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  • [hal-03641550] Tracking Ideal Varieties and Cropping Techniques for Agroecological Weed Management: A Simulation-Based Study on Pea

    Pea or Pisum sativum L. is a key diversification crop, but current varieties are not very competitive against weeds. The objective was to identify, depending on the type of cropping system and weed flora, (1) the key pea parameters that drive crop production, weed control and weed contribution to biodiversity, (2) optimal combinations of pea-parameter values and crop-management techniques to maximize these goals. For this, virtual experiments were run, using FLORSYS, a mechanistic simulation model. This individual-based 3D model simulates daily crop-weed seed and plant dynamics over the years, from the cropping system and pedoclimate. Here, this model was parameterized for seven pea varieties, from experiments and literature. Moreover, ten virtual varieties were created by randomly combining variety-parameter values according to a Latin Hypercube Sampling (LHS) plan, respecting parameter ranges and correlations observed in the actual varieties. A global sensitivity analysis was run, using another LHS plan to combine pea varieties, crop rotations and management techniques in nine contrasting situations (e.g., conventional vs. organic, no-till, type of weed flora). Simulated data were analyzed with classification and regression trees (CART). We highlighted (1) Parameters that drive potential yield and competitivity against weeds (notably the ability to increase plant height and leaf area in shaded situations), depending on variety type (spring vs. winter) and cropping system. These are pointers for breeding varieties to regulate weeds by biological interactions; (2) Rules to guide farmers to choose the best pea variety, depending on the production goal and the cropping system; (3) The trade-off between increasing yield potential and minimizing yield losses due to weeds when choosing pea variety and management, especially in winter peas. The main pea-variety rules were the same for all performance goals, management strategies, and analyses scales, but further rules were useful for individual goals, strategies, and scales. Some variety features only fitted to particular systems (e.g., delayed pea emergence is only beneficial in case of herbicide-spraying and disastrous in unsprayed systems). Fewer variety rules should be compensated by more management rules. If one of the two main weed-control levers, herbicide or tillage, was eliminated, further pea-variety and/or management rules were needed.

    ano.nymous@ccsd.cnrs.fr.invalid (Nathalie Colbach) 02 Dec 2022

    https://institut-agro-dijon.hal.science/hal-03641550v1
  • [hal-03716045] Deciphering field-based evidences for crop allelopathy in weed regulation. A review

    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, allelopathy by living crops remains a contentious mechanism. A major difficulty to demonstrate the effects of allelopathy in the field is to dissociate them from those of competition. Here, we systematically and quantitatively review the literature, searching for field-based evidence of the role of allelopathy (by root exudation of living crops) in weed regulation, independently of competition, focusing on studies comparing different varieties of a given crop species. Our critical literature analysis also aims to identify weaknesses and strengths in methodology, providing insights on optimal experimental designs and avenues for future research. Our main conclusions are: (1) in most articles, the role of crop competition is disregarded or not exhaustively studied. Consequently, contrary to authors' conclusions, it cannot be determined whether weed regulation is due to allelopathy and/or to competition. (2) Few articles provided convincing evidence of the presence/absence of allelopathy in the field. (3) To further investigate allelopathy in the field we recommend to (i) finely characterize crop competition by measuring traits in the field, (ii) assess crop allelopathic potential with complementary experiments in controlled conditions or by quantifying allelochemicals in the field, and (iii) quantify the contribution of each studied trait/mechanism in explaining weed regulation in the field with multiple regression models. In conclusion, the consistent use of the suggested guidelines, as well as alternative approaches (e.g., creation of varieties with deactivated allelopathic functions, development of process-based simulation models), may provide a basis for quantifying the role of allelopathy in the field and, subsequently, for designing weed management strategies promoting weed biological regulation.

    ano.nymous@ccsd.cnrs.fr.invalid (Inès Mahé) 07 Jul 2022

    https://hal.inrae.fr/hal-03716045v1
  • [hal-04023741] Impact de la conduite des cultures intermédiaires sur la flore adventice : résultats de l’analyse de 31 essais

    Les données de 31 essais ont été analysées afin de quantifier l’impact des cultures intermédiaires sur les adventices pendant l’interculture. Les résultats montrent une très grande variabilité de la densité d’adventices à la destruction du couvert, principalement selon l’effet site (pédoclimat, précédent cultural, parcelle, etc.). La biomasse aérienne du couvert n’a pas d’effet sur la densité d’adventices (nombre d’adventices/m²). En revanche, la biomasse aérienne d’adventices (t/ha de matière sèche) décroit avec la biomasse aérienne du couvert. Il existe des différences notoires entre espèces de couvert, selon leur production de biomasse, leur vitesse de couverture du sol et les caractéristiques de leurs parties aériennes. Les couverts à forte biomasse et forte vitesse de couverture du sol limitent nettement la biomasse des adventices sans pour autant les faire disparaître. La densité d’adventices observée dans la culture suivante n’est ni corrélée à la densité d’adventices pendant l’interculture, ni à la biomasse du couvert Abstract Data of 31 field trials were analysed to quantify the impact of cover crops grown during summer fallow on weeds during this period. Results show that weed abundance at the date of cover-crop destruction greatly varies between experimental locations which differed in terms of pedoclimate, previous crop etc. Cover-crop above-ground biomass did not impact weed plant density. However, weed above-ground biomass decreased with increasing cover-crop biomass. Cover-crop species greatly differed in their ability to reduce weed biomass, according to their own biomass, their speed of soil coverage at early stages and their above-ground plant morphology. Cover crops with high levels of biomass and rapid soil coverage strongly reduced weed biomass but without eliminating weeds entirely. Weeds density monitored in crops following the cover crops were neither correlated to weeds abundance during the fallow period nor to cover crop biomass

