Search

16 pages; International audience; tUnderstanding differences in phenology for varieties of a given species is important for making informeddecisions on variety choice in the context of climate change and breeding new cultivars. Phenologicalmodels that incorporate temperature as a key environmental factor can be used to describe the differencesin phenological timing between cultivars. This paper outlines a methodology, based on a phenologicalmodel, for classifying the timing of flowering and veraison for a substantial number of varieties of thegrapevine (Vitis vinifera L.). 95 varieties were characterized for flowering and 104 varieties for veraison.Various statistical measures were used to assess the performance and predictions of the model at thevarietal level: model efficiency, root mean squared error and confidence intervals. The methodologymight be used to understand varietal differences for other species in future studies. Model outputs canbe used in combination with predicted climate change scenarios to assess the suitability of varietiesunder climate conditions of the future.

EAGESTADAGROSUPCT1EA DOCT; De l’imagerie pour caractériser la vigne. Quelles perspectives pour la profession ?

EA GESTAD Agrosup CT1; International audience; Over the last years, the literature presents new technologies to optimize vineyard management. In the proximal sensing context, optical sensors are mainly developed to characterize the vegetation and the most famous one is the Greenseeker RT-100 (Trimble, Germany), that provides NDVI. The interpretation of its measurements is complex because it overlaps quantitative and qualitative information. However, it is a robust active sensor especially dedicated to characterize vineyard at early growth stage. To overcome these limits, we developed a multispectral (RGB, NIR) imaging system. We present a first application of spectral imagery, in proximal sensing conditions, to characterize the vine foliage of three grapevine varieties (Meunier, Pinot Noir and Chardonnay) at four phenological stages. The imaging system is embedded on a ground vehicle acquiring images with natural light, and an original radiometric calibration is proposed. From images, three agronomic indices (NDVIimage, NDVIvegetation and “foliage occupation”) are defined. They are computed from entire images and from the area of the grapes. These indices are compared to Greenseeker ones at the beginning of berry formation to be assessed. Whatever the grapevine variety the NDVIimage is in agreement with the index provided by Greenseeker (NDVIGS). At the other stages, the comparison of NDVIGS to the other indices leads to a new interpretation of NDVIGS depending on the phenological stage. The new indices provide a better understanding on the part of quantitative and quantitative information in Greenseeker index and lead to a more accurate leaf quantity estimation (from entire images), or specific physiological status characterization.

International audience; The oxygenation of Champagne wine after 4 and 6 years of aging on lees in bottle was investigated by FTICR-MS and UPLC-Q-TOF-MS. Three levels of permeability were considered for the stoppers, ranging from 0.2 to 1.8 mg/L/year of oxygen transfer rate. Our results confirmed a good repeatability of ultrahigh resolution FTICR-MS, both in terms of m/z and coefficient of variation of peak intensities among biological replicates. Vintages appeared to be the most discriminated features, and metabolite annotations suggested that the oldest wines (2006) were characterized by a higher sensitivity towards oxygenation. Within each vintage, the oxygenation mechanisms appeared to be different for low and high ingresses of oxygen, in agreement with the hormesis character of wine oxygenation. In the particular case of single variety wines and for a given level of stopper permeability, our results also showed that variety discrimination could be easily achieved among wines.

absent

Ce volume regroupe les textes issus du programme Casdar "Innovation et Partenariat" et "Recherche technologique" de 2015. Il a été réalisé sous l’égide du GIS Relance Agronomique. Ce volume regroupe les textes issus du programme Casdar "Innovation et Partenariat" et "Recherche technologique" de 2015. Il a été réalisé sous l’égide du GIS Relance Agronomique.; 3500 samples of fungal flora were studied for their diversity and their potential to antagonizemycotoxinogenic flora. 45 were characterized with respect to their ability to inhibit in vitro the growth ofPenicillium expansum and Aspergillus carbonarius as well as the production of patulin and ochratoxin A.The most promising strains were tested as antagonists in organic and conventional vineyards andorchards as well as in production with varying degrees of success. Following this program, the ciderindustry has a patulin labeling method with 13C. The cytotoxicity tests carried out on ascladiol anddeoxypatulinic acid showed their absence of toxicity. Finally, the two sectors have screening methods toquickly set up additional experiments in the event of natural contamination linked to changes in climateand practices.; 3500 échantillons de flores fongiques ont été étudiés d’après leur diversité et leur potentiel antagonistevis-à-vis des flores mycotoxinogènes. 45 ont été caractérisées vis à vis leur capacité à inhiber in vitro lacroissance de Penicillium expansum et d’Aspergillus carbonarius ainsi que la production de patuline etd’ochratoxine A. Les souches les plus prometteuses ont été testées comme antagonistes au vignoble etau verger bio et conventionnel ainsi qu’en élaboration avec différents degrés de réussite. La filière cidredispose, à la suite de ce programme, d’une méthode de marquage de la patuline au 13C. Les tests decytotoxicité menés sur l’ascladiol et l’acide desoxypatulinique ont montré leur absence de toxicité. Enfin,les deux filières disposent de méthodes de criblage pour mettre rapidement en œuvre desexpérimentations complémentaires en cas de contamination naturelle liée aux évolutions du climat etdes pratiques.

International audience; In rainfed agriculture systems, rainfall water management (harvesting, storage, and efficient use) is a key issue. At local scale (i.e., from 100 m to 50 km), the impact of rainfall spatial and temporal variability on crop water availability is seldom addressed. In order to accurately depict the space and time variations of rainfall at local scale, a dense rain-gauges network composed of 45 rain-gauges has been deployed over 28-km2 area, in Burgundy vineyards (North-East France). Rainfall data collected by each rain gauge from 2014 to 2016 were used as input variables in the Lebon et al. (2003) grapevine water balance model. All other climate variables, vineyard, and soil parameters were kept the same for each simulation in order to capture the impact of the sole spatial variability of rainfall on vineyard water status. As rainfall dynamics impact on the vineyard depends on the soil water content, water balance was modeled considering soils with low (50 mm) and medium (150 mm) soil water-holding capacities, representative of the soils of the area. The impact of modeled soil water availability for grapevine was assessed using the water deficit stress index (WDSI), i.e., the relative stomatal conductance. Local rainfall variability throughout the vine vegetative period leads to large variations in WDSI; it varied up to 0.3 within the study area due to because of rainfall spatial variability. Using a set of 34 weather stations at mesoscale level over Burgundy (186 km from North to South), we showed that local rainfall might contribute to change in grapevine water status as large as 50% of the simulated regional water balance spatial variability. Our results indicate that local rainfall and its impacts on agricultural production are probably not sufficiently considered in farming systems, potentially leading to inaccurate water management (cover-crop, irrigation) due to sparse rainfall network.

