Does foliar fertilization with Seaweed improve the productivity and quality of ‘Merlot’ grape must?

Deciding to grow grapes in Oregon is complex issue due to our diverse geography, climate, and relatively short history of grape growing. For any potential grape grower, vineyard site selection is the single most important decision they will face.

Climate is the major factor influencing the dynamics of the vegetative cycle and can determine the timing of phenological periods. Knowledge of the phenology of varieties, their chronological duration, and thermal requirements, allows not only for the better management of interventions in the vineyard, but also to predict the varieties’ behaviour in a scenario of climate change, giving the wine producer the possibility of selecting the grape varieties that are best adapted to the climatic conditions of a certain terroir. In 2014, Symington Family Estates, Vinhos, established two grape variety libraries in two different places with distinctive climate conditions (Douro Superior, and Cima Corgo), with the commitment of contributing to a deeper agronomic and oenological understanding of some grape varieties, in hot climate conditions. In these research vineyards are represented local varieties that are important in the regional and national viticulture, but also others that have over time been forgotten — as well as five international reference cultivars. From 2017 to 2021, phenological observations have been made three times a week, following a defined protocol, to determine the average dates of budbreak, flowering and veraison. With the climate data of each location, the thermal requirements of each variety and the chronological duration of each phase have been calculated. During maturation, berry samples have been gathered weekly to study the dynamics of sugar accumulation, between other parameters. The data was analysed applying phenological and sugar accumulation models available in literature. The results obtained show significant differences between the varieties over several parameters, from the chronological duration and thermal requirements to complete the various stages of development, to the differences between the two locations, confirming the influence of the climate on phenology and the stages of maturation, in these specific conditions.

The vineyard of Bergerac, a guaranteed vintage, is situated in the mid-Lot valley, which has siliceous terraced rows on its hillsides, and on its bordering plateaux, composed of limestone and clay of the tertiary geological eras.

Infection of the grapes with Botrytis cinerea has a tremendous impact on the resulting crop yield and quality. Well-known problems that are associated with B. cinerea are specific off-flavors, poor filterability, and brownish color in white wines. The development of a B. cinerea infection strongly depends on weather conditions and is highly variable through different vintages. Typical control measures include defoliation and the use of fungicides, which involves high personnel and material costs. They also involve a great risk, especially since the effectiveness and time point of these treatments are difficult to predict.

Xinomavro is the most important indigenous red wine variety grown in Northern Greece. It participates in the production of several PGI wines in Macedonia while from 100% Xinomavro the PDO “Amyndeon” and “Naoussa” are produced. The viticultural area of Amyndeon lies in a plateau of 550 ‐700 m of altitude, in a semi‐continental climate with mostly deep sandy loamy soils derived from limestone and marl bedrocks while in Naoussa, Xinomavro is grown in a Mediterranean climate on more heavy textured soils, sandy clay loam to clay, derived from ophiolithic, limestone and marl bedrocks, in an altitude which varies from 150 to 400 m. Different soil, climate and viticultural technique interactions, result in great variability with respect to morphological, ampelographical and physiological characters of Xinomavro as well as in the characteristics of the wines produced.