Understanding sweetness of dry wines: first evidence of astilbin isomers in red wines and quantitation in a one-century range of vintages

Vine growers face an increasing number of decisions, both tactical and strategic, in a context where available data and constraints are on the rise, such as resources, societal, environmental, climatic, and economic factors. This has led to a growing supply of decision support systems (DSS) and softwares to manage vineyards. Facing this new complexity, growers must now consider several options: giving up the use of DSS, using systems that are compatible with each other but may limit their options, or using a single system that may be too complex to use effectively. In this context, itk has expanded its Vintel® tool, which was originally designed for grapevine water status management (irrigation, inter-row, cover-crop, etc.), to include fertilization and disease management.

A terroir can be defined as a natural unit that is characterised by a specific agricultural potential, which is imparted by natural environmental features, and is reflected in the characteristics of the final product.

The paper presents the results of consistently developing studies carried out in 2022-2024 on the distribution of deuterium 2H(D) in intracellular water of grapes and wine products, taking into account the influence of natural, climatic and technogenic factors using high-resolution quantitative nuclear magnetic resonance spectroscopy 2H(D)-qNMR.

Annually, around 31.95 million tonnes of grapevine prunings are produced worldwide as agricultural waste.

In response to changes in their environment, grapevines regulate transpiration using various physiological mechanisms that alter conductance of water through the soil-plant-atmosphere continuum. Expressed as bulk stomatal conductance at the canopy scale, it varies diurnally in response to changes in vapor pressure deficit and net radiation, and over the season to changes in soil water deficits and hydraulic conductivity of both soil and plant. It is necessary to characterize the response of conductance to these variables to better model how vine transpiration also responds to these variables. Furthermore, to be relevant for vineyard-scale modeling, conductance is best characterized using data collected in a vineyard setting. Applying a crop canopy energy flux model developed by Shuttleworth and Wallace, bulk stomatal conductance was estimated using measurements of individual vine sap flow, temperature and humidity within the vine canopy, and estimates of net radiation absorbed by the vine canopy. These measurements were taken on several vines in a non-irrigated vineyard in Bordeaux France, using equipment that did not interfere with ongoing vineyard operations. An inverted Penman-Monteith equation was then used to calculate bulk stomatal conductance on 15-minute intervals from July to mid-September 2020. Time-series plots show significant diurnal variation and seasonal decreases in conductance, with overall values similar to those in the literature. Global sensitivity analysis using non-parametric regression found transpiration flux and vapor pressure deficit to be the most important input variables to the calculation of bulk stomatal conductance, with absorbed net radiation and bulk boundary layer conductance being much less important. Conversely, bulk stomatal conductance was one of the most important inputs when calculating vine transpiration, further emphasizing the need for characterizing its response to environmental changes for use in vineyard water use modeling.