Ce numéro comprend les articles correspondant aux présentations du Colloque Casdar 2018.; This project, product of RMT “Fertilisation et Environnement”, aimed at developing a prototype ofnitrogen fertilization management for perennial crops, by adapting an already existing and innovativetool used for annual crops (AzoFert®) and based on balance sheet method. The prototype is a computerprogram with internet access. The user has to document several categories of data: location, soil, crop(cultural route, aimed yield). An operational and friendly interface was developed, even if improvementsare still required. Validation results of prototype N-Pérennes are encouraging for vine growing comparedwith empirical recommendations (50 % of correct recommendations). For fruit growing, the lack ofexperimental references led to a low number of correct recommendations. Work of programming,configuration and validation in practical use is needed to get an operational tool. Other perspectives,widening prototype objective, are also possible.; Ce projet, né du RMT Fertilisation et Environnement, vise à mettre au point un prototype d'outil degestion de la fertilisation azotée pour les plantes pérennes, en se basant sur un outil déjà existant etinnovant, utilisé sur les grandes cultures (AzoFert®) et basé sur la méthode du bilan. L'accent est missur le fait que le projet doit aboutir à un prototype à caractère générique et non spécifique d'une région.Le prototype se présente sous forme informatique, avec accès par internet. L’utilisateur doit renseignerplusieurs catégories de données : localisation, sol, culture (itinéraire cultural, rendement visé). Uneinterface opérationnelle et conviviale a été développée, même si des améliorations restent à faire. Lesrésultats obtenus avec le prototype N-Pérennes sont encourageants en viticulture comparativement àdes préconisations empiriques (50 % de préconisations correctes). En arboriculture, le manque deréférences expérimentales a induit un faible nombre de validations réalisées. Pour que le prototypedevienne un outil opérationnel, il restera à réaliser à la fois du travail de programmation et deparamétrage, et une validation sur un plus grand nombre de situations, notamment en conditions réellesd’utilisation de l’outil. D’autres perspectives, élargissant l’objectif du prototype, sont égalementenvisageables.

International audience; Spread patterns of a Grapevine leafrollassociated virus 1 (GLRaV-1) epidemic and a mealybug infestation survey over 10 year were recorded in two Burgundy French vineyards to investigate the relation between them. The temporal evolution of leafroll spread at both study sites was compared on disease incidence data with logisticregression models. We first tested if the spatial distribution of the disease and the mealybug were aggregated using permutation methods, then we tested the independence between the two spatial patterns by randomly shifting one pattern. In Bonzon, an increase from 5 % to 86 % of leafroll prevalence was observed over an 8-year time span, whereas leafroll prevalence remained stable around 5 % in Marsannay-la-Côte during the same period. In Bonzon, the disease spread rapidly from older neighbouring vineyards in four main patches while no spread of the disease was recorded from infected vines in Marsannay-la-Côte. The mealybug Phenacoccus aceris was recorded on 74 % of vines in Bonzon throughout the study and only 6 % of vines in Marsannay-la-Côte. In the latter location, the disease was not associated with the presence of the mealybug, so that it may have arisen from infected plant material escaping the sanitary inspection. In onzon, the significant statistical correlation between the mealybug distribution and diseased plants suggests that P. aceris was responsible for the rapid spread of GLRaV-1 in the vineyard. This is the first report of GLRaV-1 natural spread in Europe

National audience; The NemadexAB rootstock, created by Alain Bouquet at INRA Montpellier and registered in 2011, is able to delay the contaminations of the vines by GFLV thanks to the presence of Muscadinia rotundifolia in his parenthood. But it remains difficult to grow, with a poor conferred vigor to scion and a susceptibility to both chlorosis and drought. For those reasons, NemadexAB is considered as a qualitative and ‘niche’ rootstock, to be used as Riparia or 101-14. This article reviews its characteristics on both ability to delay GFLV contaminations and agronomical requirements from the current experimental trials. It also issues prospective work for an integrated way of reducing fanleaf decline.; Le porte-greffe NemadexAB, obtenu par Alain Bouquet à l’INRA de Montpellier est inscrit au catalogue depuis 2011, présente des aptitudes à retarder les contaminations par la virose du court-noué du fait de son parent Muscadinia rotundifolia. Mais c’est un porte-greffe exigent, présentant une faible vigueur conférée et une sensibilité à la chlorose et à la sécheresse. Pour ces raisons, le Nemadex AB est un porte-greffe qualitatif que l’on peut qualifier « de niche », s’utilisant dans les mêmes conditions que le Riparia ou le 101-14. Cet article fait la synthèse des expérimentations en cours concernant le retard à la contamination et de comportement agronomique, et dresse les conditions à respecter pour son utilisation ainsi que les perspectives de recherche qui se dessinent en vue d’obtenir un itinéraire intégré de lutte contre le court-noué.

International audience; This study analyzes the effects of some important factors of champagne technology on the ellipticity and Brewster angle microscopy (BAM) of the air/champagne interface in view of using the optical properties of the adsorption layer of base wine to forecast the stability of the champagne bubble collar. Using standard, ultrafiltered, and ultraconcentrated wines it was observed that champagne can lose amphiphilic macromolecules which adsorb on the inner glass wall of the bottle during storage, particles such as dead yeasts can adhere to the adsorption layer, a weak increase of the ethanol content during bottle fermentation can reduce significantly the ellipticity of the adsorption layer, and CO(2) has no significant effect on the properties of that layer. Surprisingly, no visible differences of the adsorption layer were noticed between the experimental champagnes of the 2004 vintage of three vine varieties (Chardonnay, Pinot noir, and Pinot meunier). From analysis of all samples it is proposed that the mean value and standard deviation of the ellipticity measured during 30 min after pouring the wine in a Petri dish are physical quantities which satisfactorily characterize the adsorption layer of champagne. When needed, further characterization of the adsorption layer may be obtained by a detailed analysis of the kinetics of ellipticity during the same period and inspection of the BAM images of the interface.

International audience

International audience; In Precision Viticulture, multispectral imaging systems are currently used in remote sensing for vineyard vigor characterization but few are employed in proximal sensing. This work presents the potential of a proximal multispectral imaging system mounted on a track-laying tractor equipped with a Greenseeker RT-100 to provide an NDVI index. The camera acquired visible and near-infrared images which were calibrated in reflectance. Vegetation indices were computed and compared to Greenseeker data. From two of the resulting datasets, a spatio-temporal study of foliage description through both optical systems is presented. This first study assessed the proximal imagery regarding the similarity of results.

