Adventices du tournesol : la nuisibilité n'est pas linéaire

Prod 2018-41 EA GESTAD INRANational audienceUne étude a analysé la relation entre le rendement du tournesol et la densité d’adventices présentes sur des parcelles n’ayant subi aucun désherbage. La nuisibilité des adventices croît avec la densité des adventices, mais pas de façon proportionnelle. En particulier, la nuisibilité directe ne s’exprime pas à faible densité d’adventice

Nuisibilité des adventices en colza : un rendement impacté par les fortes infestations

Prod 2018-251 EA GESTAD INRANational audienceL’analyse des parcelles témoins non désherbées d’essais menés sur colza montre que le rendement de la culture est impacté plus ou moins fortement selon la densité des adventices, d’une part, et le type d’espèces adventices, d’autre part

Travail du sol et couverts : quels effets sur les adventices ?

Prod 2019-155 EA GESTAD INRANational audienceEn grandes cultures, réduire l’usage des herbicides sans perte inacceptable de rendement implique de maîtriser la flore adventice en faisant jouer diverses méthodes. Parmi elles, les couverts végétaux (à l’interculture ou durant la culture) et le mode de gestion du sol peuvent avoir une influence et interagir. Dans le cadre du projet ANR CoSAC, les résultats d’essais préexistants (essais systèmes factoriels annuels, factoriels de longue durée) ont été réanalysés pour évaluer les effets des facteurs « couverts » et « travail du sol ». La présence et le type de couvert jouent un rôle sur les adventices et repousses durant la période de présence du couvert. Leur influence dans la culture suivante est minime, sauf dans le cas du semis direct. Le labour est efficace sur graminées. En non-labour, le semis direct sans bouleversement du sol limite mieux les levées d’adventices que le travail du sol superficiel

Foreword

This collection, entitled ‘The Poetics of Framing, Performing Frames in the Visual Arts,’ follows in the footsteps of the spatial turn that began to reassess the relationship between culture and space in the 1970s, and has led to new interpretations not only of social and geographical space, but also of artistic delineation, production, and use of space. It is more specifically interested in the question of the frame, both as a parergon and as an artefact. The parergon may rub against the er..

Étude de l’effet du travail du sol et des couverts sur les adventices dans des contextes de production variés

EAGESTAD INRAL’objectif de cette synthèse de résultats d’essais est d’analyser la diversité de réponses des adventices aux couverts associés ou d’interculture couplés à différents niveaux de travail du sol (allant du non travail du sol au labour). Des essais analytiques permettent de quantifier d’une part l’effet des couverts et d’autre part celui du travail du sol. Certains de ces essais analytiques et des essais systèmes sont utilisés pour appréhender l’interaction entre les facteurs travail du sol et présence de couverts. Cette présentation développera en particulier l’effet des couverts dans différents systèmes de production : couverts associés au colza, couverts d’interculture dans les systèmes céréaliers français et dans les systèmes légumiers américains

Le faux semis : identifier les clés du succès

Stale seedbeds (or false seedbeds) aim to trigger weed seed germination during summer fallow in order to reduce the weed seed bank. This tillage operation must be shallow (less than 5 cm) and create a firm seedbed without clods. Field trials did not show any correlation between weed emergence during summer fallow and weed emergence in the following crop. Weed emergence observations underestimate the efficacy of stale seedbeds because they disregard seeds that germinate without emerging. Stale seedbed efficacy depends on soil moisture and seed dormancy level at the time of the operation. This technique must be combined with other techniques such as delaying the sowing of the following crop. This strategy was successful in simulations with the FLORSYS weed dynamics model. In an oilseed rape-winter wheatwinter barley rotation, stale seedbed the most reduced the weed infestation in the following crops if it was carried out in mid-August. Later operations risk to increase weed emergence after the sowing of the earliest winter crops.Le faux semis consiste à faire germer des adventices pour les détruire ultérieurement avant le semis d’une culture. Cette opération doit être superficielle (moins de 5 cm) et générer un lit de semences bien affiné et rappuyé. Les essais ne montrent pas de lien entre les levées d’adventices observées pendant l’interculture et celles observées dans les cultures. Le comptage des levées ne prend pas en compte les semences germées qui meurent avant de lever. Par ailleurs, l'efficacité du faux-semis dépend énormément de l'humidité du sol et de la dormance de l'espèce adventice à la période où il est réalisé. L'effet du faux semis est donc partiel et variable, d’'où l'intérêt de le combiner avec d'autres techniques préventives, comme le décalage de la date de semis de la culture. Cette stratégie est confirmée par des simulations avec FLORSYS qui montrent que dans une rotation colza-blé-orge d’hiver, l’effet des faux semis sur la flore des cultures suivantes atteint son maximum pour des interventions de mi-août. Les opérations plus tardives risquent de faire lever les adventices après le semis de céréales les plus précoces

