Influence of soil characteristics on vine growth, plant nutrient levels and juice properties: a multi-year analysis

The sensory definition of the aging bouquet of red Bordeaux wines has been shown to be structured around seven main aromatic nuances: “undergrowth”, “spicy” “truffle”, “fresh red- and black-berry fruits”, “liquorice”, “mint”, and “toasted” (1). Some of these descriptors are also used to describe the aromatic notes of old Champagnes (2) suggesting common volatile compounds between these two types of wine.

The Institut Français De La Vigne Et Du Vin (IFV) is conducting many experiments on innovative winegrowing practices, which are emerging in companies in the sector, or which are still at the R&D stage for agricultural suppliers. The purpose of these practices may be to reduce environmental impact, to adapt vineyards to climate change, or to achieve other technical, economic or social aims. Whatever the objective, it is necessary to verify the relevance of these new practices, and in particular their environmental relevance, i.e. That at the very least, the changes in practices do not increase the environmental impact of the technical itineraries.

Background: Aroma compounds are important secondary metabolite in grapes and play important roles in the flavor and quality of grape berries and their wines. Vitis amurensis grape belongs to the East Asian Vitis spp., with excellent cold and disease resistance, and exhibits strong brewing potential. However, it has not been effectively utilized and there is no systematic research on the aroma compounds of V. amurensis grapes.
Methods: To provide sufficient experimental evidence for the characteristic aroma of V. amurensis grape, HS-SPME-GC/MS was used to identify the aroma compounds of five V. amurensis (‘Beiguohong’, ‘Beiguolan’, ‘Shuangfeng’, ‘Shuanghong’, ‘Shuangyou’) and three interspecific hybrids (‘Beibinghong’, ‘Xuelanhong’, ‘Zuoyouhong’) grapes in Zuojia and Ji’an. The grape berries were collected at harvest in 2020, 2021 and 2022.

As elsewhere, southwestern France vineyards face more recurrent summer heat waves these last years. Among the possibilities of adaptation to this climate changing parameter, the use of net shading is a technique that allow for limiting canopy exposure to radiations. In this trial, we tested net shading installed on one face of the canopy, on a north-south row-oriented plot of cv. Gros Manseng trained on VSP system in the PDO Pacherenc-du-Vic-Bilh. The purpose was to characterize the effects on the ambient canopy temperatures and radiations during the season and to observe the consequences on the composition of grapes and wines. Two sorts of net were used with two levels of obstruction (50% and 75%) of the photosynthesis active radiation (PAR). They have been installed on the west side of the canopy and compared to a netless control. Temperature and PAR sensors registered hourly data during the season. On specific summer day (hot and sunny) manual measurements took also place on bunches (temperature) and in different spots of the canopy (PAR). The results showed that, on clear days, the radiation is lowered by the shade nets respecting the supplier criteria. The effects on the ambient canopy temperature were inconstant on this plot when we observed the data from the global period of shading between fruit set and harvest. However, during hot days (>30°C), the temperature in the canopy was reduced during afternoon and the temperature of the bunch surface was reduced as well comparing to the control. A decrease of the maturity parameters of the berries, sugar and acidity, was also observed. Concerning the wine aromatic potential, no differences clearly appeared.

The study of the physiological behaviour of the grapevine (cv. Chasselas), and of plant hydraulics in particular, was conducted on various « terroirs » in the Canton of Vaud (Switzerland) between 2001 and 2003 by Agroscope Changins-Wädenswil ACW, in collaboration with the firm I. Letessier (SIGALES) in Grenoble and the Federal Polytechnic School of Lausanne (EPFL). An evaluation of the vine plant hydraulics was made by means of physiological indicators (leaf and stem water potentials, transpiration and leaf stomatal conductance, carbon isotope discrimination and a model of transpirable soil water), in relation to estimations of the soil water reservoir and climatic factors.