., ammonium vs. nitrate), amendment timing, amendment type (e.g., organic vs. inorganic), and by immigration of seeds during amendment applications. The objective of this research was to compare the long-term effect of different fertility treatments in a corn ( Zea mays...
Throughout Europe, Cirsium arvense is the most problematic perennial weed in arable crops, whether managed under organic or conventional agriculture. Non-chemical control methods are limited with partial efficacy. Knowledge is missing on their effect across a wide gradient of cropping systems and pedoclimates. To achieve effective Cirsium arvense m...
Over the last decades, land management options have been investigated that aim at enhancing services to agriculture delivered by biodiversity and its associated biotic interactions. Such services can be promoted through land management strategies ranging from in-field single agricultural practices, long-term strategies compiling these agricultural...
Cover crops (CC) have been proposed as a promising ecological tool to manage weeds and increase crop productivity. We hypothesized that the repeated use of CC could increase crop yield directly through nitrogen release and/or indirectly through a modification of weed communities. Data were collected on CC biomass, weed biomass, weed community compo...
Crop diversification, both in time and in space, is essential for agroecological pest management. Process-based weed dynamics models are valuable tools to investigate this issue. Indeed, (1) weeds are the most harmful pest in arable crops and are essential for biodiversity, and (2) the processes driving crop-weed interactions are similar to those f...
The growing recognition of the environmental and health issues associated to pesticide use requires to investigate how to manage weeds with less or no herbicides in arable farming while maintaining crop productivity. The questions of weed harmfulness, herbicide efficacy, the effects of herbicide use on crop yields, and the effect of reducing herbic...
If you're interested to take part in the monitoring network of Vulpia myuros and other Vulpia species, send us your observations or contact us.
Cet article présente les travaux menés dans le cadre du projet ENGAGED. Ce projet a été initié en 2016 à la demande d'agriculteurs normands qui pratiquent le Semis Direct sous Couvert Permanent de légumineuses pérennes (luzerne, trèfle) dans des rotations avec colza, blé, orge. Il vise à construire des systèmes de cultures basés sur la couverture p...
FRANCAIS:
Concilier la productivité des cultures et le maintien de la biodiversité est l'un des principaux défis de l'agriculture mondiale. Nous avons testé les hypothèses selon lesquelles (i) toutes les communautés adventices ne génèrent pas de pertes de rendement et (ii) que des communautés adventices plus diversifiées peuvent atténuer les pertes...
Résumé : Pour comprendre comment gérer les adventices avec peu ou pas d'herbicides en grandes cultures, étudier la nuisibilité des adventices, l'efficacité et les effets des herbicides et de leur réduction sur le rendement est nécessaire. Cette question a été étudiée depuis des années mais les résultats apparaissent souvent contradictoires. Notre a...
Vulpia myuros is an annual grass species of Mediterranean origin, which has achieved
a global distribution. It is a fast-growing species, with high colonisation and competitive
abilities. This species is considered an invasive weed in most countries where it
has been introduced, with highly negative economic impact where it now dominates.
It is inc...
In Europe, conservation agriculture (CA) is currently challenged by higher weed pressure, potential glyphosate ban and reduced crop yield. Based on preliminary results and a critical analysis, we provide insights on how to assess the effect of introducing different levels of tillage intensity, after a long-term CA sequence, on weed communities and...
Multiple anthropogenic challenges threaten nature’s contributions to human well-being. Agricultural expansion and conventional intensification are degrading biodiversity and ecosystem functions, thereby undermining the natural foundations on which agriculture is itself built. Averting the worst effects of global environmental change and assuring ec...
In arable farming, weeds provide important floral and seed resources that have the potential to support the provision of ecosystem services such as pollination or pest control. Estimating the production of these weed resources in the landscape is however not trivial as large-scale surveys of weed communities are usually conducted once in the season...
Reconciling crop productivity and biodiversity maintenance is one of the main
challenges of agriculture worldwide. Weed management is recognized to be a
key point for ecological intensification in agriculture because weeds can
generate severe yield losses but also represent the base of agricultural trophic
networks. Research in weed science has oft...
