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Balancing Profitability, Protein production, and Pesticide reduction: what are the levers for action for French arable farms?
No full textNational audienceBased on a panel of 458 arable farms observed over 27 years in an agricultural French region (the Meuse district), we evaluate the implications of three contrasting strategies: maximizing profitability, enhancing protein supply, and reducing pesticide use. We apply a farm activity model to assess the impacts of these strategies on margin, focusing on cost savings and revenue increases through yield/pricing adjustments. These impacts are measured by first comparing the optimal situation to the observed situation within each strategy, thereby identifying potential pathways for improvement. Subsequently, we compare the three optimal scenarios along the efficiency frontier to evaluate the potential opportunity costs for farmers when selecting a specific strategy relative to the profitability maximization strategy, which serves as the reference. This analysis indicates that the opportunity cost associated with maximizing protein supply is relatively higher than that of reducing pesticide use. This finding suggests that policiesaimed at decreasing pesticide use could be economically feasible, offering fewer financial drawbacks and clearly enhanced environmental benefits, compared to strategies that focus on increasing protein production
Combining a field experiment and literature to model the regrowth probability of perennial storage organs fragmented by tillage: Case study of Cirsium arvense (L.) Scop
No full textInternational audienceManagement of perennial weeds has become increasingly difficult with the reduction of herbicide use. Creeping perennials accumulate reserves in specialized belowground organs from which they regenerate new plants after a disturbance. Through tool selection, tillage operations could be optimized to reduce perennial-weed reserves and limit regeneration. In the present study, the effect of five tools on the fragmentation of the creeping roots of Cirsium arvense (L.) Scop. (Canada thistle), a major perennial weed in arable crops, were analysed. A field trial was set up to measure the lengths of the root fragments left after tillage. Five tools were tested: mouldboard ploughing, rotary harrow, disc harrow, rigid-tine cultivator and goose-foot cultivator. Fragment-length distribution varied according to the tool: rotary harrow left the smallest (3.7 cm on average) and least variable fragment lengths, mouldboard ploughing the longest (12.7 cm) and most variable ones. The other tools produced intermediate-sized fragments (8–10 cm). Based on these results and literature, a model was proposed to predict perennial-weed regeneration probability from storage-organ fragments after one tillage run. The effects of six factors, which were agronomic (tillage tool), environmental (soil conditions and temperature) and biological (storage-organ fragment diameter, maximal belowground-shoot length and pre-tillage storage-organ distribution), were tested through a sensitivity analysis. According to the model, the probability of fragment regeneration success is lower for the rotary harrow than for the mouldboard plough. The most important drivers of fragment regeneration success were the biological traits: fragment diameter and maximal belowground-shoot length per unit fragment biomass. The present model should be complemented to predict the effect of tillage on perennial-weed regrowth and help improving non-chemical weed-management strategies. To achieve this, further research is needed on plant regrowth potential from storage organs and their architecture in the soil
Crop management strategy redesign enables a reduction in reliance on pesticides: A diachronic approach based on a diversity of French commercial farms
No full textInternational audiencePesticides are widely used in agriculture to manage pests, weeds and diseases with consequences on ecosystem and human health. Reducing pesticide reliance appears as a necessary step for transitioning to sustainable farming systems. Many non-chemical techniques to control pests, weeds and diseases are individually well documented, but quantitative assessment of how much the reliance on pesticides could be decreased through a holistic approach of cropping system re-design combining several individual techniques was lacking. A diachronic approach was conducted on 913 French commercial farms from the DEPHY network, spanning a diversity of contexts and management strategies. Regression Trees and Random Forest models were run to identify combinations of changes in management strategies associated with the evolution of pesticides reliance over time, in a range of production contexts. The consequences of these changes on pesticide-related risks to human health and the environment were also investigated. Farm reliance on pesticides and pesticide-related risks to human health and the environment were reduced in 65.7% and 60.3% of the farms, respectively. The greatest reductions in pesticide reliance were observed in farms with the highest initial levels of reliance on pesticides. Crop diversification and reduced nitrogen fertilization were often associated with reduced pesticide reliance. This study highlights the value of real farm networks for identifying and promoting combinations of techniques that help reduce pesticide dependency and move towards more sustainable farming systems
How have atmospheric components of the local water cycle changed around the abrupt climatic shift over France?
