DS0501 - Productions durables

Designing sustainable weed management strategies in a changing context (climate, agricultural practices, biodiversity) – CoSAC

CoSAC

Basis and Rationale of the project <br />Toward a reduction of herbicide use, maintaining agricultural production and biodiversity conservation, all in a context of permanent global change <br /> <br />

Overall objectives and scientific /technical obstacles of COSAC project

Reduced herbicide use required by French and European legislation will change weed management. Weeds are very harmful for crop production but contribute to biodiversity in agricultural landscapes. Consequently, reduced herbicide use, agricultural production and biodiversity conservation must be reconciled in arable crops. The project team consists of multidisciplinary partners (ecologists, agronomists, modellers,...) from research and development in order to: (1) understand and quantify with experiments the effects of novel agricultural practices on weed flora and on the functioning of the agroecosystem, (2) design tools predicting the effects of agricultural practices and pedoclimate on weed flora, (3) use these tools to design weed management strategies and to evaluate their performance in various contexts of changing agricultural practices, climate and biodiversity, (4) facilitate the adoption of the novel weed management strategies by farmers.

Task 1 will focus on crop diversification, localized technologies and no till. These techniques will be monitored in field experiments, the underlying processes will be studied in controlled conditions and in fields.
Task 2 will use these results to improve the existing FLORSYS model which quantifies the effects of cropping system and pedoclimate on weed dynamics and calculates indicators of weed harmfulness and benefits. FLORSYS will be further improved by adding herbicide resistance and seed dispersal functions, by upscaling from the field to a multi-field mosaic. FLORSYS will be used to run sensitivity analyses to identify correlations between cultural techniques and weed species traits. These simulations will also be used to develop a decision-aid tool for evaluating cropping systems in terms of weed harmfulness and benefits, after questioning future users to identify pertinent evaluation criteria and model uses. If possible, we will develop a further tool that propose cropping systems answering to the user's objectives.
Task 3 will use FLORSYS and its tool progeny to evaluate existing cropping systems identified in past farm surveys, existing farm networks and cropping system trials. New cropping systems reconciling reduced herbicide use, agricultural production and biodiversity conservation will be designed by experts, and evaluated with FLORSYS and its progeny. Existing and prospective cropping systems will then be improved in a second loop based on their simulated performance Then, the sensitivity of the best strategies to different changes will be tested. To take account of farmers' objectives and constraints during cropping system design, farmer interviews will be organized to identify obstacles that hinder the adoption of technical innovations.
Task 4 will organize the publication and dissemination of the project results, via meetings, website, training sessions on the newly developed tools and weed management strategies for advisors and farmers.

The expected results are:
1. Identification and quantification of the effects of innovative techniques (spatialisation of techniques, diversification of crop canopies and rotations, no till) on weed flora;
2. A better understanding of weed characteristics and biophysical mechanisms involved in responses to agricultural practices;
3. A complex «virtual field« model quantifying the effects of cultural techniques and pedoclimate on the biological cycle of weeds, which is used to perform virtual experiments in a wide range of climatic and soil and plant environments;
4. Simple tools to assess and design cropping systems, based on the «virtual field model«;
5. Design methodologies of cropping systems, combining diagnostic of existing agricultural situations, workshops of innovative strategies design and assessment by experts using the «virtual field« model and other multi-criteria assessment tools of sustainability;
6. Weed management strategies reconciling agricultural production, reduction of input use and biodiversity;
7. A better understanding and consideration of obstacles to the adoption of innovations proposed by researchers and advisers;
8. Wide dissemination of results (knowledge, methods, tools, management strategies) to researchers, students, advisers and farmers, through teaching modules, training, conferences, technical articles, websites etc;
9. Eventually, commercial solutions based on the localized weeding robot and image analysis methods for the detection and identification of weeds.

CoSAC aims to better manage and use agroecosystem services by maintaining optimum production levels. It focuses on the management of weeds, which are a major pest in farming systems, but also a source of biodiversity in agricultural landscapes and are an important trophic resource for animal biodiversity in arable crops. The latter provide the bulk of food production in Europe and also contribute to the production of green energy.
The main objective of the proposed work is the design of weed management strategies mobilizing innovative combinations of practices by combining pest control, reduced pesticide use, maintenance of production levels, and preserving biodiversity and services rendered by weeds. The performance of these innovative strategies, particularly their sustainability, will be evaluated with a multi-criteria approach.
To a lesser extent, the project also contributes to the challenge «sober resource management and adaptation to climate change« by (1) proposing efficient agricultural systems in terms of input use (herbicides, inorganic nitrogen ...), (2) improving our knowledge of the agroecosystem functioning at different temporal and landscape scales to predict the performance of different management scenarios, and by (3) exploring the impact of different climate change scenarios on weed management.
The expected benefits for society reflect the issues addressed by the project in terms of impact of weed management practices, especially in the agricultural world. More generally, this project will develop alternative agricultural systems that minimize the environmental and health impacts and maximize services.