Animateur : Didier MerdinogluBAPSAR; absent

International audience; Spread patterns of a Grapevine leafrollassociated virus 1 (GLRaV-1) epidemic and a mealybug infestation survey over 10 year were recorded in two Burgundy French vineyards to investigate the relation between them. The temporal evolution of leafroll spread at both study sites was compared on disease incidence data with logisticregression models. We first tested if the spatial distribution of the disease and the mealybug were aggregated using permutation methods, then we tested the independence between the two spatial patterns by randomly shifting one pattern. In Bonzon, an increase from 5 % to 86 % of leafroll prevalence was observed over an 8-year time span, whereas leafroll prevalence remained stable around 5 % in Marsannay-la-Côte during the same period. In Bonzon, the disease spread rapidly from older neighbouring vineyards in four main patches while no spread of the disease was recorded from infected vines in Marsannay-la-Côte. The mealybug Phenacoccus aceris was recorded on 74 % of vines in Bonzon throughout the study and only 6 % of vines in Marsannay-la-Côte. In the latter location, the disease was not associated with the presence of the mealybug, so that it may have arisen from infected plant material escaping the sanitary inspection. In onzon, the significant statistical correlation between the mealybug distribution and diseased plants suggests that P. aceris was responsible for the rapid spread of GLRaV-1 in the vineyard. This is the first report of GLRaV-1 natural spread in Europe

Animateur : Didier MerdinogluBAPSAR; absent

absent

Grapevine leafroll disease is caused by grapevine leafroll-associated viruses (GLRaVs). These viruses are common in vineyards worldwide and often associated with vitiviruses that are involved in the rugose wood complex of grapevine. Ten mealybug species are known as vectors of one or several of these grapevine viruses, including the apple mealybug Phenacoccus aceris which is widespread in Holarctic regions and able to transmit Grapevine leafroll-associated virus-1 and -3 (GLRaV-1 and -3). Our aim was to characterize the transmission features of leafroll viruses by Phenacoccus aceris in order to better understand the contribution of this mealybug to leafroll epidemics. Results showed that Phenacoccus aceris is able to transmit GLRaV-1, -3, -4, -5, -6, and -9 to grapevine but not GLRaV-7. This is the first report of GLRaV-6 transmission by a mealybug. Also, for the first time it was shown that Phenacoccus aceris could vector vitiviruses Grapevine virus A (GVA) and Grapevine virus B (GVB). First instar nymphs were the most efficient stage in transmitting GLRaV-1, -3, and GVA. This research sheds light on the transmission biology of grapevine viruses by Phenacoccus aceris and represents a step forward to leafroll disease management.Grapevine leafroll disease is caused by grapevine leafroll-associatedviruses (GLRaVs). These viruses are common in vineyards worldwideand often associated with vitiviruses that are involved in the rugose woodcomplex of grapevine. Ten mealybug species are known as vectors of oneor several of these grapevine viruses, including the apple mealybugPhenacoccus aceris which is widespread in Holarctic regions and able totransmit Grapevine leafroll-associated virus-1 and -3 (GLRaV-1 and -3).Our aim was to characterize the transmission features of leafroll virusesby Phenacoccus aceris in order to better understand the contribution ofthis mealybug to leafroll epidemics. Results showed that Phenacoccusaceris is able to transmit GLRaV-1, -3, -4, -5, -6, and -9 to grapevine butnot GLRaV-7. This is the first report of GLRaV-6 transmission by amealybug. Also, for the first time it was shown that Phenacoccus aceriscould vector vitiviruses Grapevine virus A (GVA) and Grapevine virus B(GVB). First instar nymphs were the most efficient stage in transmittingGLRaV-1, -3, and GVA. This research sheds light on the transmissionbiology of grapevine viruses by Phenacoccus aceris and represents a stepforward to leafroll disease management.

La dégradation physique des sols agricoles et forestiers liée au tassement lors des passages d’engins est une préoccupation importante des acteurs de l’agriculture et de la forêt. Mais au-delà de ce cercle, elle concerne également tous ceux qui se préoccupent des conséquences environnementales de l’agriculture et de la gestion forestière. En effet, le tassement des sols modifie a des conséquences lourdes sur plusieurs processus tels que l’érosion hydrique, la dénitrification, le stockage du carbone, la préservation de la biodiversité, la production. Dans ce cadre, le projet DST (Dégradation physique des Sols agricoles et forestiers liée au Tassement) proposait cinq volets de recherche : impact, prévision, prévention, suivi et cartographie du tassement en France métropolitaine. Il a reposé sur l’utilisation de modèles de tassement des sols et de fonctionnement du système sol/plante pour étudier les conséquences sur les cultures et l’environnement, via la modification des propriétés (stockage, transfert, mécaniques) des sols. Ce projet transversal, associant des laboratoires de recherche travaillant en agriculture, en géophysique ou en génie civil et des organismes professionnels, s’est aussi appuyé sur des expérimentations variées, en laboratoire et sur le terrain. Les principaux résultats sont présentés dans cet article. Ils concernent : (i) l’impact du tassement, avec la mise en évidence d’un seuil d’indice des vides en sol limoneux (0,15 m3.m 3 dans les sols limoneux), au-delà duquel les performances des cultures et les propriétés hydrodynamiques sont à coup sûr affectées, (ii) la modélisation, le projet ayant débouché sur la mise au point d’un modèle 2-D de prévision de la déformation des sols, (iii) le suivi, avec l’évaluation de méthodes géophysiques, non destructrices, permettant la cartographie des zones tassées, (iv) la prévention, à travers le développement d’un outil de prévision de l’humidité du sol et des jours disponibles et, (v) la cartographie des zones à risques en France., Physical degradation of agricultural and forest soils due to compaction is an important concern for the actors in agriculture, forest and environment. Many questions are still pending on the importance of this degradation, the evaluation of its impact on environment, the effect of changes of climate and practices, its natural remediation. The DST (Agricultural and Forest Soil Degradation induced by Compaction ?) project has proposed a research action on soil compaction in metropolitan France in order to : quantify the impacts of soil compaction on important soil environmental functions ; identify the conditions leading to compaction ; prevent the occurrence of these conditions ; monitor the evolution of soil structure after compaction. The project was structured in five working packages : impact, prediction, prevention, follow-up and cartography. It was based on modelling (hydrology, soil deformation, soil-crop interactions models) to study the occurrence of compaction and its impacts on crop growth and the environment. It also aimed at developing non-destructive methods to monitor soil structure deformation. The project associated research laboratories working in agriculture, geophysics or civil engineering and extension services members and was also based on field and laboratory experimentations, performed in various conditions (field crops, vineyards, forests). Mains results concerned : (i) impacts of compaction, as we demonstrated the existence of a threshold value for the structural void ratio (0,15 m3m3 in loamy soils) beyond which crop performances and hydrological properties are systematically affected ; (ii) modelling, with a 2-D model of soil deformation ; (iii) compaction assessment, based on non-destructive geophysical methods ; (iv) prevention of compaction, with a predictive model of soil water content and (v) mapping of compaction risks in France, based on the knowledge acquired during the project., La degradación física de los suelos agrícolas y forestales ligada a la compactación durante los pasajes de maquinarias está una preocupación importante de los actores de la agricultura y de la gestión forestal. Pero más allá de este círculo, concierne igualmente todos los que se preocupan de las consecuencias ambientales de la agricultura y de la gestión forestal. En efecto, la compactación de los suelos modifica sus propiedades y así varias funciones importantes para los procesos tales que erosión hídrica, denitrificación, almacenamiento del carbono, preservación de la biodiversidad. En este cuadro, el proyecto DST propuso cinco direcciones de investigación : impacto, previsión, prevención, seguimiento y cartografía de la compactación. Se basó en la utilización de modelos de compactación de los suelos y de funcionamiento del sistema para estudiar las consecuencias sobre los cultivos y el medio ambiente, vía la modificación de las propiedades (almacenamiento, transferencia, mecánicas) de los suelos. Este proyecto transversal, que asocia laboratorios de investigación que trabajan en agricultura, geofísica, o ingeniera civil y los organismos profesionales, se apoyo también sobre experimentaciones variadas, en laboratorio y en el campo. En este articulo se presenta los principales resultados que conciernen : (i) el impacto de la compactación, con la puesta en evidencia de un umbral de índice de vacios en suelo limoso, más allá del cual las performances de los cultivos y las propiedades hidrodinámicas están, desde luego, impactadas, (ii) la modelización, el proyecto desemboco sobre la realización de un modelo 2-D de previsión de la deformación de los suelos, (iii) el seguimiento, con la evaluación de métodos geofísicos, no destructivos que permiten la cartografía de las zonas compactadas, (iv) la prevención, a través del desarrollo de una herramienta de previsión de la humedad del suelo y de los días disponibles y (v) la cartografía de las zonas con riesgos en Francia.

