Application of nitrogen forms such as nitrate, urea, and amino acids effects on leaf and berry physiology and wine quality

Downy mildew is one of the most important grapevine diseases, caused by the Oomycete Plasmopara viticola. The management of the disease in organic agriculture can require up to 15 copper applications per year. However, copper accumulates in the soil, is phytotoxic and is toxic for organisms living in the soil, its use has been restricted in European Union to maximum 28 kg in 7 years. Therefore, testing of alternatives with equal effectiveness is desirable. Among those, the natural biopolymer chitosan, obtained from crab shells, proved to be effective toward downy mildew in plot experiments. The aim of our trials was to extend chitosan applications in large scale experiments in different years, cultivars and environmental conditions.

The year-on-year rise in temperatures and the increase in extreme weather events due to climate change are already having an impact on agriculture. Among the perennial fruit species, grapevine is already negatively impacted by these events through an acceleration of its phenology, more damage from late frosts or through an increase in the sugar level of the berries (and therefore the alcoholic degree of the wine) and a decrease of acidity, impacting the wine quality. Sun’Agri, in partnership with INRAE, Chambre d’agriculture du Vaucluse, Chambre d’agriculture des Pyrénées-Orientales and IFV, developed a protection system based on dynamic agrivoltaics to protect grapevine. It consists of photovoltaic solar panels positioned above the crop, high enough not to impede the passage of agricultural machinery, and tiltable from +/- 90° to adjust the level of shading on the vineyard. These smart louvers, driven by artificial intelligence (physical models & plant growth models), are steered according to the plant’s needs and provide real climate protection.

The elemental composition (the ionome) of grape leaves is an important indicator of nutritional
health, but its genetic architecture has received limited scientific attention. In this study, we
analyzed the leaf ionome of 131 interspecific F1 hybrid progeny from a Vitis rupestris (♀) X Vitis
riparia (♂) cross. The progeny were replicated in New York, South Dakota, Southwest Missouri ad Central Missouri, and the concentration of 20 elements were measured in their leaves at
three different phenological stages during the growing season. In leaves collected at the apical node at anthesis, elemental concentrations correlated in a consistent manner (p < 0.05) across all four geographic locations. In subsequent phenological stages, elemental ratios in the apical-node leaves remained consistent across the South Dakota and New York sites, but not across the Missouri sites. In leaves collected at the basal and middle nodes, correlations varied greatly across all locations.

The metabolomics era started about 22 years ago, and wine was one of the first foodstuff subjects of analysis and investigation by this technique.

Context and purpose of the study. As other perennial crops grapevine is facing the challenges of climate changes. One of the major issues is global warming and variations of the water budget.