Macrowine 2021
IVES 9 IVES Conference Series 9 Macrowine 9 Macrowine 2021 9 Grapevine diversity and viticultural practices for sustainable grape growing 9 Influence of early leaf removal on the yield and composition of the grape of three white varieties in the D.O.Ca.Rioja (Spain)

Influence of early leaf removal on the yield and composition of the grape of three white varieties in the D.O.Ca.Rioja (Spain)

Abstract

AIM: Defoliation is one of the green operations more used in viticulture, whose results can be very different depending on the variety and the moment of realization. Early leaf removal consists of the elimination of basal leaves on the shoots around pre-bloom stage, which limits fruit set and initial growth of the berry, leading to less compact clusters and less weight [1]. This practice allows to control the yield, improve the sanitary state and consequently the quality of the grape [2]. The objective of this research was to evaluate the influence of early leaf removal on the yield and composition in the grape of three white varieties: Tempranillo Blanco, Maturana Blanca and Garnacha Blanca.

METHODS: This study was conducted during the 2019 season, in a vineyard located in the D.O.Ca. Rioja (Spain). At the moment of harvest, the influence of early leaf removal on different yield components (unit production, number of bunches per vine, bunch weight, weight of 100 berries and number of berries per bunch) was determined. Prior to the harvest, 500 berries were sampled for each repetition and the must was extracted. Musts were physicochemically characterized by determining probable alcohol, pH, total acidity, tartaric acid, malic acid, potassium and total polyphenols.

RESULTS: The results obtained showed notable varietal differences. The early leaf removal gave rise to a decrease in the yield components, which only were significant in Tempranillo Blanco for the unit production, bunch weight and number of berries per bunch. Also, the effects of leaf removal on the composition of the grape were higher in Tempranillo Blanco. The total polyphenol content increased significantly in the three varieties. Maturana Blanca presented a significant rise in total acidity. On the contrary, Tempranillo Blanco showed a significant decrease, significantly increasing the pH and potassium. The probable alcohol showed a significant increase in Tempranillo Blanco and Garnacha Blanca.

CONCLUSIONS

To conclude, the influence of early leaf removal on the yield and composition of the grape is variable depending on the variety.

DOI:

Publication date: September 2, 2021

Issue: Macrowine 2021

Type: Article

Authors

Laura, Alti-Palacios

Instituto de Ciencias de la Vid y del Vino (Gobierno de La Rioja, CSIC, Universidad de La Rioja),Sara, GARCÍA, Instituto de Ciencias de la Vid y del Vino (Gobierno de La Rioja, CSIC, Universidad de La Rioja) Juana, MARTÍNEZ, Instituto de Ciencias de la Vid y del Vino (Gobierno de La Rioja, CSIC, Universidad de La Rioja)

Contact the author

Keywords

early leaf removal, yield components, chemical composition, white grape

Citation

Related articles…

A spatial explicit inventory of EU wine protected designation of origin to support decision making in a changing climate

Winemaking areas recognized as protected designations of origin (PDOs) shape important economic, environmental and cultural values that are tied to closely defined geographic locations. To preserve wine products and wine-growing practices adopted in different PDOs these areas are strictly regulated by legal specifications. However, quality viticulture is increasingly under pressure from climate change, which is altering the local conditions of many winegrowing areas. Therefore, maintaining traditional wine products will require the adoption of tailored adaptation strategies, including possible changes in the legal regulation of protected wines. To this end, it is necessary to have a comprehensive knowledge on PDOs including their extension, products and allowed practices. While there have been efforts to build databases that summarize the characteristics for individual wine PDO areas and to quantify the related effects of climate change, much information is still included only in the official documentation of the EU geographical indication register and has never been collected in a comprehensive manner. With this study we aim at filling this gap by building a spatial inventory of European wine PDOs that supports decision making in viticulture in the context of climate change. To map and characterize European wine PDOs, we analysed their legal documents and extracted relevant information useful for climate change adaptation. The output consists of a comprehensive geographical dataset that identifies the boundaries of all 1200 European wine PDOs at unprecedented spatial resolution and includes a set of legally binding regulations, such as authorized vine varieties, maximum yields and planting density. The inventory will allow researchers to analyse the impacts of climate change on European wine PDOs and support decision makers in developing tailored adaptation strategies. This includes, among others, the evaluation of new vineyard site selection, the expansion of cultivated varieties or the authorization of irrigation in vineyards.

