Viticultural potential assessment and its spatial delineation analysis in Goriška Brda viticultural area

Brettanomyces bruxellensis is found in various ecological niches, but particularly in fermentative processes: beer, kombucha, cider and wine. In the oenological sector, this yeast is undesirable, as it can produce ethyl phenols, thus altering wine quality. These compounds are characterized by stable or horse-sweat aromas, unpleasant for consumers.

AIM: Tawny Port wine is produced in the Douro Demarcated Region by blending several fortified wines in different aging stages. During the aging process in small wood barrels, the red wine color progressively develops into tawny, medium tawny, or light tawny.

There is an urgent need in viticulture to adopt alternative herbicide-free soil management strategies to mitigate climate change, increase biodiversity, reduce plant protection products and improve soil quality while minimizing detrimental effects on grapevine’s stress tolerance and fruit quality. To propose sustainable solutions, adapted to different pedoclimatic conditions in Switzerland, we developed a multidisciplinary 4-year project, started in 2020. Objectives of the project are to a) evaluate the impact of green covers (spontaneous flora, winter cover crop and permanent ground cover) on environmental and agronomic parameters and b) develop subsequently innovative strategies for different viticultural contexts of Switzerland. The project is divided into 3 phases: 1) diagnosis, 2) on-farm and 3) on-station experiments. Phase 1) consisted in an assessment of 30 commercial vineyards all over Switzerland, where growers already use different herbicide-free soil management strategies. The most promising practices identified in this exploratory phase will be replicated in commercial vineyards across Switzerland (“on-farm”) as well as in a classical randomized block design in an experimental plot (“on-station”). For phase 1), measurements consisted in evaluation of soil status (compaction, structure, roots development), soil microbial diversity (metagenomics), plant diversity and biomass, vine physiology (water stress, vigor, leaf nitrogen) and berry quality (acidity, sugar, available nitrogen). Interestingly, the permanent ground cover resulted in a higher Shannon index thus a higher biodiversity as compared to the other itineraries. The winter cover crop increased vine nitrogen and vigor while deteriorating soil quality, leaving the soil more exposed and compacted likely due to more frequent tillage. The spontaneous flora led to higher berry sugar accumulation, less nitrogen and higher malic acid concentration putatively due to a higher water retention of the flora in a particularly wet vintage. Phases 2) and 3) are required to confirm those tendencies, over the 3 next vintages and different climatic conditions.

Avec l’accroissement des surfaces viticoles conduites en Bio, la question de l’impact de la présence de résidus de cuivre (seul anti fongique autorisé dans l’UE dans ce cadre Règlementaire) sur le déroulement des fermentations et sur les qualités œnologiques et organoleptiques des vins s’est révélée de plus en plus cruciale.

In Castilla-La Mancha as other winegrowing regions, vineyards suffer the effects of the global climate warming. Severe spring and summer droughts are increasingly frequent, which concur with the phenological stages most susceptible to water and temperature stress. Under these conditions, irrigation use is required in order to ensure the vineyard growing sustainability. However water resources are increasingly limited, for this reason is required to choose cultivars displaying high water use efficiency.