International audience; Analysis of wines from different grape varieties marked by sometimes intense aromatic nuances of fresh mushroom was performed by gas chromatography coupled with olfactometry. This analysis has led to the identification of several odoriferous zones, which were recalling a fresh mushroom odor. Two trace compounds responsible for these odoriferous zones, 1-nonen-3-one and 1-octen-3-one, have been identified and their content has been determined by using either a multidimensional gas chromatography technique coupled to olfactometry and mass spectrometry detection (in the case of 1-nonen-3-one) or the preparation of the derivative with O-2,3,4,5,6-pentafluorobenzylhydroxylamine hydrochloride in the presence of the deuterated form, as the internal standard (in the case of 1-octen-3-one), then gas chromatography coupled to mass spectrometry detection. The assays allowed the quantification of these compounds at concentration levels sometimes well above their detection and recognition olfactory threshold. We show that adding nitrogen compounds to the altered wines, such as an amino acid (glycine) or a tripeptide (glutathione), led to lower concentrations of 1-octen-3-one in wines and diminished smell of fresh mushrooms. The study of the reaction in a model medium, whose composition is close to wine, by liquid chromatography coupled to mass spectrometry demonstrated the formation of adducts between 1-octen-3-one and glycine, and 1-octen-3-one and glutathione characterized by NMR.

Background The composition of grapevine berry at harvest is a major determinant of wine quality. Optimal oenological maturity of berries is characterized by a high sugar/acidity ratio, high anthocyanin content in the skin, and low astringency. However, harvest time is still mostly determined empirically, based on crude biochemical composition and berry tasting. In this context, it is interesting to identify genes that are expressed/repressed specifically at the late stages of ripening and which may be used as indicators of maturity. Results Whole bunches and berries sorted by density were collected in vineyard on Chardonnay (white cultivar) grapevines for two consecutive years at three stages of ripening (7-days before harvest (TH-7), harvest (TH), and 10-days after harvest (TH+10)). Microvinification and sensory analysis indicate that the quality of the wines made from the whole bunches collected at TH-7, TH and TH+10 differed, TH providing the highest quality wines. In parallel, gene expression was studied with Qiagen/Operon microarrays using two types of samples, i.e. whole bunches and berries sorted by density. Only 12 genes were consistently up- or down-regulated in whole bunches and density sorted berries for the two years studied in Chardonnay. 52 genes were differentially expressed between the TH-7 and TH samples. In order to determine whether these genes followed a similar pattern of expression during the late stages of berry ripening in a red cultivar, nine genes were selected for RT-PCR analysis with Cabernet Sauvignon grown under two different temperature regimes affecting the precocity of ripening. The expression profiles and their relationship to ripening were confirmed in Cabernet Sauvignon for seven genes, encoding a carotenoid cleavage dioxygenase, a galactinol synthase, a late embryogenesis abundant protein, a dirigent-like protein, a histidine kinase receptor, a valencene synthase and a putative S-adenosyl-L-methionine:salicylic acid carboxyl methyltransferase. Conclusions This set of up- and down-regulated genes characterize the late stages of berry ripening in the two cultivars studied, and are indirectly linked to wine quality. They might be used directly or indirectly to design immunological, biochemical or molecular tools aimed at the determination of optimal ripening in these cultivars.

National audience; Physical degradation of agricultural and forest soils due to compaction is an important concern for the actors in agriculture, forest and environment. Many questions are still pending on the importance of this degradation, the evaluation of its impact on environment, the effect of changes of climate and practices, its natural remediation. The DST (Agricultural and Forest Soil Degradation induced by Compaction ?) project has proposed a research action on soil compaction in metropolitan France in order to : quantify the impacts of soil compaction on important soil environmental functions ; identify the conditions leading to compaction ; prevent the occurrence of these conditions ; monitor the evolution of soil structure after compaction. The project was structured in five working packages : impact, prediction, prevention, follow-up and cartography. It was based on modelling (hydrology, soil deformation, soil-crop interactions models) to study the occurrence of compaction and its impacts on crop growth and the environment. It also aimed at developing non-destructive methods to monitor soil structure deformation. The project associated research laboratories working in agriculture, geophysics or civil engineering and extension services members and was also based on field and laboratory experimentations, performed in various conditions (field crops, vineyards, forests). Mains results concerned : (i) impacts of compaction, as we demonstrated the existence of a threshold value for the structural void ratio (0,15 m3m3 in loamy soils) beyond which crop performances and hydrological properties are systematically affected ; (ii) modelling, with a 2-D model of soil deformation ; (iii) compaction assessment, based on non-destructive geophysical methods ; (iv) prevention of compaction, with a predictive model of soil water content and (v) mapping of compaction risks in France, based on the knowledge acquired during the project.; La degradación física de los suelos agrícolas y forestales ligada a la compactación durante los pasajes de maquinarias está una preocupación importante de los actores de la agricultura y de la gestión forestal. Pero más allá de este círculo, concierne igualmente todos los que se preocupan de las consecuencias ambientales de la agricultura y de la gestión forestal. En efecto, la compactación de los suelos modifica sus propiedades y así varias funciones importantes para los procesos tales que erosión hídrica, denitrificación, almacenamiento del carbono, preservación de la biodiversidad. En este cuadro, el proyecto DST propuso cinco direcciones de investigación : impacto, previsión, prevención, seguimiento y cartografía de la compactación. Se basó en la utilización de modelos de compactación de los suelos y de funcionamiento del sistema para estudiar las consecuencias sobre los cultivos y el medio ambiente, vía la modificación de las propiedades (almacenamiento, transferencia, mecánicas) de los suelos. Este proyecto transversal, que asocia laboratorios de investigación que trabajan en agricultura, geofísica, o ingeniera civil y los organismos profesionales, se apoyo también sobre experimentaciones variadas, en laboratorio y en el campo. En este articulo se presenta los principales resultados que conciernen : (i) el impacto de la compactación, con la puesta en evidencia de un umbral de índice de vacios en suelo limoso, más allá del cual las performances de los cultivos y las propiedades hidrodinámicas están, desde luego, impactadas, (ii) la modelización, el proyecto desemboco sobre la realización de un modelo 2-D de previsión de la deformación de los suelos, (iii) el seguimiento, con la evaluación de métodos geofísicos, no destructivos que permiten la cartografía de las zonas compactadas, (iv) la prevención, a través del desarrollo de una herramienta de previsión de la humedad del suelo y de los días disponibles y (v) la cartografía de las zonas con riesgos en Francia.; La dégradation physique des sols agricoles et forestiers liée au tassement lors des passages d’engins est une préoccupation importante des acteurs de l’agriculture et de la forêt. Mais au-delà de ce cercle, elle concerne également tous ceux qui se préoccupent des conséquences environnementales de l’agriculture et de la gestion forestière. En effet, le tassement des sols modifie a des conséquences lourdes sur plusieurs processus tels que l’érosion hydrique, la dénitrification, le stockage du carbone, la préservation de la biodiversité, la production. Dans ce cadre, le projet DST (Dégradation physique des Sols agricoles et forestiers liée au Tassement) proposait cinq volets de recherche : impact, prévision, prévention, suivi et cartographie du tassement en France métropolitaine. Il a reposé sur l’utilisation de modèles de tassement des sols et de fonctionnement du système sol/plante pour étudier les conséquences sur les cultures et l’environnement, via la modification des propriétés (stockage, transfert, mécaniques) des sols. Ce projet transversal, associant des laboratoires de recherche travaillant en agriculture, en géophysique ou en génie civil et des organismes professionnels, s’est aussi appuyé sur des expérimentations variées, en laboratoire et sur le terrain. Les principaux résultats sont présentés dans cet article. Ils concernent : (i) l’impact du tassement, avec la mise en évidence d’un seuil d’indice des vides en sol limoneux (0,15 m3.m 3 dans les sols limoneux), au-delà duquel les performances des cultures et les propriétés hydrodynamiques sont à coup sûr affectées, (ii) la modélisation, le projet ayant débouché sur la mise au point d’un modèle 2-D de prévision de la déformation des sols, (iii) le suivi, avec l’évaluation de méthodes géophysiques, non destructrices, permettant la cartographie des zones tassées, (iv) la prévention, à travers le développement d’un outil de prévision de l’humidité du sol et des jours disponibles et, (v) la cartographie des zones à risques en France.