Measurement of redox potential as a new analytical winegrowing tool

Excell laboratory has initiated the development of an analytical method based on electrochemistry to evaluate the ability of wines to undergo or resist to oxidative phenomena. Electrochemistry is a powerful tool to probe reactions involving electron transfers and offers possibility of real-time measurements. In that context, the laboratory has implemented electrochemical analysis to assess oxidation state of different wine matrices but also in order to evaluate oxidative or reduced character of leaf and soil. Initially, our laboratory focused on dosage of compounds involved in responses of plant stresses and we were also interested in microbiological activity of soils. These analyses were compared with the measurement of redox potential (Eh) and pH which are two fundamental variables involved in the modulation of plant metabolism. Indeed, the variation of redox states of the plant reflects its biological activity but also its capacity to absorb nutriments. The Eh-pH conditions mainly determine metabolic processes involved in soil and leaf and our goal is to determine if this combined analytical approach will be sufficiently precise to detect biological evolutions (plant health, parasitic attack…).

Heatwaves and grapevine yield in the Douro region, crop model simulations

Heatwaves or extreme heat events can be particularly harmful to agriculture. Grapevines grown in the Douro winemaking region are particularly exposed to this threat, due to the specificities of the already warm and dry climatic conditions. Furthermore, climate change simulations point to an increase in the frequency of occurrence of these extreme heat events, therefore posing a major challenge to winegrowers in the Mediterranean type climates. The current study focuses on the application of the STICS crop model to assess the potential impacts of heatwaves in grapevine yields over the Douro valley winemaking region. For this purpose, STICS was applied to grapevines using high-resolution weather, soil and terrain datasets over the Douro. To assess the impact of heatwaves, the weather dataset (1989-2005) was artificially modified, generating periods with anomalously high temperatures (+5 ºC), at certain onset dates and with specific durations (from 5 to 9 days). The model was run with this modified weather dataset and results were compared to the original unmodified runs. The results show that heatwaves can have a very strong impact on grapevine yields, strongly depending on the onset dates and duration of the heatwaves. The highest negative impacts may result in a decrease in the yield by up to -35% in some regions. Despite some uncertainties inherent to the current modelling assessment, the present study highlights the negative impacts of heatwaves on viticultural yields in the Douro region, which is critical information for stakeholders within the winemaking sector for planning suitable adaptation measures.

Climate ethnography and wine environmental futures

Globalisation and climate change have radically transformed world wine production upsetting the established order of wine ecologies. Ecological risks and the future of traditional agricultural systems are widely debated in anthropology, but very little is understood of the particular challenges posed by climate change to viticulture which is seen by many as the canary in the coalmine of global agriculture. Moreover, wine as a globalised embedded commodity provides a particularly telling example for the study of climate change having already attracted early scientific attention. Studies of climate change in viticulture have focused primarily on the production of systematic models of adaptation and vulnerability, while the human and cultural factors, which are key to adaptation and sustainable futures, are largely missing. Climate experts have been unanimous in recognising the urgent need for a better understanding of the complex dynamics that shape how climate change is experienced and responded to by human systems. Yet this call has not yet been addressed. Climate ethnography, coined by the anthropologist Susan Crate (2011), aims to bridge this growing disjuncture between climate science and everyday life through the exploration of the social meaning of climate change. It seeks to investigate the confrontation of its social salience in different locations and under different environmental guises (Goodman 2018: 340). By understanding how wine producers make sense of the world (and the environment) and act in it, it proposes to focus on the co-production of interdisciplinary knowledge by identifying and foreshadowing problems (Goodman 2018: 342; Goodman & Marshall 2018). It seeks to offer an original, transformative and contrasted perspective to climate change scenarios by investigating human agency -individual or collective- in all its social, political and cultural diversity. An anthropological approach founded on detailed ethnographies of wine production is ideally placed to address economic, social and cultural disruptions caused by the emergence of these new environmental challenges. Indeed, the community of experts in environmental change have recently called for research that will encompass the human dimension and for more broad-based, integrated through interdisciplinarity, useful knowledge (Castree & al 2014). My paper seeks to engage with climate ethnography and discuss what it brings to the study of wine environmental futures while exploring the limitations of the anthropological environmental approach.

Short-term relationships between climate and grapevine trunk diseases in southern French vineyards

[lwp_divi_breadcrumbs home_text="IVES" use_before_icon="on" before_icon="||divi||400" module_id="publication-ariane" _builder_version="4.19.4" _module_preset="default" module_text_align="center" module_font_size="16px" text_orientation="center"...