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This article is published in cooperation with Terclim 2022 (XIVth International Terroir Congress and 2nd ClimWine Symposium), 3-8 July 2022, Bordeaux, France.; International audience; Climate influence on grapevine physiology is prevalent and this influence is expected to increase with climate change. Climate influence on grapevine physiology can vary depending on the terroir. A better understanding of these local terroir variations is likely to be achieved with analyses that use local data; i.e., farm/vineyard data. Thus, the challenge lies in exploiting farm data to enable grape growers to understand their own terroir and consequently adapt their practices to the local conditions. In such a context, this article proposes an analytical process to site-specifically study climate influence on grapevine physiology by focusing on time series of the weather data often contained in farm data sets. This article focuses on temperature and precipitation influence on yield in the form of a case study. The analytical process includes the Extended Growing Degree Days (eGDD) and the Bayesian functional Linear regression with Sparse Steps functions (BLiSS) methods in order to detect site-specific periods of strong climate influence on grapevine yield. It uses data from three commercial vineyards situated in the Bordeaux region (France), California (USA) and Israel. In general, the periods of climate influence on grapevine yield detected for the three vineyards identified the same stages of yield development, which have already been studied in the scientific literature. However, some vineyard differences were observed, including: i) different periods of influence associated with a given stage of yield development between the vineyards, ii) different influential weather variables between the three vineyards for a given period, and iii) differing duration of the period of influence associated with a given stage of yield development between the vineyards. These results show the potential of the proposed analytical process for analysing the time series of farm weather data in order to extract site-specific climate indicators of grapevine yield.

International audience; The spontaneous vegetation in vineyards is diverse and occupies an important spatial and temporal place. This vegetation is impacted by the different soil management practices and the pedoclimatic diversity of the vineyard terroirs. Its management is thought out according to the agronomic objectives of yield and quality, notably to limit competition with the vine. This management also responds to other ecological challenges: reduction in the use of herbicides, reduction in fossil fuel consumption, and the agro-ecological transition of winegrowing systems. In the "mixed" management method, which is often used, weed management in the inter-row is mainly based on mechanical weeding and/or grassing with mowing, while weeding in the row uses a chemical herbicide. In 2016, in France, inter-row weed control, whether partial or total, concerns 52% of the national vineyard area and varies greatly depending on the risk of drought and the density of plantation, which are decisive factors in the establishment and management of seeded cover. Among the many services, often linked to soil quality, potentially provided by these sown cover crops called service crops is the reduction of weeds by limiting their growth and development and inhibiting their germination. Finally, the management of spontaneous biodiversity within plots can satisfy other services such as the production of floral resources for pollinators or the production of biomass for grazing.; La flore des parcelles viticoles est diverse et occupe une place spatiale et temporelle importante dans les vignobles ; elle varie selon les pratiques d'entretien du sol et le pédoclimat. La gestion de cette flore est déterminée selon des objectifs de rendement et de qualité, et également des enjeux écologiques (herbicides, énergie fossile, et transition agroécologique). Aujourd'hui, la gestion des adventices repose majoritairement sur le désherbage mécanique et/ou l'enherbement avec tonte dans l'inter-rang, et le désherbage du rang utilise un herbicide chimique. En 2016, en France, l'enherbement sur l'inter-rang concerne la moitié du vignoble national et varie suivant le risque de sécheresse et la densité de plantation. Les cultures de services rendent de multiples services, dont la réduction des adventices. Enfin la gestion des adventices en parcelles viticoles peut fournir des services en relation avec la biodiversité (production de ressources florales pour les pollinisateurs ou de ressources fourragères).