National audience; This project aimed at elaborating a strategy to control production of the molecules at the origin of the"mould" tastes on wines in several French wine-producing regions, by characterizing all the fungusspecies responsible for this production and by establishing simple sensory descriptors corresponding tothese defaults. The project succeeded in i) the characterization and the quantification of microorganisms producing these molecules as well as the follow-up of their changes during the maturity of the grape; ii) implementation of a collection of molds; iii) understanding of the effect of the agro-wine practices on the growth of molds and on the production of these molecules; iv) definition and validation of sensory descriptors associated to the earthy defaults, and also the analytic methods associated.; Ce projet vise à élaborer une stratégie de lutte contre la production des molécules néfastes à l’origine des ‘goûts moisi-terreux’ (GMT), et de l’’arôme de champignon frais (ACF)’ sur les vins de plusieurs régions viticoles françaises, en caractérisant l’ensemble des espèces fongiques responsables de cette production et en établissant des descripteurs sensoriels simples correspondant aux défauts recherchés, ainsi que les méthodes analytiques pour les doser. Le projet a abouti à la caractérisation et quantification des micro-organismes producteurs de ces molécules ainsi que le suivi de leur évolution, au cours de la maturité du raisin; la mise en place d’une collection de moisissures; la compréhension de l’effet des pratiques agro-viticoles sur la croissance des moisissures et sur la production de ces molécules; la définition et validation de descripteurs sensoriels associés aux défauts terreux, de même que les méthodes analytiques associées.

National audience

National audience; L’enroulement viral est une maladie mondialement répandue entraînant des pertes notables dans nombre de régions viticoles. Onze virus différents sont associés aux symptômes de l’enroulement les Ampélovirus GLRaV-1 et -3 (Grapevine leafroll-associated virus, Closteroviridae) étant les espèces les plus communes en France. D’autres virus, les Vitivirus GVA et GVB (Grapevine virus A & B, Betaflexiviridae), sont souvent détectés dans la vigne associés aux virus de l’enroulement.

International audience; Botrytis bunch rot of grapes is mainly controlled by applying fungicides at three crop growth stages: the end of flowering (BBCH 68), bunch closure (BBCH 77) and the beginning of veraison (BBCH 81). The hydroxyanilide derivative fenhexamid is among the most effective fungicides registered to control Botrytis cinerea. Its effectiveness was examined in relation to spray timing, fungicide resistance and defense responses of grapevine. Overall, the earlier fenhexamid was applied, the more effective it was at controlling B. cinerea. Frequencies of B. cinerea strains which were resistant to fungicides were evaluated at harvest. The frequencies of resistant phenotypes were similar among treatments and years with the exception of a class of multidrug resistant strain (MDR 2) whose frequency appeared to increase after fenhexamid applications. If current spray programs including fenhexamid appear to control bunch rot at the current MDR frequency, a propagation of MDR 2 strains might lead to a decline in disease control. Finally, defense responses were studied in grapevine flowers/berries following fenhexamid application. None of the defense processes tested was induced in flowers/berries at stages 68 and 77. Only an increase in chitinase activity was observed in treated-berries at stage 81, suggesting that fenhexamid effectiveness was not related to a stimulation of defense responses.

