Sustainable yield management through fruitfulness and bunch architecture manipulation

Knowledge on the reflectance spectrum of soil is potentially useful since it carries information on soil chemical composition that can be used to the planning of agricultural practices. If compared with analytical methods such as conventional chemical analysis, reflectance measurement provides non-destructive, economic, near real-time data. This paper reports results from reflectance measurements performed by spectroradiometry on soils from two vineyards in south Brazil. The vineyards are close to each other, are on different geological formations, but were subjected to the same management. The objective was to detect spectral differences between the two areas, correlating these differences to variations in their chemical composition, to assess the technique’s potential to predict soil attributes from reflectance data.To that end, soil samples were collected from ten selected vine parcels. Chemical analysis yield data on concentration of twenty-one soil attributes, and spectroradiometry was performed on samples. Chemical differences significant to a 95% confidence level between the two studied areas were found for six soil attributes, and the average reflectance spectra were separated by this same level along most of the observed spectral domain. Correlations between soil reflectance and concentrations of soil attributes were looked for, and for ten soil traits it was possible to define wavelength domains were reflectance and concentrations are correlated to confidence levels from 95% to 99%. Partial Least Squares Regression (PLSR) analyses were performed comparing measured and predicted concentrations, and for fifteen out of 21 soil traits we found Pearson correlation coefficients r > 0.8. These preliminary results, which have to be validated, suggest that variations of concentration in the investigated soil attributes induce differences in reflectance that can be detected by spectroradiometry. Applications of these observations include the assessment of the chemical content of soils by spectroradiometry as a fast, low-cost alternative to chemical analytical methods.

Contribution Foam is the characteristic that differentiates sparkling wines from still wines, being the first sensory attribute that tasters and consumers perceive and that determines the final quality of sparkling wines [1]. The foaming properties mainly depend on the chemical composition of wines [2-3], and different factors involved in wine composition will have an effect on foam quality. In Spain, the sparkling wine market focuses on the production of white and rosé sparkling wine, with very low production of red sparkling wines. However, this type of wines is elaborated in countries like Australia, South-Africa, Argentina, Italy or Portugal, with a great acceptance by consumers. No studies on the foaming characteristics of red sparkling wines have been found.

Enzymatic browning[1] is an oxidation process that occurs in many foods that increases the brown colour[2]. This problem is especially harmful in the wine industry[3]. especially when the grapes are infected by grey rot since this fung release the oxidative enzyme laccase[4]. In the particular case of red wines, the presence of laccase implies the deterioration of the red colour and can even cause the precipitation of the coloring matter (oxidasic haze)[5].

Drought stress has a profound impact on grapevine productivity and significantly alters key quality-related traits of berries. Although research has been conducted on the effects of individual drought events, there is still a knowledge gap regarding the cumulative consequences of repeated exposure to water scarcity and the influence of the timing of stress imposition. To address this gap, a field experiment was conducted to investigate the impacts of repeated drought stress on yield, berry composition, and the phenolic profile of grape berries. The results indicate that yield is primarily influenced by pre-veraison water deficit. Although the number of clusters was only slightly reduced, a substantial decrease in berry size was observed, resulting in a notable reduction in overall yield.

In Portugal, and particularly in the Demarcated Region of Douro (DDR), wine production has a great tradition, producing the unique and worldwide famous Port wine as well as other remarkably good table wines. In this study the impact of projected climate change to wine production is analysed for the DDR. A statistical grapevine yield model (GYM) is developed using climate parameters as predictors.