No full textInternational audienceThe significant increase in surface air temperature experienced by Western Europe over the last few decades has resulted in an abrupt warming in France, around 1987/1988 years. This climatic shift impacted hydrological cycle, particularly by reducing runoff in spring and summer. Evapotranspiration and precipitation have been identified as the main drivers of climatic water balance. But the impact of the 1987/1988 climatic shift on local water cycle over France has not been quantified yet. This study tries to assess the consequences of this rapid warming on the main climatic components of local water cycle. Climate variables linked to the water cycle extracted from a reanalysed observed climate database are analysed using robust Bayesian change points detection and mean comparison techniques. After the abrupt rise in surface air temperature and surface solar radiation, water demand increases significantly on almost the entire French territory in spring, summer and autumn. Our results show that, from March to May, the vegetation cover is able to respond to this increase by drawing from the soil water reservoirs. But in summer, most of the territory is facing a significant rise in water constraint (i.e. difference between potential and actual evapotranspiration), extending on the last decade over autumn. In spring and summer, the increase in potential evapotranspiration is the main driver of the intensification of water constraint. In the beginning of autumn, longer dry spell also plays a major role in the lengthening of periods of water constraint. This innovative study highlights the specific impact of a climatic shift on the main components of the atmospheric water balance at regional and local scale. As the observed changes in climate hazard linked to water cycle affect growth cycle of the majority of the vegetation covers and crops, this could lead to a worsening of hydric stress events. As such climatic shifts are expected to happen again in the future, their impacts on the local water cycle represent a major issue for natural terrestrial ecosystems as well as for agriculture
Construire des filières territorialisées : les certifications comme rouage clef du commoning
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Transcriptomics and metabolomics to characterize and identify fungal metabolites phytotoxic to Phelipanche ramosa, a parasitic plant of crops
No full textNational audienceBranched broomrape (Phelipanche ramosa (L.) Pomel), an holoparasitic root weed with a widehost range, is known for its devasting effects on many crops worldwide. Soil fungi, notablyFusarium sp. are described as pathogenic to broomrape with the hypothesis of the productionof phytotoxic fungal metabolites. The framework of my project is the search for phytotoxicfungal metabolites for P. ramosa using four Fusarium sp. strains, isolated from symptomaticbranched broomrapes and identified as a promising candidate for P. ramosa biocontrol. For thispurpose, a multi-omics approach combining genomics, transcriptomics and metabolomics isused and will i) provide a more detailed understanding of the molecular and biochemicalmechanisms involved in the interaction between pathogenic fungi and P. ramosa ii) enable theidentification of functional clusters with a pangenomic approach by the comparison of fungalgenomes iii) determine if these metabolites are constitutively expressed in response to the hostplant exudates. In this presentation I presents you a part of my work, recently submitted, thatinvestigated fungal metabolites phytotoxic for P. ramosa and produced by the F. venenatumMIAE02836 strain. The methodology developed combined quantification of necrosis onbroomrape microcalli by image analysis and characterization of potential phytotoxins byuntargeted metabolomics. Phytotoxicity tests of crude extracts from the fungus alone or inpresence of broomrape on P. ramosa microcalli and quantification of necrosis by image analysisconfirmed the phytotoxic potential of F. venenatum MIAE02836 metabolites towards the earlydevelopmental stages of P. ramosa. Untargeted metabolomics data analysis revealed numerousmetabolites produced by the strain of which four metabolites, accumulated in presence with theparasitic plant, are known for their phytotoxic potential: maculosin, cyclo(Leu-Phe),phenylalanyl-D-histidine and anguidine. These results suggest that combining imageacquisition of the microcalli screening test and untargeted metabolomics is a relevant methodto characterize fungal phytotoxins and opens up interesting prospects for the use of these laterto control P. ramosa
Impact of drought on crop weather insurance loss ratio in France in a context of recent global warming
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First report of Fusarium oxysporum causing damping‐off on Datura stramonium in France
No full textInternational audienceDatura stramonium (jimsonweed, thorn apple) is a toxic, invasive weed of summer crops. It contaminates grains during harvest, causing health problems (Perharič et al., 2013; Mutebi et al., 2022). In July 2022, in a maize plot near Toulouse (France), c. 36 plants of D. stramonium per m2 were counted. One to two plants with crown shrinkage symptoms were detected every 10 m2 (Fig. 1). Fifteen diseased plants were collected. The stem base of each plant was surface disinfected, cut into pieces, and plated on malt extract agar. Fusarium oxysporum-like colonies grown from these fragments were purified by single-spore sub-culturing and preserved in the Microorganisms of Interest for Agriculture and Environment (MIAE) collection (INRAE Dijon, France). Colonies transferred onto potato dextrose agar for macroscopic observations exhibited white aerial mycelium, becoming progressively pink (Fig. 2). Microscopic examination of cultures on carnation leaf agar revealed oval single-celled microconidia and multicellular spindle-shaped macroconidia characteristic of F. oxysporum (Fig. 3; Nelson et al., 1983)