Dans le cadre du Festival international de la diversité culturelle de l’UNESCO, la Délégation permanente de Thaïlande a organisé des manifestations culturelles, artistiques et scientifiques autour du thème « La soie thaïlandaise : un patrimoine culturel » entre le 18 et le 20 mai 2009 à la Maison de l’UNESCO à Paris. Cet événement se composait d'une série de colloques, d’une exposition-démonstration, d’un spectacle suivi par un défilé de mode.La soie thaïlandaise, souvent appelée « La Reine des textiles », est un produit réputé par sa beauté et son identité. Le savoir-faire de ce patrimoine est transmis de génération en génération et inclut la tradition et la culture dans chaque étape de fabrication (dévidage , filage et tissage).Arrivé en Thaïlande au lendemain de la guerre de 1944, l’Américain Jim Thompson est séduit par le pays et se passionne pour la soie tissée à la main, à l’époque tombée dans l’oubli. Dessinateur et coloriste de talent, il développe la production de la soie thaïlandaise et crée en quelques mois la Thai Silk Company qui fait travailler 200 tisseurs. La participation de Jim Thompson fut fondamentale au renouveau du tissage de la soie thaïlandaise et à la réputation qu’elle a acquit aujourd’hui., เนื่องในโอกาสเทศกาลความหลากหลายทางวัฒนธรรมนานาชาติ คณะผู้แทนถาวรไทยประจำองค์การความร่วมมือทางการศึกษา วิทยาศาสตร์และวัฒนธรรมระหว่างประเทศหรือยูเนสโก (UNESCO) ได้จัดงานวัฒนธรรม ศิลปะและวิชาการภายใต้หัวข้อ “ผ้าไหมไทย : มรดกวัฒนธรรม” ระหว่างวันที่ ๑๘ ถึง ๒๐ พฤษภาคม พ.ศ. ๒๕๕๒ ณ องค์การยูเนสโก งานดังกล่าวประกอบด้วยสัมมนา นิทรรศการ การสาธิต การแสดงและการเดินแบบผ้าไหมไทยหรือรู้จักกันในฐานะ ราชินีของผ้า เป็นผลิตภัณฑ์ที่มีชื่อเสียงทั้งในด้ามความสวยงามและความเป็นเอกลักษณ์ การผลิตไหมไทยเป็นมรดกทางวัฒนธรรมที่สืบต่อกันมาจากบรรพบุรุษสู่ลูกหลาน ในแต่ละขั้นตอนของการผลิตตั้งแต่การสาวไหม การทอผ้าไหมสะท้อนให้เห็นถึงวัฒธรรมและประเพณีการผลิตผ้าไหมในประเทศไทยมีมาตั้งแต่สมัยอารยธรรมบ้านเชียง(มีอายุประมาณ ๓,๐๐๐ ปีก่อนคริสตกาล) ในภาคตะวันออกเฉียงเหนือของประเทศ ในปีพ.ศ. ๒๔๔๕ พระบาทสมเด็จพระจุลจอมเกล้าเจ้าอยู่หัวมีพระราชดำริในการยกคุณภาพการผลิตผ้าไหมไทย โดยการเชิญผู้เชี่ยวชาญจากประเทศญี่ปุ่นมาอบรบเทคนิคการผลิต การเลี้ยงไหมและการทอผ้าไหมแก่ชาวบ้าน แต่อย่างไรก็ตามผ้าไหมไทยก็ยังไม่เป็นที่รู้จักในต่างประเทศ จนกระทั่งจิม ทอมสัน ชาวอเมริกันได้นำผ้าไหมไทยไปตัดเย็บเป็นเครื่องแต่งกายนักแสดงในละครเรื่อง กษัตริย์และฉัน ในปี พ.ศ. ๒๔๙๔ นับแต่นั้นมาผ้าไหมไทยก็เป็นที่นิยมในระดับนานาชาติประวัติความเป็นมาและศิลปะการทักทอที่เป็นเอกลักษณ์กลายเป็นมูลค่าเพิ่มที่สำคัญต่อผลิตภัณฑ์ผ้าไหมของไทยซึ่งเป็นที่นิยมจากชาวไทยและชาวต่างชาติในปัจจุบัน ผ้าไหมไทยเป็นของที่ระลึกทำรายได้ปีละประมาณ ๓,๐๐๐ ล้านบาท และส่งออกไปยังตลาดต่างประเทศปีละ ๙๐๐-๑,๐๐๐ ล้านบาทเพื่อเป็นการพัฒนาไหมไทยให้มีคุณภาพและได้มาตรฐานสากล กระทรวงเกษตรและสหกรณ์ได้ประกาศใช้เครื่องหมายรับรองตรานกยูงซึ่งได้รับพระราชทานจากสมเด็จพระนางเจ้าพระบรมราชินีนาถ เป็นเครื่องหมายรับรองชนิดเส้นไหม และกรรมวิธีการผลิตผ้าไหม ซึ่งสามารถแบ่งได้เป็น ๔ ชนิด คือ นกยูงสีทองเป็นผ้าไหมที่ผลิตโดยใช้เส้นไหมและวัตถุดิบตลอดจนกระบวนการผลิตที่เป็นการอนุรักษ์ภูมิปัญญาพื้นฐานดั้งเดิมของไทย นกยูงสีเงินเป็นผ้าไหมที่ผลิตขึ้นโดยยังคงอนุรักษ์ภูมิปัญญาพื้นบ้านผสมผสานกับการประยุกต์ใช้เครื่องมือและกระบวนการผลิตบางขั้นตอน นกยูงสีน้ำเงินเป็นผ้าไหมที่ผลิตด้วยภูมิปัญญาของไทยแบบประยุกต์ใช้เทคโนโลยีการผลิตเข้ากับสมัยนิยมและเชิงธุรกิจ นกยูงสีเขียวเป็นผ้าไหมที่ผลิตด้วยกระบวนการผลิตและเทคโนโลยีสมัยใหม่ผสมผสานภูมิปัญญาไทยในด้านลวดลายและสีสันระหว่างเส้นใยแท้กับเส้นใยอื่นๆ ที่มาจากธรรมชาติ หรือเส้นใยสังเคราะห์รูปแบบต่างๆขอขอบคุณ คุณอรชาต สืบสิทธิ์ รองผู้แทนถาวรไทยประจำยูเนสโก ในการอนุญาตคณะศูนย์จดหมายเหตุโสตทัศน์เพื่อการวิจัยถ่ายทำเทศกาลวัฒนธรรมนี้ รวมทั้งเผยแพร่มรดกวัฒนธรรมนี้ต่อผู้ชมจากทั่วโลก และคุณจุลลดา มีจุล หัวหน้าฝ่ายวิชาการและพัฒนาเครือข่าย สถาบันพิพิธภัณฑ์การเรียนรู้แห่งชาติ ในการเป็นล่ามภาษาไทยและฝรั่งเศสในสัมมนาต่างๆตลอดเทศกาล

International audience; A bubble collar is expected on a champagne flute. The mechanisms of formation of that collar have been tackled. by an integrated approach including the analysis of the adsorption layer occurring at the air/champagne interface, the measurement of the lifetime of isolated air bubbles blown in degassed champagne and the kinetics of the area covered by the collar after pouring in a flute. In the case of experimental champagnes where the surface concentration of the adsorption layer is varied, very good correlations were observed between the adsorption layer parameters, the lifetime of isolated bubbles and the kinetics of the collar area. These correlations were expected from the physics of bubbles and foams. The same parameters were determined on commercial samples bought in supermarkets. The adsorption layer concentrations were found to be in the same range as those of the experimental products, the lifetimes of isolated bubbles were often shorter and the area of the collar was much less stable than with the experimental samples. Moreover. with the commercial samples, no correlations were noticed between the measured parameters. It is hypothesised that the main differences between the experimental and the commercial samples come from the wine making technologies including the ageing on lees and in bottle.

International audience; The structure and the chemical composition of the layer adsorbed at interfaces involving champagne have been investigated using native champagne, as well as ultrafiltrate (UFch) and ultraconcentrate (UCch) obtained by ultrafiltration with a 10(4) nominal molar mass cutoff. The layer adsorbed at the air/liquid interface was examined by surface tension and ellipsometry kinetic measurements. Brewster angle microscopy demonstrated that the layer formed on polystyrene by adsorption or drop evaporation was heterogeneous, with a domain structure presenting similarities with the layer adsorbed at the air/liquid interface. The surface chemical composition of polystyrene with the adlayer was determined by X-ray photoelectron spectroscopy (XPS). The contribution of champagne constituents varied according to the liquid (native, UFch, and UCch) and to the procedure of adlayer formation (evaporation, adsorption, and adsorption + rinsing). However, their chemical composition was not significantly influenced either by ultrafiltration or by the procedure of deposition on polystyrene. Modeling this composition in terms of classes of model compounds gave approximately 35% (w/w) of proteins and 65% (w/w) of polysaccharides. In the adlayer, the carboxyl groups or esters represent about 18% of carbon due to nonpolypeptidic compounds, indicating the presence of either uronic acids in the complex structure of pectic polysaccharides or of polyphenolic esters. This structural and chemical information and its relationship with the experimental procedures indicate that proteins alone cannot be used as a realistic model for the macromolecules forming the adsorption layer of champagne. Polysaccharides, the other major macromolecular components of champagne wine, are assembled with proteins at the interfaces, in agreement with the heterogeneous character of the adsorbed layer at interfaces.

