Macrowine 2021
IVES 9 IVES Conference Series 9 Macrowine 9 Macrowine 2021 9 Grapevine diversity and viticultural practices for sustainable grape growing 9 Application to grapevine leaves of different doses of urea at two phenology stage: effect on the aromatic composition of red wine

Application to grapevine leaves of different doses of urea at two phenology stage: effect on the aromatic composition of red wine

Abstract

AIM: This research aimed to study the effect and efficiency of foliar application of urea on the aromatic composition of red wines elaborated from Tempranillo grapes.

METHODS: This study was carried out in 2018 and 2019. The plot was located in the North of Spain. The grapes were Vitis vinifera L. Tempranillo and grafted on 110 Richter rootstocks. The vine-training system was gobelet and leave twelve buds per vine. The plot was not fertilized and not irrigated, during the two study seasons. The treatments were: control (C), whose plants were sprayed with water; and three different doses of urea: plants were sprayed with 3 kg N/ha (U3), 6 kg N/ha (U6) and 9 kg N/ha (U9). The treatments were performed at two different phenological states, pre-veraison (Pre) and veraison (Ver). Also, each treatment was repeated one week later. The applications were carried out early in the morning to maximize the absorption of urea. Treatments were organized in a complete randomised block design and were performed in triplicate. The grapes were picked at optimum maturity and then, were destemmed and crushed. Each treatment was fermented on stainless steel tanks. The alcoholic fermentation was started by inoculating with commercial Saccharomyces cerevisiae strain Uvaferm VRB and the malolactic fermentation was inoculated with commercial Oenococcus oeni strain Lalvin SILKA. After malolactic fermentation, the aliquots of each wine were frozen to determine their volatile composition. Analysis of volatile compounds from the wine was carried out by gas chromatography–mass spectrometry (GC-MS) [1]. Quantification of compounds was performed with an internal standard method. Finally, the results were studied statistically by analysis of variance (ANOVA).

RESULTS: In the two seasons, the higher alcohols were the most abundant fermentative compounds found in wines, highlighting isoamyl alcohols and 2-phenylethanol. In 2018, the content of all volatile compounds was increased by the treatment U3-Pre. Nevertheless, the treatments carried out in veraison had different effects. The acetate esters and the sum of ethyl hexanoate, octanoate and decanoate were increased by U9 treatment. Also, U6 increased the concentration of total ethyl esters, total esters, and other volatile compounds. However, the higher alcohols were lower in the all treated wines. In 2019, the wines elaborated from grapes treated with U3-Pre presented a higher concentration of aromatic compounds. Moreover, U3-Ver improved the content of alcohols, acetate esters, the sum of ethyl hexanoate, octanoate and decanoate, and total esters; while, the other volatile compounds were risen by U9-Ver.

CONCLUSIONS

In the two seasons, the lowest dose of urea (U3) applied in pre-veraison improved the aromatic composition of Tempranillo wine.

DOI:

Publication date: September 2, 2021

Issue: Macrowine 2021

Type: Article

Authors

Rebeca Murillo-Peña

Institute of Grapevine and Wine Sciences (Spanish National Research Council, Government of La Rioja, University of La Rioja) ,Teresa, GARDE-CERDÁN, Institute of Grapevine and Wine Sciences (Spanish National Research Council, Government of La Rioja, University of La Rioja)  José María, MARTÍNEZ-VIDAURRE, Institute of Grapevine and Wine Sciences (Spanish National Research Council, Government of La Rioja, University of La Rioja)

Contact the author

Keywords

pre-veraison, veraison, tempranillo, volatile compounds, wine, urea, foliar application

Citation

Related articles…

Terroir analysis and its complexity

Terroir is not only a geographical site, but it is a more complex concept able to express the “collective knowledge of the interactions” between the environment and the vines mediated through human action and “providing distinctive characteristics” to the final product (OIV 2010). It is often treated and accepted as a “black box”, in which the relationships between wine and its origin have not been clearly explained. Nevertheless, it is well known that terroir expression is strongly dependent on the physical environment, and in particular on the interaction between soil-plant and atmosphere system, which influences the grapevine responses, grapes composition and wine quality. The Terroir studying and mapping are based on viticultural zoning procedures, obtained with different levels of know-how, at different spatial and temporal scales, empiricism and complexity in the description of involved bio-physical processes, and integrating or not the multidisciplinary nature of the terroir. The scientific understanding of the mechanisms ruling both the vineyard variability and the quality of grapes is one of the most important scientific focuses of terroir research. In fact, this know-how is crucial for supporting the analysis of climate change impacts on terroir resilience, identifying new promised lands for viticulture, and driving vineyard management toward a target oenological goal. In this contribution, an overview of the last findings in terroir studies and approaches will be shown with special attention to the terroir resilience analysis to climate change, facing the use and abuse of terroir concept and new technology able to support it and identifying the terroir zones.