International audience; The effect of nitrogen (N) nutrition on grapevine carbon (C) production, allocation and storage has been well-studied at the annual scale, but poorly addressed at a pluriannual timestep. Also, the quantification of N supply on C functioning raises interesting questions from a statistics-based methodological point of view. The aim of this study was to quantify, in an integrated conceptual framework, the pluriannual effect of N nutrition on potted Sauvignon blanc grapevine growth and storage over two consecutive years. The consequences of using destructive measurements to address this issue was investigated using a hierarchical Bayesian model.The segmentation of leaf area dynamics with a period of growth followed by a plateau showed that leaf area growth rate and the duration of growth were both positively impacted by the chlorophyll content of the leaves measured by SPAD index. However, the initial carbohydrates had the opposite effect on leaf growth, raising a distortion in the estimation of initial reserves. The carbon production per unit of global radiation was mostly linked to the leaf area dynamics. The allocation of dry matter was highly reliant on the phenological stage, but it was poorly impacted by the total dry matter. The present study highlighted the importance of using appropriate statistical methods to overcome uncertainties due to destructive measurements. The genericity of the statistical approach presented may encourage their implementation in other agronomy studies. Based on our results, a simple ecophysiological conceptual framework of grapevine pluriannual growth under various nitrogen supplies was built. This latter provides a relevant basis for a future model of grapevine C and N balances and responses to N fertilization.

International audience; Aim: Nitrogen is a major element conditioning grapevine growth, yield and aromatic profiles of berries and wines. Different tools can be used in order to detect differences in N status of the plant, including direct measurements of soil, plant nitrogen status (eg. petiole; must), or indirect observations of plant nutritional status such as leaf transmittance or reflectance (eg. SPAD; NDVI). However, the relationships between these indicators of nitrogen status and the overall plant functioning over vintages remain poorly known. The present study aimed at quantifying key vegetative and reproductive responses to plant nitrogen status over two successive seasons under different nitrogen supply levels. Methods and results: Potted plants of Sauvignon Blanc grafted onto SO4 were grown outdoors in 2017 and 2018 with no water limitation. Four mineral nitrogen fertilization levels (equivalent to 0 kg of N ha-1 or 0U, 20U, 40U, 80U) and one organic nitrogen fertilization level (40U) were imposed in 2017. These treatments were doubled in 2018 to increase the degree of nitrogen supply and consequently, the range of observed effects on plant growth and yield. Plant nitrogen status (SPAD) was monitored weekly during both growing cycles. Yield components were determined over the two seasons. Lastly, plant carbon status was addressed through dynamic measurement of plant development and photosynthesis, and destructive measurement of dry matter accumulation and carbon storage in annual and perennial organs at flowering, veraison and harvest. The SPAD values progressively decreased under lower N supply (0N) during the first year (from 31 to 16) and they were more than halved between the maximum and the minimum N treatments straight after budburst in year two (40 for 160N and 19 for 0N). Then, the differences in SPAD values among treatments were maintained up to harvest (2018). The gradient of N status resulted in a gradient of berry numbers per inflorescence (from 180 to 34 berries/inflorescence for 80N and 0N, respectively in 2018) and of individual berry dry matter at harvest (from 0.13 to 0.41 g for 160N and 0N, respectively in 2018). Quantitative relationships between N status and the relative reductions (% of reduction per %SPAD decrease) in terms of C gain (leaf area, photosynthesis), C growth (shoot, berry, trunk and root dry matter) and C storage (trunk and root) were fitted at flowering, veraison and harvest. The reduction in C gain under lower N supply was mainly related to the decrease in total leaf area before flowering (-1.64%). Although the photosynthesis rate tended to decrease under N deficiency over the season, it only poorly contributed to the reduction in C gain. The whole plant C growth was inhibited when N status decreased (-1.13% at harvest), due to the inhibition of shoot dry matter before veraison (-1.81%) and to a lower extent, to the lower dry matter in berries (-0.80%), trunks (-0.42%) and roots (-0.84%) at harvest. Part of the reduction in root dry matter was related to the lower starch reserves (-0.31%) at harvest. Interestingly, starch reserves tended to be higher under organic N supply than mineral N supply. Conclusion: The present results provided a general framework of carbon gain and use over time (within and between seasons) as impacted by N supply levels and form. Such a framework will be useful when building a model of the pluri-annual dynamics of carbon balance related to yield elaboration in grapevines.

