Terroir 1996 banner
IVES 9 IVES Conference Series 9 Influence de la nutrition potassique sur le manque d’acidité des vins issus du cépage Negrette

Influence de la nutrition potassique sur le manque d’acidité des vins issus du cépage Negrette

Abstract

Une baisse préoccupante de l’acidité des vins est observée dans beaucoup de régions viticoles, comme le Bordelais (Merlot), la Bourgogne (Pinot Noir), les Côtes-du-Rhône (Grenache) ou la Rioja (Tempranillo). Ce manque d’acidité est particulièrement marqué dans le vignoble Midi-Pyrénéen des Côtes du Frontonnais (Tournier, 1993). Or, l’acidité d’un vin est un des principaux facteurs de sa qualité, en effet, une faible acidité combinée à une structure tannique insuffisante entraîne une oxydation rapide des vins et les fait vieillir prématurément. De multiples travaux font état de la liaison étroite entre la faible acidité d’un moût ou d’un vin grande richesse en potassium (Boulton, 1980 ; Delas et al., 1989 ; Falcetti et al., 1993 ; Champagnol, 1988; Soyer et Molot, 1993).

D’autre part, la teneur en potassium des moûts est corrélée à celle des feuilles (Mattick, 1972 ; Champagnol, 1990) et une corrélation a été mise en évidence entre cette dernière et la fertilisation potassique (Morris et al., 1983 ; Champagnol, 1988, 1990 ; Soyer et Molot, 1993 ; Jourdan, 1993). Cependant, ces liaisons sont discutées par d’autres auteurs comme Dundon et al. (1984), Conradie et Saayman (1989) ou Matthews et al. (1993).
Pour contribuer à résoudre ce problème, nous avons choisi comme matériel d’étude la Négrette, cépage principal des Côtes du Frontonnais et cépage donnant des vins particulièrement peu acides.

Une double expérimentation a été mise en place. La première a été effectuée en culture hors-sol, sous serre. Elle a pour but de déterminer, grâce à l’application de solutions nutritives ayant des équilibres potassium-calcium différents, les relations existant entre les teneurs en potassium du milieu nutritif et celles des feuilles et des moûts, ainsi que leurs répercussions sur l’acidité des vins. La seconde est une expérimentation en champ qui a pour objectif d’étudier les interactions précédentes in situ. Le suivi de l’état nutritionnel de la vigne a été réalisé selon un protocole mis au point par Garcia et al. (1984) et Doux et al. (1985). La sélection des parcelles a été effectuée en s’inspirant de la méthode mise au point par Morlat et Asselin (1992).

DOI:

Publication date: March 25, 2022

Type: Poster

Issue: Terroir 1996

Authors

M. GARCIA (1), C. DAVEREDE (1), P. GALLEGO (1), D. VIGNES (2), J.L. FAVAREL (3), F. DEDIEU (4)

(1) Institut National Polytechnique-ENSAT, 145 av de Muret 31076 Toulouse
(2) CESBIO, 18 av Edouard Belin 31055 Toulouse
(3) Institut Technique de la Vigne et du vin-Gaillac, 52 Place Jean Moulin 81300 Gaillac
(4) Faculté de pharmacie, Chemin des Maraîchers 31062 Toulouse Cédex

Tags

IVES Conference Series | Terroir 1996

Citation

Related articles…

Assessment of the impact of actions in the vineyard and its surrounding environment on biodiversity in Rioja Alavesa (Spain)

Traditional viticulture areas have experienced in the last decades an intensification of field practices, linked to an increased use of fertilisers and phytosanitary products, and to a more intensive mechanization and uniformization of the landscape. This change in management has sometimes led to higher rates of soil erosion andloss of soil structure, fertility decline, groundwater contamination, and to an increased pressure of pests and diseases. Additionally, intensification usually leads to a simplification of landscapes, of particular concern in prestigious wine grape regions where the economical revenue encourages the conversion of land use from natural habitats to high value wine grape production. To revert this trend, it is necessary that growers implement actions that promote biodiversity in their vineyards. The aim of this study is to assess the impact of the implementation of cover crops, vegetational corridors, dry stone walls and vineyard biodiversity hotspots estimated through the study of arthropods. The work has been carried out in four vineyards in Rioja Alavesa belonging to Ostatu winery, where these infrastructures were implemented in 2020. The presence and diversity of arthropods was studied by capturing them at different times in the season and at different distances from the infrastructure using pit-fall traps in the soil and yellow, white and blue chromatic traps at the canopy level. This is a preliminary study in which all adult insects were sorted to the taxonomic level of order and Coleoptera were classified to morphospecies. The results obtained show that there is a relationship between the basic characteristics of the vineyard and the arthropods captured, with a positive effect, although also dependent on the vineyard, of the presence of infrastructure.