An innovative mass spectrometry method was developed for determining mass distributions of tannin fractions that cannot be approached through direct MALDI-TOF analysis. It was applied to three procyanidin fractions with average degrees of polymerizations = 3, 9, and 28, respectively, and one gallotannin fraction (Tara tannin). The proposed approach consists of MALDI-TOF analysis of the soluble complexes formed between these tannin fractions and bovine serum albumin (BSA). Complexes were detected as an unresolved "hump" following the BSA signal, and spectra were mathematically processed to determine the parameters relative to the protein-tannin complexes, which are the number-average molecular weight (Mn), the weight-average molecular weight (Mw), and the polydispersity index (PI) for each tannin fraction. Regarding condensed tannins, results are consistent with those of the standard method (thiolysis followed by HPLC separation) for all tested fractions. The method was successfully applied to a hydrolyzable tannin fraction but no standard method is available for comparison., Comite Interprofessionnel des Vins de Champagne (CIVC) and Moet & Chandon Company

National audience; L'objectif de cette étude est de modéliser le transfert des pesticides vers les eaux de surface afin de pouvoir estimer l'impact général de l'utilisation de molécules récentes ou anciennes sur le bassin versant de la Vesle. Les études réalisées dans ce cadre concernent la contamination des retombées atmosphériques totales, le ruissellement en zone de vignoble, l'infiltration et la dynamique des pratiques phytosanitaires. Les premiers résultats des analyses des dépôts atmosphériques indiquent une contamination d'origine locale par la présence de molécules spécifiques à certaines cultures telles que la trifuraline, la terbuthylazine, le tébutame. Concernant l'atrazine et la simazine, molécules interdites depuis fin 2003, les concentrations maximales observées en 2004 sont encore, respectivement, de 38 et de 69 ng.L-1. Ces résultats soulignent l'importance de leur persistance dans les sols. L'étude sur le ruissellement a permis de mettre en évidence une différenciation de l'exportation en fonction des propriétés physicochimiques des molécules et deux processus de désorption rapide et lente des molécules contenues dans le sol. Les résultats de ces études seront intégrés dans un modèle de transfert de pesticides vers les eaux de surface.

Die Bodenverdichtung wird in Europa als ein wesentlicher Prozess für die physische Verschlechterung der Boden angesehen. Sie steht mit der Mechanisierung der landwirtschaftlichen und forstwirtschaftlichen Tätigkeit infolge des Einsatzes von schweren Maschinen im Zusammenhang. In Frankreich unterstützt das Ministerium für Ökologie und dauerhafte Entwicklung ein Programm über die "physische Verschlechterung der Böden durch Verdichtung" (DST). Ihr Ziel ist eine bessere Einschätzung und Verhütung der Bodenverdichtungen. Eine erste Aktion dieser Studie besteht darin, den durch Fahrzeugsüberfahrten verursachten durchschnittlichen Bodenstress nach Maßgabe der wesentlichsten Produktionstypen (Acker- Wein- und Waldbau) einzuschätzen. Zunächst einmal haben wir die Berechnungsmethode festgelegt, um den durchschnittlichen Bodendruck bei der Überfahrt eines Fahrzeuges besser zu veranschlagen. Wir haben insbesondere ausgehend von leicht zugänglichen Parametern unsere Arbeit auf die Einschätzung der Kontaktfläche zwischen dem Reifen und dem Boden konzentriert. Dann haben wir bei verschiedenen technischen Institutionen Untersuchungen durchgeführt, um eine Bestandsaufnahme der Eigenschaften der im Ackerbau, Wein- und Waldbau verwendeten Maschinen zu machen. Ausgehend von dieser Bestandsaufnahme haben wir für die verschiedenen Produktionstypen regionale Bodendruckkarten erstellt. In Bezug auf den Rübenanbau stellt diese Arbeit die Anstrengungen der französischen Landwirte für eine verminderte Bodenverdichtung bei der Bodenbearbeitung heraus. Dagegen ergibt sich bei der Rübenernte ein wesentlicher Bodendruck in Höhe von 150 kPa. Dies ist mit den bei den anderen Erntemaschinen und Transportfahrzeugen in Wein- und Waldbau festgestellten Werten vergleichbar., Soil compaction is a major process of soil physical degradation in EU. Soil compaction occurs when soil is subject to mechanical constraints through the use of heavy machinery in agriculture and Forestry. The French ministry of Ecology and sustainable development support a project DST on “Soil physical degradation by compaction”. The aim is to improve knowledge on compaction problems in France. A first work was to evaluate stress which is applied on the ground and the conditions in which they are applied for cropping, vineyard and forest system. First we determined the best way to calculate soil constraints from bibliography and some experiments. Especially the work was focused on the prediction of the contact area between tyre and soil from easily accessible parameters. The second step consisted in meeting the experts of each production, in order to make profit of their knowledge and expertise. From this inventory, we calculated the constraints by system and locating them on a chart of France. With regard to sugar beat production, we put into evidence the effort made by French farmers to limit soil compaction at seedbed preparation. In contrast sugar beat harvesting induces high constraints about 150kPa. Similar constraints at harvesting were found for vineyard and forestry systems., Le tassement des sols est reconnu comme un processus majeur de la dégradation physique des sols en Europe. Il est essentiellement lié à la mécanisation des activités agricoles et forestières qui impliquent des passages d’engins lourds. Au niveau de la France, le Ministère de l’Ecologie et du Développement Durable soutient un programme sur « la Dégradation physique des Sols liée au Tassement » (DST), qui a pour objectif de mieux évaluer et de prévenir les tassements des sols. Une première action de cette étude a consisté à estimer les contraintes moyennes causées par les passages d’engins en fonction des grands types de production : systèmes de grandes cultures, systèmes viticoles et forestiers. Dans un premier temps, nous avons déterminé la méthode de calcul pour mieux évaluer la contrainte moyenne au sol lors d’un passage d’engins. Nous avons en particulier centré notre travail sur la prédiction de l’aire de contact entre le pneu et le sol à partir de paramètres facilement accessibles. Dans un deuxième temps, nous avons réalisé une expertise auprès de différents Instituts techniques pour réaliser un inventaire des chantiers dans les systèmes de grande culture, viticoles et forestiers. A partir de cet inventaire, nous avons pu établir des cartes des contraintes induites par les différentes productions à un niveau régional et pour des chantiers moyens. Concernant la culture de la betterave, ce travail met en évidence l’effort réalisé par les agriculteurs français pour limiter les tassements lors de la préparation de sol. Par contre, la récolte de betterave engendre des contraintes élevées, de l’ordre de 150 kPa, comparables à celles engendrées par les chantiers de récolte ou de transport des autres productions étudiées.