National audience; In various regions of the world, climate change is predicted to induce modifications of the rainfall regime which, in turn, are to probably prompt changes in agricultural land-uses. In Central Cameroon, where cocoa cultivation is already carried out in sub-optimal rainfall areas, rainfall changes could threaten this currently crucial source of revenue. Yet, local cocoa growing systems include many complex agroforestry systems (AFS) that may not respond similarly to rainfall variability and drought than less diversified or monospecific cocoa plantations (Jagoret et al., 2017). The impact of climate change on such AFS and their resilience is debated in the recent literature (Abdulai et al., 2018) and needs to be investigated. Modelling could significantly contribute to the understanding of the main processes governing AFS functioning and be of great use to check for climate change effects on these processes. However, the relevance of simulated results greatly depends on model performance and modelling AFS remains today a scientific challenge. Therefore, few models are currently available. Yet, the WaNuLCAS model has proven to be efficient at modelling AFS particular crop-tree systems (Van Noordwijk and Lusiana, 1999) albeit it has not been extensively used for treetree systems. Furthermore, cocoa AFS often exhibit diverse structural parameters (functional type, height and age of cocoa or associated trees) which may greatly alter WaNuLCAS’ outputs (Coulibaly et al., 2014). We thus carried out a sensitivity analysis for evaluating the WaNuLCAS functioning and its ability to represent the change in water fluxes in cocoa AFS. WaNuLCAS was parameterised with soil and plant data collected in a previous study in Cameroon from 144 AFS distributed among three sites (Saj et al., 2017). The dataset contained information on the: i) density of cocoa and associated trees, ii) their DBH and basal area, iii) date of cocoa stand establishment, and iv) soil features. Weather data were retrieved from Nasa’s “TRMM” survey. We performed a sensitivity analysis of WaNuLCAS v4.01 to analyse the effects of structural parameters on water balance. The tested parameters were: i) density of trees, ii) soil characteristics, and iii) farmers’ management practices. Values of the parameters were changed up to 50% of the measured range. We analysed the water fluxes simulated, such as cocoa and associated trees transpiration, soil evaporation, drainage, and run-off. The work is on-going and final results shall be available for the WAF congress. Preliminary results indicate that WaLNuCAS is sensitive to rainfall variability and could be further used for analysing water fluxes of cocoa AFS under climate change scenarios. These results will allow determining the parameters and variables to be measured in priority in a future field experiment.

Agroforestry systems (AFS) are multi-species systems comprising cropped and associated spontaneous species, including trees. The species in AFS provide different levels of regulating, supporting and provisioning ecosystems services (ES). We assume that the provision of ES depends on the functional characteristics of all associated species and their spatial layout in the AFS, which we call here the “functional motif”. We propose the concept of Ecosystem Service Functional Motif (ESFM) defined as the smallest spatial unit that is relevant to understand the provision of all the targeted ES, at a given time. This ESFM is useful to determine the smallest scale at which data should be collected for relevant upscaling of AFS functioning. As a proof of the ESFM concept, we use it to describe existing AFS covering a wide range of species richness X spatial organisation. We show, for each AFS, the ESFM for various types of targeted (multiple) ES at various stages in the development of the system. We finally discuss the strengths and weaknesses of the ESFM concept for (i) analysing the AFS functioning, (ii) designing improved AFS according to ES targeted, and (iii) modelling such AFS.

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.

Ce projet, né du RMT Fertilisation et Environnement, vise à mettre au point un prototype d'outil de gestion de la fertilisation azotée pour les plantes pérennes, en se basant sur un outil déjà existant et innovant, utilisé sur les grandes cultures (AzoFert®) et basé sur la méthode du bilan. L'accent est mis sur 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 renseigner plusieurs catégories de données : localisation, sol, culture (itinéraire cultural, rendement visé). Une interface opérationnelle et conviviale a été développée, même si des améliorations restent à faire. Les résultats obtenus avec le prototype N-Pérennes sont encourageants en viticulture comparativement à des préconisations empiriques (50 % de préconisations correctes). En arboriculture, le manque de références expérimentales a induit un faible nombre de validations réalisées. Pour que le prototype devienne un outil opérationnel, il restera à réaliser à la fois du travail de programmation et de paramétrage, et une validation sur un plus grand nombre de situations, notamment en conditions réelles d’utilisation de l’outil. D’autres perspectives, élargissant l’objectif du prototype, sont également envisageables., This project, product of RMT “Fertilisation et Environnement”, aimed at developing a prototype of nitrogen fertilization management for perennial crops, by adapting an already existing and innovative tool used for annual crops (AzoFert®) and based on balance sheet method. The prototype is a computer program 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 improvements are still required. Validation results of prototype N-Pérennes are encouraging for vine growing compared with empirical recommendations (50 % of correct recommendations). For fruit growing, the lack of experimental 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.