Long-term drought resilience of traditional red grapevine varieties from a semi-arid region

In recent decades, the scarcity of water resources in agriculture in certain areas has been aggravated by climate change, which has caused an increase in temperatures, changes in rainfall patterns, as well as an increase in the frequency of extreme phenomena such as droughts and heat waves. Although the vine is considered a drought-tolerant specie, it has to satisfy important water requirements to complete its cycle, which coincides with the hottest and driest months. Achieving sustainable viticulture in this scenario requires high levels of efficiency in the use of water, a scarce resource whose use is expected to be severely restricted in the near future. In this regard, the use of drought-tolerant varieties that are able to maintain grape yield and quality could be an effective strategy to face this change. During three consecutive seasons (2018-2020) the behavior in rainfed regime of 13 traditional red grapevine varieties of the Spain central region was studied. These varieties were cultivated in a collection at Centro de Investigación de la Vid y el Vino de Castilla-La Mancha (IVICAM-IRIAF) located in Tomelloso (Castilla-La Mancha, Spain). Yield components (yield, mean bunch and berry weight, pruning weight), physicochemical parameters of the musts (brix degree, total acidity, pH) and some physiological parameters related with water stress during ripening period (δ13C, δ18O) were analysed. The application of different statistical techniques to the results showed the existence of significant differences between varieties in their response to stressful conditions. A few varieties highlighted for their high ability to adapt to drought, being able to maintain high yields due to their efficiency in the use of water. In addition, it was possible quantify to what extent climate can be a determinant in the δ18O of musts under severe water stress conditions.

Climate change projections to support the transition to climate-smart viticulture

The Earth’s system is undergoing major changes through a wide range of spatial and temporal scales as a response to growing anthropogenic radiative forcing, which is pushing the whole system far beyond its natural variability. Sources of greenhouse gases largely exceed their sinks, thus leading to a strengthened greenhouse effect. More energy is thereby being supplied to the system, with inevitable shifts in climatic patterns and weather regimes. Over the last decades, these modifications have been manifested in the full statistical distributions of the atmospheric variables, with dramatic changes in the frequency and intensity of extremes. Natural hazards, such as severe droughts, floods, forest fires, or heatwaves, are being triggered by extreme atmospheric events worldwide, thus threatening human activities. Viticultculture is not only exposed to changing climates but is also highly vulnerable, as grapevine phenology and physiological development are strongly controlled by atmospheric conditions. Therefore, the assessment of climate change projections for a given region is critical for climate change adaptation and risk reduction in viticulture. By adopting timely and suitable measures, the future sustainability and resiliency of the sector can be fostered. Climate-grapevine chain modelling is an essential tool for better planning and management. However, the accuracy of the resulting projections is limited by many uncertainties that must be duly taken into account when transferring knowledge to stakeholders and decision-makers. Climate-smart viticulture will comprise ensembles of locally tuned strategies, envisioning both adaptation and mitigation, assisted by emerging technologies and decision-support systems.

Influence of agronomic practices in soil water content in mid-mountain vineyards

In the context of LIFE project MIDMACC (LIFE18 CCA/ES/001099), several pilots have been installed in vineyards in mid mountain areas of Catalonia (NE Spain) to test well stablished agronomic practices to increase the adaptation of Mediterranean mid mountain to climate change. Soil water content (SWC) at three different depths (15, 30 and 45cm) was measured in continuum from August 2020. One pilot (WC) included a well-established green cover (GC), a new GC (NC) and a conventional soil management (CM, tilling+herbicides). NC presented an intermediate state between WC and CM, responding similarly to CM in autumn but quickly reaching similar SWC to WC, then following the same evolution till next spring, with CM presenting lower values along autumn and winter. Then vegetation activation decreased SWC in all plots, (much slower in CM, lacking GC). Sensibility to spring rains is again intermediate for NC, which joins SWC evolution of CM by the end of spring till next autumn. It is expected that NC will resemble WC more and more as its GC develops. In the pilot combining vine training (VSP vs Gobelet) and hillside management (slope vs terrace), no clear pattern could be related with these conditions. However, both terraces seem to be more sensitive to spring rains. A third pilot included new vineyards (7 and 1 year old). In the new vineyard (N), higher canopy development, a spontaneous green cover and row straw resulted in a slower SWC dynamic, not so sensitive to rains but conserving more soil water in spring and most of summer, even with presumably a higher water extraction by vines. In the newest vineyard (VN) the deepest sensor is still sensitive to rain events all over the year and SWC is always highest at this depth, revealing small water capture by vines.

Spatial determination of areas in the Western Balkans region favorable for organic production

In problematic conditions for production of grapes and wine caused by the COVID-19 pandemic and the resulting occurrence of wine surpluses, producers are increasingly turning to the innovative viticulture and winemaking of products that are more appealing to the market and the consumers. On the other hand, consumption of the food safety or organic products, and therefore of organic grapes and wine, is increasingly common in the world, in particular in Europe. The Regional Rural Development Standing Working Group (SWG RRD), as a regional intergovernmental organization gathers actors in the viticulture and winemaking sector from states and territories of the Western Balkans (South-East Europe) in the Expert Working Group for Wine, with the aim of improving viticulture and winemaking in this region through joint activities. In accordance with the aforementioned, the SWG RRD is working on advancing organic production of grapes and wine, and on recognition of specificities of the terroir of wine-growing areas in Western Balkans. In addition, as part of the project “Facilitation of Exchange and Advice on Wine Regulations in Western Balkan Countries” helmed by the German Federal Ministry of Food and Agriculture, in addition to harmonization of relevant legislation with EU regulations, efforts are being invested towards recognition of organic wines. Within activities and project implemented by this organization, expert analyses and scientific research of the terroir of Western Balkans were carried out, and some of the results are presented in this paper.