Terroir traceability in grapes, musts and wine: results of research on Gewürztraminer and Sauvignon Blanc grape varieties in northern Italy

In the study of terroir, a separate analysis of its many component factors can be of great help in accurately identifying a vineyard’s natural elements that impact wine quality and typicity. This research used a dedicated pluri-disciplinary approach to investigate the ecological characteristics, including geology and geographical features, of 14 vineyards that produce Gewürztraminer and Sauvignon Blanc cultivars in the alpine Alto Adige DOC wine region. Both the geopedological method using Vineyards Geological Identity (VGI) and the new Solar Radiaton Identity (SRI) topoclimatic classification method were used to provide analytical measurements and qualitative/quantitative characterisations. In addition, wide-ranging targeted and untargeted oenological and chemical analyses were carried out on grapes, musts and wines to correlate the soils’ geomineral and physical conditions with the biochemical properties of their fruits and wines. The research identified strong correlations between vineyard geo-identity and wine biofingerprint, confirming a mineral traceability of strontium rubidium ratio and some minerals distinctive to the local geology, such as K, Ca, Ag, Ba and Mn.  The study also discovered that particular geomineral and physical soil conditions of the studied vineyards are related to the different amount of amino acids, primary varietal aromas and polyphenols found in grapes, musts and wines. The research confirmed that winemaking technologies support oenological quality, although in some cases, human practices can overpower certain characteristic elements in wine, erasing the typical imprint left by the vineyards’ natural terroir, which becomes less traceable. Terroir abiotic ecological factors and vineyard identity can be classified in detail using the new VGI and SRI analysis methods to discover interrelationships between geo-pedological and topoclimatic conditions that impact wine quality. These methods are also helpful in identifying which ecological elements are exclusive to a particular vineyard or wine sub-region.

Making sense of available information for climate change adaptation and building resilience into wine production systems across the world

Effects of climate change on viticulture systems and winemaking processes are being felt across the world. The IPCC 6thAssessment Report concluded widespread and rapid changes have occurred, the scale of recent changes being unprecedented over many centuries to many thousands of years. These changes will continue under all emission scenarios considered, including increases in frequency and intensity of hot extremes, heatwaves, heavy precipitation and droughts. Wine companies need tools and models allowing to peer into the future and identify the moment for intervention and measures for mitigation and/or avoidance. Previously, we presented conceptual guidelines for a 5-stage framework for defining adaptation strategies for wine businesses. That framework allows for direct comparison of different solutions to mitigate perceived climate change risks. Recent global climatic evolution and multiple reports of severe events since then (smoke taint, heatwave and droughts, frost, hail and floods, rising sea levels) imply urgency in providing effective tools to tackle the multiple perceived risks. A coordinated drive towards a higher level of resilience is therefore required. Recent publications such as the Australian Wine Future Climate Atlas and results from projects such as H2020 MED-GOLD inform on expected climate change impacts to the wine sector, foreseeing the climate to expect at regional and vineyard scale in coming decades. We present examples of practical application of the Climate Change Adaptation Framework (CCAF) to impacts affecting wine production in two wine regions: Barossa (Australia) and Douro (Portugal). We demonstrate feasibility of the framework for climate adaptation from available data and tools to estimate historical climate-induced profitability loss, to project it in the future and to identify critical moments when disruptions may occur if timely measures are not implemented. Finally, we discuss adaptation measures and respective timeframes for successful mitigation of disruptive risk while enhancing resilience of wine systems.

Simulating climate change impact on viticultural systems in historical and emergent vineyards

Global climate change affects regional climates and hold implications for wine growing regions worldwide. Although winegrowers are constantly adapting to internal and external factors, it seems relevant to develop tools, which will allow them to better define actual and future agro-climatic potentials. Within this context, we develop a modelling approach, able to simulate the impact of environmental conditions and constraints on vine behaviour and to highlight potential adaptation strategies according to different climate change scenarios. Our modeling approach, named SEVE (Simulating Environmental impacts on Viticultural Ecosystems), provides a generic modeling framework for simulating grapevine growth and berry ripening under different conditions and constraints (slope, aspect, soil type, climate variability…) as well as production strategies and adaptation rules according to climate change scenarios. Each activity is represented by an autonomous agent able to react and adapt its reaction to the variability of environmental constraints. Using this model, we have recently analyzed the evolution of vineyards’ exposure to climatic risks (frost, pathogen risk, heat wave) and the adaptation strategies potentially implemented by the winegrowers. This approach, implemented for two climate change scenarios, has been initiated in France on traditional (Loire Valley) and emerging (Brittany) vineyards. The objective is to identify the time horizons of adaptations and new opportunities in these two regions. Carried out in collaboration with wine growers, this approach aims to better understand the variability of climate change impacts at local scale in the medium and long term.

Variety and climatic effects on quality scores in the Western US winegrowing regions

Wine quality is strongly linked to climate. Quality scores are often driven by climate variation across different winegrowing regions and years, but also influenced by other aspects of terroir, including variety. While recent work has looked at the relationship between quality scores and climate across many European regions, less work has examined New World winegrowing regions. Here we used scores from three major rating systems (Wine Advocate, Wine Enthusiast and Wine Spectator) combined with daily climate and phenology data to understand what drives variation across wine quality scores in major regions of the Western US, including regions in California, Oregon and Washington. We examined effects of variety, region, and in what phenological period climate was most predictive of quality. As in other studies, we found climate, based mainly on growing degree day (GDD) models, was generally associated with quality—with higher GDD associated with higher scores—but variety and region also had strong effects. Effects of region were generally stronger than variety. Certain varieties received the highest scores in only some areas, while other varieties (e.g., Merlot) generally scored lower across regions. Across phenological stages, GDD during budbreak was often most strongly associated with quality. Our results support other studies that warmer periods generally drive high quality wines, but highlight how much region and variety drive variation in scores outside of climate.