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Le Chenin : origines, caractéristiques et variations
No full textActes de la conférence donnée au Congrès International du Chenin Blanc le 12 June 2025 à Angers.International audienceDuring this introductory lecture, I will present a monograph of the Chenin grape variety that will review the current ampelographic knowledge of this variety and address the following aspects: origin and homonymy, botanical characteristics, agronomic value (phenology, physiology, adaptation to different terroirs, rootstocks, susceptibility to diseases and pests), technological value, intra-varietal diversity, clones and perspectives of varietal improvement.Au cours de cette conférence introductive, je présenterai une monographie du cépage Chenin qui permettra de faire le point sur les connaissances ampélographiques actuelles de cette variété et qui abordera les aspects suivants : origine et homonymie, caractéristiques botaniques, valeur agronomique (phénologie, physiologie, adaptation aux différents terroirs, porte-greffes, sensibilité aux maladies et ravageurs), valeur technologique, diversité intra-variétale, clones et perspectives d’amélioration variétale
Meta-modeling of a physically-based pesticide runoff model with a Long-Short term Memory approach
No full textInternational audienceSurface water contamination by pesticides is widespread across the European Union (European Environment Agency, 2024). A primary pathway for pesticide transfer from agricultural fields to surface waters is surface runoff (Wauchope et al., 1995 [https://doi.org/10.1162/neco.1997.9.8.1735]; Louchart et al., 2001 [https://doi.org/10.2134/jeq2001.303982x]; Reichenberger et al., 2007 [https://doi.org/10.1016/j.scitotenv.2007.04.046]). This process is influenced by various spatial and temporal factors, including compound properties, topography, application date and methods, climate, soil properties, and agricultural practices (Shipitalo and Owens, 2003 [https://doi.org/doi: 10.1021/es020870b]). Richards-based models are valuable for predicting the temporal variability of pesticide runoff (Métayer et al., 2024 [https://doi.org/10.1016/j.scitotenv.2023.167357]), especially in regions with high rainfall intensity variability, such as the Mediterranean. However, their operational application is constrained by substantial computational demands and extensive data requirements. Meta-modeling approaches provide a means to reduce the computational time of an initial physically-based model. Among these, the Long Short-Term Memory (LSTM; Hochreiter and Schmidhuber, 1997 [https://doi.org/10.1162/neco.1997.9.8.1735]) model has demonstrated high efficiency in replicating hydrological (Kratzert et al., 2018 [https://doi.org/10.5194/hess-22-6005-2018]) and hydrochemical time series (Pyo et al., 2023 [https://doi.org/10.1016/j.wroa.2023.100207]), making them a promising meta-modeling strategy for pesticide runoff models. This study aimed to develop and evaluate a meta-modeling approach using LSTM models for a Richards-based model to simulate hourly variations in water and pesticide runoff over an entire year while minimizing computation times. The proposed approach was applied to a field-scale pesticide runoff model implemented in the fully spatially distributed hydrological model MHYDAS-Pesticide 1.0 (Crevoisier et al., 2021 [https://hal.inrae.fr/hal-04090048v1]) that integrates Richards and convection-dispersion equations, the uniform mixing cell concept, and an overland flow routine. This represents a challenge for at least the following three reasons: i) the time series contains mainly zero values of runoff discharge, ii) the prediction of pesticide runoff requires an efficient prediction of water runoff and ii) the order of magnitude of the targeted non-zero values of runoff concentration varies by several orders of magnitude. The LSTM meta-model was trained and validated using 560,560 annual time series simulations generated by the initial physically-based model. The training dataset comprised 70% of the simulations, with the remaining 30% reserved for validation. The resulting meta-model accounted for meteorological conditions, compound properties, and pesticide application date and rate. It demonstrated high accuracy in simulating hourly runoff and pesticide concentrations, achieving significant reductions in computation time. However, challenges remain, such as improving the precision of runoff occurrence simulation and enhancing the meta-model's generalizability by incorporating additional static parameters as inputs. The poster will focus on the methodology for the meta-model’s development and the results of its evaluation. The meta-model has been implemented within a fully spatially distributed physically-based hydrological model, MHYDAS Pesticide, to form an hybrid version
