Terroir 1996 banner
IVES 9 IVES Conference Series 9 Caratteristiche fisico-chimiche dei suoli coltivati a vite e loro influenza nella diffusione del mal dell’esca

Caratteristiche fisico-chimiche dei suoli coltivati a vite e loro influenza nella diffusione del mal dell’esca

Abstract

[English version below]

Il mal dell’esca é una malattia della vite della quale sono state studiate sintomatologia, eziologia, patogenesi ed epidemiologia. Essendo una malattia che colpisce soprattutto la parte epigea delle piante, le caratteristiche dei suoli non sono mai state considerate fra le responsabili della sua insorgenza e diffusione. In questo lavoro abbiamo studiato suoli di vigneti in cui il mal dell ‘esca présenta un ‘elevata incidenza e suoli di vigneti dove tale incidenza è scarsa o nulla. Le osservazioni morfologiche ed i risultati analitici indicano che i vigneti più danneggiati dalla malattia sono quelli i cui suoli presentano condizioni idromorfe a minima profondità, fra i 35 ed i 65 cm. Al contrario, i terreni dove l’incidenza é scarsa non presentano segni di idromorfia.
La difficoltà di percolazione, con conseguente instaurarsi di condizioni asfittiche, può essere imputata a due cause: 1) diminuzione di porosità totale negli orizzonti inferiori e 2) preponderante presenza di microporosità dovuta all’eccessivo contenuto di argilla e limo (dal 48 al 76%). Inoltre, l’argilla è costituita da minerali in grado di espandersi in presenza di acqua e, quindi, di rallentare ulteriormente il drenaggio del suolo. Al tri fattori che favoriscono la formazione di orizzonti asfittici sono: 1) i bassi tenori di carbonio organico non sufficienti a prevenire la migrazione dell ‘argilla; 2) la scarsa efficienza delle opere di drenaggio e 3) le lavorazioni meccaniche. Nei suoli ben drenati il contenuto di argilla e limo non supera il 45%, i minerali a reticolo espandibile sono presenti in tracce e, di conseguenza, non vi sono difficoltà di percolazione. Dalle nostre osservazioni risulta quindi che i vigneti maggiormente soggetti al mal dell ‘esca sono quelli che tendono a sviluppare condizioni di scarso drenaggio.

Studies have been conducted on the symptomatology, aetiology, pathogenesis and epidemic of the esca, a disease that affects grapes. Since Esca attacks mostly the above ground parts of the plants, the soil has not been considered relevant in the development and spreading of this disease. In this work we have investigated vineyard soils with a high incidence of esca, and others with a low or no incidence. Our morphological observations and analyses have shown that those vineyard affected by esca also manifest poorly drained conditions at a depth of about 35-65 cm. On the contrary the soils where the occurrence of the disease is less manifested are well drained.
The irnpeded drainage, with the attendant unoxy conditions, can be attributed to two causes: 1) a decreasing porosity in the lower horizons and 2) the prevailing micro porosity due to the high content of clay and silt (from 48 to 76%). Moreover, the clay is made of minerals that, once hydrated, tend to expand, further reducing the porosity and, thus, the drainage. Others factors that additionally cause a deterioration of the drainage are 1) the low organic matter content that prevent aggregation; 2) the inadequate drainage structures and 3) the continuous mechanical operations. In the well-drained soils the clay plus silt content is always less than 45%, the expandable minerals are presence in traces and, hence, there are not limitations to impede the drainage. We conclude that the vineyards more vulnerable to the esca are those painted on soils which tend to develop poorly drained conditions.

DOI:

Publication date: March 2, 2022

Issue: Terroir 1998

Type: Article

Authors

GIUSEPPE CORTI, FIORENZO C. UGOLINI, ROSANNA CUNIGLIO

Dipartimento di Scienza del Suolo e Nutrizione della Pianta
Piazzale delle Cascine, 15 – 50144 Firenze

Tags

IVES Conference Series | Terroir 1998

Citation

Related articles…

Mapping and tracking canopy size with VitiCanopy

Understanding vineyard variability to target management strategies, apply inputs efficiently and deliver consistent grape quality to the winery is essential. However, despite inherent vineyard variability, the majority are managed as if they are uniform. VitiCanopy is a simple, grower-friendly tool for precision/digital viticulture that allows users to collect and interpret objective spatial information about vineyard performance. After four years of field and market research, an upgraded VitiCanopy has been created to achieve a more streamlined, technology-assisted vine monitoring tool that provides users with a set of superior new features, which could significantly improve the way users monitor their grapevines. These new features include:
• New user interface
• User authentication
• Batch analysis of multiple images
• Ease the learning curve through enhanced help features
• Reporting via the creation of colour maps that will allow users to assess the spatial differences in canopies within a vineyard.
Use-case examples are presented to demonstrate the quantification and mapping of vineyard variability through objective canopy measurements, ground-truthing of remotely sensed measurements, monitoring of crop conditions, implementation of disease and water management decisions as well as creating a history of each site to forecast quality. This intelligent tool allows users to manage grapevines and make informed management choices to achieve the desired production targets and remain profitable.