    ano.nymous@ccsd.cnrs.fr.invalid (Pierre Villefourceix-Gimenez,) 10 Mar 2023

    https://hal.inrae.fr/hal-04023741v1
  • [hal-04031706] Are No-Till Herbicide-Free Systems Possible? A Simulation Study

    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 farming practices on 395 arable cropping systems mainly from France, and simulated them over 30 years and with 10 weather repetitions, using FLORSYS. This process-based model simulates daily multi-species weed floras and crop canopies from cropping systems and pedoclimate over the years. Three series were simulated, (1) using the recorded systems, (2) eliminating tillage without any other changes, (3) eliminating herbicides without any other changes. Each series was run twice, once with a regional weed-flora pool to simulate weed dynamics and their impact on crop production and biodiversity, and once without weeds to predict potential crop yield. Among the recorded systems, herbicide treatment frequency index (HTFI) averaged over rotation increased when tillage frequency decreased. No recorded no-till system was herbicide-free. The untilled crops with the lowest HTFI (0.16) were unusual crops, i.e., relay grass-crops or multi-annual crops. Simulations of the recorded systems showed no correlation between tillage-frequency, and weed biomass or weed-caused yield loss. When tillage was deleted without any other change, yield loss almost doubled. We identified (1) which weed species and traits (e.g., spring annuals) increased after tillage suppression and in which cropping systems, (2) which recorded systems were robust to tillage suppression in terms of yield loss (with cover crops, summer crops, etc.), (3) which no-till systems (recorded or obtained after deleting tillage) limited yield loss (e.g., with frequent and/or efficient herbicides), (4) which management techniques were associated with a reduction in tillage, in herbicides, and in yield loss (long and diverse rotations, cover crops, etc.). No tested system achieved all three objectives simultaneously. The simulations indicated that two CA pillars (diverse crop rotations, cover cropping) were essential to manage weeds while reducing (or eliminating) both tillage and herbicide use. More no-till cropping systems must be investigated to determine whether sustainable no-till herbicide-free systems are possible.

    ano.nymous@ccsd.cnrs.fr.invalid (Nathalie Colbach) 16 Mar 2023

    https://hal.inrae.fr/hal-04031706v1
  • [hal-03634508] Morphological response of weed and crop species to nitrogen stress in interaction with shading

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    ano.nymous@ccsd.cnrs.fr.invalid (Laurène Perthame) 07 Apr 2022

    https://hal.science/hal-03634508v1
  • [hal-03910768] Water limitation affects weed competitive ability for light. A demonstration using a model‐based approach combined with an automated watering platform

    Climate change is driving the need to investigate responses to water limitation of morphological traits involved in competition for light, the main resource for which crops and weeds compete in conventional temperature and tropical cropping systems, to better understand field crop-weed dynamics. Our objective was to develop an innovative approach to quantify weed species responses to water limitation, using three species. This approach combined (1) key morphological traits involved in competition for light (taken from a mechanistic crop-weed model) as criteria to analyse responses to water limitation and (2) a pot/greenhouse platform allowing automated precision-watering and daily quantification of soil water availability in each pot. For all species and growth stages, increased plant height per unit of aboveground biomass and production of smaller/thicker leaves were the most noteable responses. Plants with a strong increase in plant height per unit of aboveground biomass in response to water limitation maintained high levels of specific leaf area, even at low soil water availability. Increases in biomass allocation to roots (vs. aboveground parts) and leaves (vs. stems and reproductive organs) were also observed, but not for all species and growth stages. Overall, these effects of water limitation on morphological traits indicate strong interactions between competition for light and water.

    ano.nymous@ccsd.cnrs.fr.invalid (Delphine Moreau) 14 Jun 2023

    https://hal.inrae.fr/hal-03910768v1

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Photos de livres par Patrick Tomasso

Tracking ideal varieties for agroecological weed management in organic wheat

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Publié dans European Journal of Agronomy et écrit par P. Lebreton et al. L'objectif de la présente étude était d'effectuer des simulations avec le modèle FLORSYS afin d'identifier des paramètres intrinsèques à la variété ainsi que des idéotypes de blé pour maximiser le rendement, la tolérance aux adventices et la suppression des adventices.

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FlorSys et ses dérivés en vidéo

Date de modification : 19 juin 2025 | Date de création : 28 février 2023 | Rédaction : Jean Villerd