Wheat crop models underestimate drought stress in semi-arid and Mediterranean environments
No full textInternational audienceUnder climate change and increasingly extreme weather, projections of water demand and drought stress from process-based crop models can inform risk management and adaptation strategies. Previous studies investigating maize crop models demonstrated considerable error in the simulation of water use, and no similar evaluation of wheat crop models exists. The aims of this study were to (1) evaluate wheat crop models’ performance in reproducing observed daily evapotranspiration (ET) for Mediterranean and semi-arid environments, and (2) identify factors and processes associated with model error and uncertainty. These were assessed with an ensemble of wheat crop models for two experiments, one conducted in Bushland, Texas, USA (three seasons, deficit and full irrigation) and another in Avignon, France (four rainfed seasons) with winter bread and durum wheat, respectively. Models were calibrated with all observed data for crop growth. The model ensemble median underestimated water use in all environments evaluated, suggesting a systematic bias. The relative error in underestimating daily ET was constant across levels of atmospheric evaporative demand; therefore, the absolute error was greater for days with larger evaporative demand. This implies errors in the soil water balance increase more rapidly under high evaporative demand conditions. Using a potential versus reference crop evapotranspiration approach did not explain relative model performance. However, the sensitivity analysis indicated that simulation of atmospheric evaporative demand terms explained much more uncertainty in seasonal water use than terms related to soil depth or root growth. Errors in simulated leaf area index were associated with errors in daily simulated ET, but the relationship varied with the growth stage. Collectively, the results suggest the need to improve simulation of atmospheric ET demand to avoid underestimating projected impacts of drought or required water resource availability for viable production systems
Crop diversity trends captured by Indigenous and local knowledge: introduction to the symposium
No full textSymposium/Special IssueInternational audienc
Comprendre la fabrique de l’utilisabilité des indicateurs de biodiversité. Le cas des dendromicrohabitats
No full textInternational audienceBiodiversity indicators are generally quantitative measures used to summarise, illustrate and communicate complex phenomena relating to biodiversity in a simple way. An increasing number of biodiversity indicators have been recently developed to address different aspects of biodiversity, but their use is very uneven. This article examines the usability criteria for biodiversity indicators, where usability is understood as the assessment by stakeholders of the potential of these indicators to be taken into account in public decision-making and management processes, using the case of a forest biodiversity indicator, namely tree-related microhabitats. We have applied a now classic usability analysis framework to this case study, with a twofold objective: firstly, to understand the usability of this indicator; and secondly, to examine the capacity of the chosen analysis framework to account for it. Interviews with producers and users of the tree-related microhabitats indicator revealed that the usability criteria used in this analysis framework –credibility, relevance, legitimacy and feasibility– do play a role in the usability of tree-related microhabitats. However, they do not take into account important elements mentioned by the informants. In order to address these limitations, we propose two modifications to the usability criteria. Firstly, we suggest extending the legitimacy criterion to encompass dimensions pertaining to the substantial legitimacy of the indicator. Secondly, we propose incorporating the sensitive, aesthetic and moral dimensions of the indicator, which emerged as a central element of its feasibility for our informants. Our findings therefore lead us to recommend an approach to the usability of biodiversity indicators that attends to their sensitive, aesthetic and ethical dimensions. They also suggest that the usability of an indicator is not absolute but relative, and is embedded within a dynamic system of indicators.Les indicateurs de biodiversité sont des mesures, généralement quantitatives, utilisées pour synthétiser, illustrer et communiquer de manière simple des phénomènes complexes relatifs à la biodiversité. Cet article réfléchit aux critères d’utilisabilité des indicateurs de biodiversité, l’utilisabilité