The role of vine trunk height in delaying grape ripening: insights for viticultural adaptation strategies

As an essential element for grapevine development and yield, nitrogen is also involved in the winemaking process and largely affects wine composition. Grape must amino nitrogen deficiency affects the alcoholic fermentation kinetics and alters the development of wine aroma precursors. It is therefore essential to control and optimize nitrogen use efficiency by the plant to guarantee suitable grape nitrogen composition at harvest. Understanding the impact of environmental conditions and cultural practices on the plant nitrogen metabolism would allow us to better orientate our technical choices with the objective of quality and sustainability (less inputs, higher efficiency). This trial focuses on the impact of crop limitation – that is a common practice in European viticulture – on nitrogen distribution in the plant and particularly on grape nitrogen composition. A wide gradient of crop load was set up in a homogeneous plot of Chasselas (Vitis vinifera) in the experimental vineyard of Agroscope, Switzerland. Dry weight and nitrogen dynamics were monitored in the roots, trunk, canopy and grapes, during two consecutive years, using a 15N-labeling method. Grape amino nitrogen content was assessed in both years, at veraison and at harvest. The close relationship between fruits and roots in the maintenance of plant nitrogen balance was highlighted. Interestingly, grape nitrogen concentration remained unchanged regardless of crop load to the detriment of the growth and nitrogen content of the roots. Meanwhile, the size and the nitrogen concentration of the canopy were not affected. Leaf gas exchange rates were reduced in response to lower yield conditions, reducing carbon and nitrogen assimilation and increasing intrinsic water use efficiency. The must amino nitrogen profiles could be discriminated as a function of crop load. These findings demonstrate the impact of plant balance on grape nitrogen composition and contribute to the improvement of predictive models and sustainable cultural practices in perennial crops.

Sorting Chenin blanc is one of the most important white wine cultivars in South Africa. It has received a lot of attention and accolades in the past years and more research than ever is dedicated to this versatile cultivar. According to the Chenin blanc association of South Africa, there are three recognized dry wine styles, Fresh and Fruity (FF), Rich and Ripe Unwooded
(RRU), and Rich and Ripe Wooded (RRW). They are traditionally established with the aid of expert sensory evaluation, but the cost and the (subjective) human factor are aspects to be taken into account. A more objective and possibly robust way of assessing and attributing these styles can be the use of chemical analysis.

Le Dipartimento di Progettazione dell ‘Architettura del Politecnico di Milano et l’Istituto di Viticoltura della Facoltà d’Agraria di Piacenza dell’Università Cattolica del Sacra Cuore, ont elaboré une proposition pour réaliser, dans l’aire de colline de la province de Piacenza, un Parco Produttivo Agrovitivinicolo.

Les paysages participent à l’identité des vins de l’Hérault, avec une grande richesse de diversité. Leur observation, au travers des quatre saisons, s’appuie sur deux dimensions primordiales : la genèse de leur construction par l’homme et l’esthétique. L’hiver est la saison la plus favorable au décryptage de ce vignoble étagé, du littoral méditerranéen aux premières pentes du Massif Central; il permet de lire l’histoire des stratégies viticoles des vignerons. Les autres saisons sensibilisent plus à la beauté de vignobles dans des écrins de végétation typiquement méditerranéenne. La multiplicité des pratiques culturales et des cépages contribue à cet attrait. L’incitation au parcours, en toute saison, est très forte grâce au réseau des routes et des chemins de vigne.

Winegrowers must adapt more and more their viticultural practices in order to evolve toward a sustainable viticulture, to be competitive and to improve both the production methods and the quality and typicalness of wines. In this context, ‘Terroir’ studies in Loire Valley vineyards have allowed to build decision aid maps that can be used directly by growers to adjust their practices.