National audience

National audience

International audience

International audience; Bubble and foam stability, which are essential for the hallmark of champagne, rely on the concentration of amphiphilic macromolecules originating from the grape, which form molecular layers at the interface between champagne and gas. Ellipsometry and Brewster angle microscopy experiments were conducted at the air–champagne interface to analyse the lateral organization of the layers of macromolecules. Several kinds of phase separations – leading in some cases to two-dimensional foams – were identified. At the beginning of layer formation, condensed domains develop at the expense of dilute domains. Thereafter, phase separations occur within the condensed domains. These findings may allow advances in the implementation of methods predicting bubble and foam stability of champagnes.

National audience

International audience

National audience

L'acidité est un facteur important de la qualité des vins de Champagne. La prédiction du niveau d'acidité est indispensable au choix de la filière d'élaboration des vins dès la réception des moûts. Les tests effectués montrent que les modèles basés sur les réseaux de neurones permettent d'obtenir une meilleure précision que des modèles linéaires ou quadratiques, même si ce degré de précision est encore inférieur à celui des méthodes analytiques. Le modèle réalisé à partir de données de laboratoire issues de mini-vinifications a été testé avec succès sur des données industrielles, démontrant en cela sa robustesse. Cet outil d'aide à la décision pourrait être utilisé à l'avenir par les oenologues pour l'optimisation des assemblages des vins, contribuant à l'amélioration de la qualité des vins de Champagne. / Acidity is an important factor in Champagne wine quality. Predicting acidity levels is therefore an indispensable requirement when determining which wine production process to use once the must has been supplied. Various tests which have been undertaken show that those models based on neutral network programming are more accurate than either linear or quadratic function models, although they still prove to be less accurate than the more conventional analytical methods. The model generated using laboratory data from small-scale wine-making processes, has been successfully tested on data from industrial-scale processes, indicating the model's robustness. This decision-making tool could in future be used by wine-makers to optimise blending and thus improve the quality of the Champagne region's wines.

The distribution of X index in 3 fields infected with grapevine fanleaf virus (GFLV) in the Champagne vine-growing region of France was studied on the basis of samples from each horizon of the pedological profile. The lowest nematode count was observed between 0 and 25 cm in the field with the highest clay content (Mesnil), and between 0 and 40 cm in the 2 fields with sandier soil textures. The highest nematode count was detected in the 55-70-cm horizon of the Mesnil field and below 90 cm in the chalk parent rock for the 2 other fields. In Mesnil, with a high nematode density, ie 5 to 120 individuals per kg fine soil, the GFLV infectious potential of Xiphinema was determined using the ELISA method in nematode samples of increasing size from 2 to 256 individuals. Differences in absorbance between the field population and a virus-free control population reared on fig roots was observed from sample sizes of two. This method might adequately characterize the infectious potential of a given population., La distribution de X index dans 3 parcelles atteintes de court-noué du vignoble Champenois est étudiée à partir d’échantillons prélevés au niveau de chaque horizon d’un profil pédologique. Les effectifs les plus faibles sont observés entre 0 et 25 cm dans la parcelle la plus argileuse (Mesnil) et entre 0 et 40 cm dans les 2 autres parcelles, de texture plus sableuse. Les effectifs les plus élevés sont retrouvés dans l’horizon 55-70 cm de la parcelle Mesnil et au-delà de 90 cm dans la roche mère de craie pour les 2 autres. Au Mesnil où les effectifs sont élevés (5-120 individus par kg de terre fine), l’état infectieux des Xiphinema est établi en détectant, par la méthode ELISA, la présence du virus du court-noué dans les nématodes répartis en groupes d’effectif croissant de 2 à 256 individus. Une différence de densité optique entre la population de la parcelle et une population témoin non virulifère élevée sur figuier est observée dès la modalité «2 individus». Une telle méthode paraît utilisable pour caractériser l’état infectieux d’une population donnée.

International audience; We studied the effect of soil cover (bare soil, mulch of barks or composted organic materials, grass cover) on soil N dynamics in various experimental vineyards located in Champagne area (France). Soil cores were sampled periodically to measure water and mineral N in soil profile during autumn and winter. These measurements were used in a simple dynamic model (LIXIM) to calculate nitrate leaching and N mineralization. N mineralization potential of soils were also determined in laboratory incubations in controlled conditions. In most sites, soil inorganic N contents (0-75 cm) varied between 20 and 60 kg N ha-1 , depending of the season. Soil inorganic N in plots receiving barks or composted barks or covered with grass did not differ significantly from control plots. Higher amounts of inorganic N were found in soils amended with refuse compost, peat or mixed compost (barks + farmyard manure) or composted farmyard manure. The model indicated that N leached varied from 8 to 77 kg N ha-1 and that the mean nitrate concentration in drained water was less than 50 mg NO3-L-1 except for plots receiving refuse compost or bark + farmyard manure compost. The calculated N mineralization varied from 9 to 45 kg N ha-1 over the autumn-winter period, i.e. 118 to 182 days. The N mineralization rate (Vp), expressed per 'normalised day' i.e. day at 15°C and field capacity, varied from 0.15 to 0.82 kg N ha-1 nd-1 , including all sites and experimental treatments. Effect of organic matter addition on Vp was only observed for long-term experimental sites where large amounts of organic nitrogen had been added to soil using peat, refuse compost or compost mixtures with barks and farmyard manure. The Vp values measured in laboratory incubations showed the same trends and were in the same order of magnitude than those calculated with LIXIM model using in situ data. In average, the values measured in laboratory incubations underestimated the actual N mine-ralization in field conditions. The model was used to predict N mineralization and inorganic N in soil during the vegetative period using Vp values. It allowed to estimate the N uptake by vine: 10 ± 5 kg N ha-1 at flowering and 57 ± 5 kg N ha-1 over the whole growing period. These results show that soil N availability was sufficient to feed the vine during the whole growing period and that no inorganic N fertilisation was necessary, even in the grass covered soil. In this soil, water availability is probably the limiting factor when depressive effects are observed. On the long-term, it is necessary to manage the amount and quality of added organic matter since organic inputs may modify N availability and therefore vine behaviour, wine quality and environmental risks.; Nous avons étudié l'incidence du mode de couverture du sol (sol nu, apport d'écorces ou de composts, enherbe-ment) sur la fourniture en azote du sol de plusieurs vignobles expérimentaux en Champagne. La minéralisation nette d'azote par ces sols au cours de l'automne et de l'hiver va de 9 à 45 kg N ha-1 , sur une période de 118 à 182 jours. La vitesse de minéralisation correspondante, exprimée en « jours normalisés » (correspondant à une température constante de 15 °C et une humidité à la capacité au champ) est de 0.15 à 0.82 kg N ha-1 j-1 normalisé, tous traitements témoins confondus. La minéralisation n'est pas significativement affectée par les apports de produits organiques, sauf dans le cas des apports les plus anciens, les modifications étant fonction de la nature et des doses de produits organiques apportés.

Destiné à des conseillers et accompagnateurs d'agriculteurs, le guide pratique CEPviti est composé de trois parties : guide méthodologique expliquant la démarche, fiches supports pour conduire l’entretien, jeu de fiches techniques présentant les solutions techniques alternatives aux produits.