The impact of leaf canopy management on eco-physiology, wood chemical properties and microbial communities in root, trunk and cordon of Riesling grapevines (Vitis vinifera L.)

The availability of water in the soil and the water status of the vineyard are proving to be determining factors for crop management in the current context of climatic variation

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.

Le Cabernet-Sauvignon est un cépage très répandu dans la région du Penedès (Espagne) où cette variété peut bien s’adapter et donne des produits de haute qualité.

AIM: Many research studies have analyzed the effect of polysaccharides in the aromatic composition of white wines.

La zonazione viticola rappresenta un importante strumento di indagine per valutare e interpretare le potenzialità produttive e qualitative di un territorio. Con l’obiettivo di studiare come l’ambiente influisca sulla qualità dell’uva nell’areale di Brisighella, sono stati monitorati, nelle annate 2007, 2008 e 2009, 14 vigneti per la varietà Albana e 38 per la varietà Sangiovese, rappresentativi di una area vitata di circa 1000 ha.