Spot spraying in oilseeds and protein crops

International audienceCurrently, spraying chemical products in agriculture became the main means of weed controlbecause this cultural practice is very fast, inexpensive and very effective. However, awarenessof their negative impacts (environment, human health) requires thinking about new technicaland agronomic solutions. New technologies are promising techniques for a site-specific weedmanagement through the development of localized spraying.Some sprayers (often small width) located on the row may be able to answer thoseexpectations but they are most often expensive. In this context, the objective of the project“PLEVOP” (development of spot sprayer in oilseed and protein crops), proposed byTerres-Inovia, is the operational development in arable crops of a spot sprayer located on therow through model crops: the rapeseed and sunflower. The aim is to complete the chemicalweeding on the row by mechanical weeding (hoeing) on inter-row. Working with amanufacturer, MARECHAL, the objectives of the project are to 1) explore the potential of thissystem, 2) define its use conditions (volume, nozzle type, nozzle height, speed of passage, highwork output ...) and the effectiveness of this technique, in order to provide quality advice tofarmers.Through the tests conducted we want to 1 / know the influence of the type of guidance (GPSRTK,tracer wheels, vision ...) on this type of spray and 2 / study the biological efficiency onweeds by comparing it to that full treatment.Finally, to qualify the environmental gain (reduction of use and impact) and to evaluate thepracticability and the economic balance will be undeniable assets to accompany the farmer innew agri-environmental practices

Localized spraying in oilseeds rape crop with a conventional boom sprayer

National audienceAs a part of ECOPHYTO plan established by the French government to reduce the use of chemical plant protection products (PPP), specific spraying equipment are needed, for example to spray only the row of the crop. Often these devices have small spray boom widths and they are very expensive. The objectives of the project “PLEVOP” (development of in-row sprayer in oleaginous crops and protein crops), proposed by the technical Institute Terres-Inovia, are to define the conditions for successful localized post-emergence spraying for the herbicide application on the row using large width devices. This work is carried out in connection with a manufacturer of agricultural equipment (the Marechal company), an agricultural cooperative (CAL) and a French public Institution of Higher Education (AgroSup Dijon). The first year, experiences were conducted on oilseed rape crops using GPS-RTK as guidance system embedded on the tractor; the second year, trials were realized on oilseed rape and sunflower using a camera interface placed on the boom as guidance system. Three weeding strategies practices are compared: "full herbicide treatment" vs. "herbicide treatment on the row + inter-row hoeing" and a "no treatment". After weed counting and identification, we evaluated the biological efficiency on weeds and the effectiveness of such operations. Moreover, working with a conventional sprayer for a localized spraying, we have developed an automatic calculator tool to help farmer to determine the required amount of herbicide and water depending on its use conditions (nozzle type, nozzle height, speed of passage, boom height, field size, etc...). Oilseed rape: First trial of localized herbicide treatment with a conventional boom sprayer Experiences were conducted in the Lorraine region in France in 2017-2018 on oilseed rape crop. Plants were treated post-emergence with an herbicide at the stage four leaves. The sprayer was equipped with GPS-RTK as guidance system and the boom width was 16m (Figure 1). The sprayer characteristics were: nozzle=110°, boom height=16cm, spray band=45cm for the full herbicide treatment and nozzle=40°, boom height=27,5cm and spray band=20cm for the localized treatment. The results of this first year of experimentation show that localized treatment and full treatment have much lower infestations than the untreated reference. On the crop row, the infestations of the "localized treatment" and "full treatment" modalities are similar, which shows that on the crop row the localized treatment is as effective as a full treatment. On the inter-row, the modality " herbicide treatment on the row then hoeing" is slightly more infested in weeds than the inter-row of the modality "full treatment", which shows that the hoeing is slightly less satisfying than the full treatment. Nevertheless, when we compare the inter-row of the modality " localized treatment on the crop row and then hoeing in the inter-row" with the inter-row of the untreated reference, we notice a hoeing efficiency that is not negligible. In the modality "full treatment", we observe that the crop row is slightly dirtier than the interrow one can possibly interpret that by an umbrella effect of the rapeseed crop during the 195 treatment. In the untreated reference, we observe that the crop row is less dirty than the interrow; this is probably due to a competitive effect of rapeseed on weeds on the row. Thus, the results of modality "localized treatment on the row then hoeing" on oilseed rape crop are encouraging. The localized treatment area with no hoeing also shows that the treatment on the crop row is not enough to have a good efficiency overall surface and that hoeing is important. That is the complementarity of chemical weeding and mechanical weeding which makes it possible to obtain the 80% efficiency observed. Figure 1: Specific spraying equipment and spraying formula used for the PLEVOP project A Decision Support Tool for localized spraying A single conventional sprayer with a large spray boom (16 m) was used for both "full treatment" and "spot treatment" strategies. In both cases, complex calculations were made to determine exactly the amounts of herbicide and water. So we had to create a decision support tool (DST) to help farmers depending on their own spraying parameters but also to provide information about the environmental benefits of a localized spraying (Treatment Frequency Index (TFI) reduction for example). As an example, considering the spray parameters described previously for both treatment (full and localized) and according a tractor speed of 10km/h, a nozzle output of 0.65l/min and using an herbicide product (2litre/ha) the results of calculation are deduced from the decision support tool. They indicate that: for the "full treatment", 86.7litre of water and 2litre of herbicide are required for a field of one hectare whereas as for the treatment on the row strategy, with a spray band of 20cm, only 0.89litre of herbicide and 86.7litre of water are required for a field of one hectare. Conclusions and Future Outlook We have tested in rapeseed crop, the use of a single conventional sprayer with a spray boom of 16m for a full and localized herbicide treatment thanks to a GPS-RKT type guidance system. The "full treatment" and "localized treatment" modalities were compared to the reference "no treatment". Results were encouraging, demonstrating that "localized treatment on the crop row then hoeing" is as efficient as "full treatment" modality. During experiences, the spraying settings had to be changed for the automatic calculations of herbicide and water quantities. The guidance system with a camera interface has to be evaluated as well. Overall, we developed a decision support tool (DST) in order to assist farmers in the volume calculations of whatever their spraying settings. Thus, environmental benefits have been added to sensitize the farmer to the positive effects of herbicide reduction. We would also like to finalize the decision support tool with an economic cost estimation. Finally, we would like to test our system on other crops (protein crops for example) and using other phytopharmaceutical products