étant entendue comme l’évaluation par les acteurs de leur potentiel à être pris en compte dans les processus de décision publique et de gestion, à partir du cas d’un indicateur de biodiversité forestière, les dendromicrohabitats. Il applique à ce cas d’étude un cadre d’analyse de l’utilisabilité aujourd’hui classique, dans un double objectif : comprendre l’utilisabilité de cet indicateur et discuter les critères retenus par ce cadre d’analyse pour en rendre compte. Nous nous appuyons sur une enquête qualitative auprès de chercheurs qui ont contribué à la construction de l’indicateur dendromicrohabitats, de gestionnaires et de décideurs qui l’utilisent. Nous montrons que les critères d’utilisabilité mobilisés dans ce cadre d’analyse – la crédibilité, la pertinence, la légitimité et la faisabilité – interviennent effectivement dans l’utilisabilité des dendromicrohabitats, mais ne couvrent pas tous les éléments mentionnés par nos informateurs. Nous proposons de compléter le cadre d’analyse de l’utilisabilité de deux manières : premièrement, en étendant le critère de légitimité aux dimensions renvoyant à la légitimité substantielle de l’indicateur ; deuxièmement, en prenant en compte les dimensions sensibles, esthétiques et morales de l’indicateur, apparues comme un élément central de sa faisabilité pour nos informateurs. Notre travail conduit ainsi à défendre une approche de l’utilisabilité des indicateurs de biodiversité attentive à leurs dimensions sensibles, esthétiques et éthiques. Il suggère également que l’utilisabilité d’un indicateur n’est pas absolue mais relative et s’inscrit dans un système dynamique d’indicateurs
Computational lower bounds in latent models: clustering, sparse-clustering, biclustering
No full textIn many high-dimensional problems, like sparse-PCA, planted clique, or clustering, the best known algorithms with polynomial time complexity fail to reach the statistical performance provably achievable by algorithms free of computational constraints. This observation has given rise to the conjecture of the existence, for some problems, of gaps -- so called statistical-computational gaps -- between the best possible statistical performance achievable without computational constraints, and the best performance achievable with poly-time algorithms. A powerful approach to assess the best performance achievable in poly-time is to investigate the best performance achievable by polynomials with low-degree. We build on the seminal paper of Schramm and Wein (2022) and propose a new scheme to derive lower bounds on the performance of low-degree polynomials in some latent space models. By better leveraging the latent structures, we obtain new and sharper results, with simplified proofs. We then instantiate our scheme to provide computational lower bounds for the problems of clustering, sparse clustering, and biclustering. We also prove matching upper-bounds and some additional statistical results, in order to provide a comprehensive description of the statistical-computational gaps occurring in these three problems
Les impacts des transformations agraires sur la consommation d'eau et d'énergie au sein d'un territoire : agriculture comparée et métabolisme territorial en Inde semi-aride
No full textInternational audienceCette étude documente les transformations d'une petite région agricole semiaride du plateau du Deccan en Inde des années 1950 à nos jours. La méthodologie combine les approches de l'agriculture comparée et du métabolisme territorial. Sont représentés des flux d'eau et d'énergie entre catégories sociales d'agriculteurs et d'éleveurs sur la période. Dans les années 1950, animaux de traction et hommes étaient les clés de voûte du système agraire. Depuis, d'importantes politiques agraires ont permis à de nombreuses familles d'accéder à du foncier, ont rendu possible la culture d'arachide en cycle court et ont encouragé la moto-mécanisation. La place de l'élevage de traction a été considérablement réduite, mais des formes d'élevage spécialisées comme l'élevage pastoral ovin se sont renforcées. Notre approche permet d'analyser la question environnementale comme un phénomène historiquement et socialement constitué
Impacts of soil storage on microbial parameters