Towards adaptation to climate change in Rioja: Quality evaluation of wines obtained from Grenache x Tempranillo selections

The wine sector is of great relevance and tradition in Mediterranean countries, however, it may be most susceptible to climate change. In recent years, wine production is facing changes worldwide, both at environmental as well as commercial levels, due to global warming and the shift in consumers’ preferences. Wine growers and wine makers are in search of solutions that allow to face these new challenges. One of the most promising initiatives in the long term is the introduction of new plant materials, specifically intraspecific hybridizations between premium varieties that may improve traditional germplasm in its adaptation to climate change. These inter-varietal crosses have the potential to generate quality wines, whilst maintaining the regional typicity, and constitute an attractive alternative for the consumer due to their sensory attributes. In this study, we have evaluated wines from 29 intraspecific Garnacha x Tempranillo hybrids in two different locations, with the aim to assess their oenological potential and sensory attributes. Thirteen of the selections were white and 16 were red. Microvinifications were conducted with two or three replications depending on grape availability. Conventional oenological parameters were determined for all wines. The sensory evaluation and hedonic scores were given by five experts. Red selections obtained higher quality scores than white ones. Among the white selections with higher quality scores, GT-41 Varea and GT-159 Varea outstand, due to their high total acidity and high malic acid content. Regarding red selections, GT-57 Varea and GT-57 UR were perceived as higher in quality, highlighted for their moderate alcoholic and high anthocyanin content. Our results indicate that intraspecific hybridization may be a powerful tool for adapting traditional cultivars to climate change in Rioja.

Aromatic maturity is a cornerstone of terroir expression in red wine

Harvesting grapes at adequate maturity is key to the production of high-quality red wines. Enologists and wine makers define several types of maturity, including technical maturity, phenolic maturity and aromatic maturity. Technical maturity and phenolic maturity are relatively well documented in the scientific literature, while articles on aromatic maturity are scarcer. This is surprising, because aromatic maturity is, without a doubt, the most important of the three in determining wine quality and typicity (including terroir expression). Optimal terroir expression can be obtained when the different types of maturity are reached at the same time, or within a short time frame. This is more likely to occur when the ripening takes place under mild temperatures, neither too cool, nor too hot. Aromatic expression in wine can be driven, from low to high maturity, by green, herbal, fresh fruit, ripe fruit, jammy fruit, candied fruit or cooked fruit aromas. Green and cooked fruit aromas are not desirable in red wines, while the levels of other aromatic compounds contribute to the typicity of the wine in relation to its origin. Wines produced in cool climates, or on cool soils in temperate climates, are likely to express herbal or fresh fruit aromas; while wines produced under warm climates, or on warm soils in temperate climates, may express ripe fruit, jammy fruit or candied fruit aromas. Growers can optimize terroir expression through their choice of grapevine variety. Early ripening varieties perform better in cool climates and late ripening varieties in warm climates. Additionally, maturity can be advanced or delayed by different canopy management practices or training systems.

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.

Second pruning as a strategy to delay maturation in cv. ‘Touriga nacional’ in the Portuguese Douro region

The advance in maturation of wine grapes is an important climate change risk related effect that could affect warm regions like Portuguese Douro Wine Region. Indeed, the climate analysis over the past years registered a decrease in the precipitation, significant higher average temperatures, and a more frequent occurrence of extreme weather events, including heat waves. In these conditions the length from anthesis until maturation is shortened and the uncoupling of technical and phenolic maturity results in berries with higher sugar concentration (and lower acidity), but lower anthocyanins, tannins, and total phenolic concentration, which produce unbalanced wines.
In this work, an innovative strategy of crop forcing, based on forcing vine regrowth after a second pruning of green shoots, was tested, aimed at delaying ripening until the temperature becomes lower and, therefore, preventing acidity loss and increasing anthocyanin-to-sugar ratio. The experiments were conducted in 2019 and 2020 in a commercial vineyard of ‘Touriga Nacional’ located in the Douro Region. Crop forcing was conducted 15 (CF1) to 30 (CF2) days after fruit set. Vines pruned with conventional methods were used as control (CF0). Results confirmed that fruit ripening was shifted from the hot season (August/September), until a cooler period (October through early-November). At harvest, grapevine berries from CF1 and CF2 presented lower pH and higher acidity, than control, with no significant differences in colour intensity and phenolic levels composition. Sugar content was lower in CF2-treated vines in both seasons. However, in CF-treated vines the number and size of clusters were significantly lower (up to 88% reduction) than in control plants. A metabolomics analysis of mature berries from CF-treated vines and control is underway. Crop forcing was indeed effective in producing a more balance berry composition but severely reduced grapevine yield,