Organisation scientifique du colloque

National audienc

Conception de Stratégies durables de gestion des Adventices dans un contexte de Changement : le projet CoSAC

International audienceLa flore adventice est nuisible pour la production agricole mais est aussi l’un des piliers de la biodiversité dans les paysages agricoles.La réduction de l'usage d'herbicides demandée par le plan ECOPHYTO, implique que la gestion des adventices dorénavant combinel'ensemble des leviers du système de culture. L'objectif du projet CoSAC était de concevoir, d’évaluer et de promouvoir des systèmesde culture conciliant réduction d'usage des herbicides, maintien de la production agricole et préservation de la biodiversité. Pourcela, il était nécessaire de : (1) mieux comprendre et prédire le fonctionnement de l'agroécosystème, notamment les mécanismesbiophysiques régissant la dynamique des communautés adventices, (2) évaluer l'effet des techniques culturales innovantes sur cetteflore, (3) développer des modèles et outils d'aide à la décision pour la conception de systèmes et leur évaluation multicritère afin dede les utiliser pour (4) proposer des stratégies durables de gestion adaptées aux contraintes (5) intégrer conseillers et agriculteurstout au long du projet pour s'assurer que les outils et innovations développés soient effectivement opérationnels.Au champ, des essais ont permis de quantifier et d'analyser les effets et la robustesse de techniques et/ou combinaisons detechniques innovantes dans différents contextes pédoclimatiques et de flores adventices. En parcelles jardinées et en serre, ils ontpermis d'analyser les processus biophysiques sous‐jacents. En effet, connaître les causes d'un effet est essentiel pour savoir dansquelles conditions et avec quelle ampleur les innovations techniques vont être efficaces. Des connaissances ont ainsi été produitespour améliorer le modèle FLORSYS qui simule la démographie, la croissance et la reproduction des adventices et des couverts cultivés.FLORSYS a servi de champ virtuel pour évaluer l'impact des adventices sur la production agricole et sur la biodiversité dans dessystèmes innovants co‐conçus. FLORSYS a aussi été adapté en un nouvel outil d'aide à la conception de systèmes de culture(DECIFLORSYS). Afin de faciliter la valorisation et le transfert des résultats, des conseillers et agriculteurs ont été impliqués à toutes lesétapes du développement des outils, de la conception et de l’évaluation des systèmes innovants, via des formations, enquêtes etateliers participatifs.AbstractWeed floras are harmful for crop production but essential for biodiversity in agricultural landscapes. The reduction in herbicide userequired by the ECOPHYTO plan implies that weed management must now rely on a judicious combination of all components of thecropping system. The objective of the CoSAC project was to design, evaluate and promote cropping systems that reconcile reducedherbicide use, crop production and biodiversity conservation. To this end, we needed to (1) better understand and predict thefunctioning of the agroecosystem, particularly the biophysical mechanisms driving weed dynamics, (2) evaluate the effects ofinnovative cropping techniques on the weed flora, (3) develop models and decision support systems for cropping system design andmulticriteria evaluation, (4) use these tools to design sustainable weed management strategies adapted for farmers' constraints, (5)integrate advisors and farmers throughout the project to ensure that the newly developed tools and innovations are operational.Field trials allowed quantifying and analysing effects and robustness of innovative cropping techniques and their combinations fordifferent pedoclimates and weed floras. Greenhouse and garden‐plot experiments allowed analysing the underlying biophysicalprocesses. Knowing the causes of effects is essential to determine in which conditions innovative practices will be efficient and howmuch. This knowledge was also used to improve the FLORSYS model which simulates the demography, growth and reproduction ofweed floras and crop canopies. FLORSYS was used as a virtual experimental field to evaluate weed impacts on crop production andbiodiversity in innovative cropping systems co‐designed with farmers. FLORSYS was also transformed into a novel tool to supportcropping‐system design (DECIFLORSYS). In order to promote and transfer the project results, advisors and farmers were implicatedduring model development as well as cropping‐system design and evaluation, via training sessions, surveys and participatoryworkshops with farmers