The weed soil seedbank is of interest in agroecosystems as a major source of weed infestation in fields and as a reservoir of plant and seed‐feeder diversity. A seedbank is a characteristic of annual plants and has been the focus of numerous studies, as it reflects the past aboveground vegetation and is the reservoir of the future vegetation. There...
La gestion des adventices par les couverts végétaux apparaît comme une solutionagroécologique avantageuse. La question du choix des espèces se pose,mais aussi de l’intérêt des mélanges.
Farmers and farm advisors need a decision support system (DSS) to develop multiperformant weed management strategies adapted to economic, social and environmental stakes and farmers' constraints. We worked with future users, farmers, and crop advisors to define the uses and type of DSS they needed, via an online survey, group meetings and workshops...
Cover crops are increasingly being used for weed management and planting them as diverse mixtures has become an increasingly popular strategy for their implementation. While ecological theory suggests that cover crop mixtures should be more weed-suppressive than cover crop monocultures, few experiments have explicitly tested this for more than a si...
A field experiment in central New York evaluated the effect of sunflower (Helianthus annuus L.) density on weed biomass and yield in organic sunflower production. Two varieties of sunflower, Badger DMR and N5LM307, were seeded at 6.1 and 8.6 seeds m⁻², and grown using organic management practices at one site in 2016 and two sites in 2017. Sunflower...
Switching from intensive herbicide-based to agroecological weed management needs models to explore the vast range of possible combinations of cropping techniques, to assess long-term effects and weed (dis)services. FLORSYS is a mechanistic "virtual field" model simulating daily weed and crop growth and reproduction over the years, on which arable c...
Les agriculteurs présents dans une même situation de production peuvent différer dans leurs objectifs et donc leurs pratiques. Afin de tester l'effet d'une pratique particulière (ex. désherbage chimique) sur la communauté adventice, il est donc nécessaire de tenir compte de l'ensemble des autres pratiques, formant une stratégie agricole. Nous avons...
Une enquête nationale ayant recueilli 1320 réponses (839 analysées dans cet article), dont 56% d'agriculteurs, 26% de conseillers, 14% de techniciens/expérimentateurs et 4% de chercheurs, a permis de sonder leur perception des adventices. Les effets positifs des adventices ont moins d'importance aux yeux des sondés que leurs effets négatifs. Pour l...
Favoriser la régulation des adventices par compétition peut être un levier pour réduire le recours aux herbicides. Cependant, les agriculteurs se heurtent à l'absence d'outils et de conseils pour les aider à rationaliser le choix des espèces/variétés cultivées à semer dans cette optique. Ceci nécessite une meilleure connaissance de l'aptitude à la...
Un essai pluriannuel en semis-direct a testé l'effet de couverts (quatre mélanges comparés à du sol nu) sous divers niveaux de ressources (en azote et en eau) sur la flore adventice et sur les cultures suivantes de la succession (orge de printemps puis lin d'hiver) conduites sans fertilisation et sans désherbage. Une augmentation du nombre d'espèce...
Afin de concevoir des systèmes agricoles durables et économes en herbicides, il est indispensable de comprendre les relations entre usage d'herbicides, niveau d'infestation par les adventices et pertes de rendement. Comme les agriculteurs raisonnent l'utilisation des herbicides en fonction de la flore et de leurs autres pratiques (ex. travail du so...
En Agriculture de Conservation des Sols (ACS), la perturbation minimale du sol est l'un des trois prin-cipes. Si l'impasse se fait sentir mieux vaut repenser le système que de laisser le mur se rapprocher à grands pas. Trois types de gestion d'interculture (Labour, travail superficiel (TCS) et semis direct avec glyphosate (SD)) ont été comparés sur...
La diversification des cultures est un levier majeur de gestion agroécologique des bioagresseurs. Ce papier illustre avec l'exemple de FLORSYS le rôle des modèles mécanistes de dynamique des adventices pour synthétiser les connaissances, les appliquer à la conception de systèmes de culture, et les transférer vers les acteurs. Des cas d'étude illust...