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Reduced herbicide use required by French and European legislation will change weed management. Weeds are very harmful for crop production but contribute to biodiversity in agricultural landscapes. Consequently, reduced herbicide use, agricultural production and biodiversity conservation must be reconciled in arable crops. The project team consists of multidisciplinary partners (ecologists, agronomists, modellers,...) from research and development in order to: (1) understand and quantify with experiments the effects of novel agricultural practices on weed flora and on the functioning of the agroecosystem, (2) design tools predicting the effects of agricultural practices and pedoclimate on weed flora, (3) use these tools to design weed management strategies and to evaluate their performance in various contexts of changing agricultural practices, climate and biodiversity, (4) facilitate the adoption of the novel weed management strategies by farmers.
Task 1 will focus on crop diversification (cover crops, crop associations), localized technology (local herbicide spraying, fertilizer placement in crop rows, strip-till) and no till. These techniques will be monitored in field experiments, the underlying processes will be studied in controlled conditions (competition for light, nitrogen and water; root architecture; seed germination on soil surface...) and in fields (weed detection and identification by aerial image analysis; soil structure and hydrothermal conditions in no-till).
Task 2 will use these results to improve the existing FLORSYS model which quantifies the effects of cropping system and pedoclimate on weed dynamics and calculates indicators of weed harmfulness (e.g. crop yield loss) and benefits (e.g. species richness, food offer for bees). FLORSYS will be further improved by adding herbicide resistance and seed dispersal functions, by upscaling from the field to a multi-field mosaic, by improving the phenology prediction, and by completing the weed evaluation indicators. FLORSYS will be used to run sensitivity analyses to identify correlations between cultural techniques and weed species traits. These simulations will also be used to develop a decision-aid tool for evaluating cropping systems in terms of weed harmfulness and benefits, after questioning future users (scientists, advisors, farmers) to identify pertinent evaluation criteria and model uses. If possible, another tool for designing cropping systems as a function of the user's goals in terms of weed harmfulness and benefits will be developed.
Task 3 will use FLORSYS and its tool progeny to evaluate existing cropping systems identified in past farm surveys, existing farm networks (DEPHY) and cropping system trials (INRA, ARVALIS, SYPPRE project). New cropping systems reconciling reduced herbicide use, agricultural production and biodiversity conservation will be designed by experts (scientists, advisors), and evaluated with FLORSYS and its progeny. Existing and prospective cropping systems will then be improved in a second loop based on their simulated performance in a second loop of conception. Then, the sensitivity of the best strategies to different changes (regulations, socio-technical context, climate, weed flora) will be tested. The best systems will be evaluated by multicriteria analysis (DEXIiPM® and SYSTERRE®) for their economic, environmental and organisational performances. To take account of farmers' objectives and constraints during cropping system design, farmer interviews will be organized to identify obstacles that hinder the adoption of technical innovations.
Task 4 will organize the publication and dissemination of the project results, via meetings, website, training sessions on the newly developed tools and weed management strategies for advisors and farmers.

Project coordinator

Madame Nathalie Colbach (INRA UMR1347 Agroécologie - AgroSup Dijon - UB)

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.

Partner

ARVALIS ARVALIS - Institut du végétal
INRA Agroécologie INRA UMR1347 Agroécologie - AgroSup Dijon - UB
INRA EcoInnov INRA UAR1240 EcoInnov
ACTA le réseau des filières animales et végétales
CETIOM CENTRE TECHNIQUE INTERPROFESSIONNEL DES OLEAGINEUX ET DU CHANVRE
INRA PSH INRA Unité Plantes et Systèmes de culture Horticoles
INRA LAE INRA UMR1132 Université Lorraine-INRA Agronomie et Environnement Nancy-Colmar

Help of the ANR 498,985 euros
Beginning and duration of the scientific project: September 2014 - 48 Months

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