No full textVoir aussi le preprint : Impacts of soil storage on microbial parameters, EGUsphere [preprint], https://doi.org/10.5194/egusphere-2024-411, 2024International audienceThis review aims to determine the impact of soil storage on microbial parameters (abundance/biomass, activity and various diversity metrics). We analysed the literature dealing with the impact of storage practices (cold, freeze, dry, freeze-dry and ambient storage) on soil microbial parameters. A total of 73 articles were included in the analysis, representing 261 basic data (impact of a given storage practice on a microbial parameter). Globally, 74 % of these data showed significant impact of storage on the measured microbial parameters, as compared to those measured on fresh, nonstored soil samples. The storage practices showed various effects on the soil microbial parameters, with sometimes opposite effects across different soil types. For instance, various soil enzyme activities did not respond the same way to storage practices, even in a given soil type. There are currently too few studies to draw recommendations, but some studies suggest that the pedoclimatic context could be useful for choosing the best storage option, with soils that regularly undergo drought or freezing being less impacted by dry and freeze storage, respectively. I conclude that storage practices for soil samples, when unavoidable, should be carefully selected according to conditions that prevail in the native soil environment, to microbial parameters that are analysed (even though there is no consensus for a best practice), and with different storage practices for different microbial parameters if necessary
Questionner la liberté d’installation des médecins : un éclairage sociologique
No full textNational audienc
Estimación de la condición corporal de vacas mestizas doble propósito (Bos taurus × Bos indicus), en Cuba: propuesta de un nuevo sistema y escala de notación
No full textInternational audienceThe body condition (BC) score assessment of a given animal, reflects of the feeding and nutrition quality, is a key indicator for monitoring the body reserves status. Despite its subjective nature, the Body Condition Score (BCS) remains the most cost-effective and widely used method in animal science to estimate BC due to its simplicity and ease of adoption. However, most of the BCS grids used in tropical regions are adapted from systems developed for temperate breeds, which differ in morphological and anatomical traits and then limits stakeholders’ adoption, accuracy and applicability. Aim: Analyze and validate a novel BCS system for Cuban cattle, proposing a six-point scale (i.e., from very emaciated –0– to overweighed –5– BC) adapted to current commercial dairy genotypes (product of deliberate Bos taurus × Bos indicus crossbreeds). Materials and methods: Ad hoc pictures of individual cows representing several BCS levels were taken at commercial farms in Camagüey (21°N-77°W) from two angles –right and back views– to develop the grid, which was then validated with around twenty local stakeholders. Weighted kappa coefficients (κw) were performed to assess inter-assessor agreement. Results: A BCS system was proposed for dual-purpose crossbred cows, adapted to current commercial genotypes, which was accepted by the evaluators and considered simple and useful. The Weighted Quadratic Kappa coefficient was excellent (κw= 0.84-0.842). Conclusions: The proposed BCS system is relatively simple, and may facilitate the applicability and adoption of regular, accurate BCS assessment by adequately trained operators linked to animal production environments in Cuba.La condición corporal (CC) de un animal, reflejo de la calidad de la dieta, es un indicador pertinente para monitorear sus reservas corporales. Aunque subjetivo, la nota de estado corporal (NEC; Body Condition Score – BCS – en inglés), es el método más barato, convencional y de fácil aplicación utilizado en zootecnia para estimar la CC; sin embargo, las escalas empleadas en los trópicos han sido importadas de sistemas con razas templadas, en su mayoría con rasgos morfológicos diferentes, lo que limita la adopción y precisión. Objetivo. proponer y validar un sistema NEC para vacas mestizas doble propósito (Bos taurus × Bos indicus), con una escala adaptada a los genotipos comerciales actuales cubanos. Materiales y métodos: Se tomaron fotos de individuos representantes en siete fincas de la provincia de Camagüey (21°N-77°O), a 3 m de distancia y desde dos ángulos –flanco derecho y trasero–. Estas sirvieron de base para construir la escala (dibujos originales comentados, hechos a mano), la cual fue validada con unos veinte actores locales. Se calculó el coeficiente Kappa Cuadrático Ponderado (κw) para evaluar la concordancia entre evaluadores. Resultados: Se propuso un sistema NEC para vacas mestizas doble propósito, adaptada a los genotipos comerciales actuales, que fue aceptada por los evaluadores y considerada sencilla y útil. El coeficiente Kappa Cuadrático Ponderado resultó excelente (κw= 0,84 - 0,842). Conclusión: El sistema propuesto resulta sencillo y viable para facilitar la estimación frecuente de la CC de vacas en condiciones cubanas de manera precisa, con operadores adecuadamente formados y entrenados