Terroir 2004 banner
IVES 9 IVES Conference Series 9 The role of soil water holding capacity and plant water relations in zone/terroir expression

The role of soil water holding capacity and plant water relations in zone/terroir expression

Abstract

The spatial variability in soil type and depth and water holding capacity is very high in many viticultural regions of the world. Differences in rooting depths and water extraction profiles and their seasonal dynamics add additional variability and it is extremely difficult to deduct direct causal relationships between these factors and fruit composition even within small units of climatic zones, and much less so over larger climatic trans-sects. The influence of water status on grape composition has been studied intensively for many years, yet indirect effects caused by changes in plant water status have been largely neglected. For example, vineyard sites with limited water supply will be more prone to early leaf drop causing substantial changes in the light environment of the fruit, which in itself will change fruit temperature. Additionally, there is almost certainly a different link between plant water status and fruit and wine composition for red and white cultivars and within each respective group between varieties of different geographic origin. Another unresolved problem is the coupling of soil to plant water status. Many plant water status indicators such as stem, or midday or pre-dawn (ΨPD) leaf water potential are difficult to link to quantitative soil water data. We have recently started to use the concept of total transpirable soil water (TTSW) and the fraction thereof (FTSW), originally proposed for herbaceous plants, to evaluate the coupling between soil water availability and plant water status measurements for contrasting vineyard sites. Even for soil water holding capacities over the root profiles between 380 and 100 L/m2, and a TTSW varying from 50 to 175 L/m2, respectively, we found a single common relationship between ΨPD and FTSW for all vineyards, irrespective of water extraction profiles and canopy systems (Gruber and Schultz 2004 in press). This relationship has also been proven stable across different wine regions in Europe. This system may provide a platform to better link quality parameters to plant and soil water status. Some recent results also suggest that indirect effects of changes in water supply may be more important than previously thought for fruit composition. These effects seem not restricted to changes in canopy microclimate or co-limiting factors such as nitrogen, but seem to extend to substances influencing micronutrient metabolism of yeasts, which may alter aromatic expression. It is clear and has been proven many times that water relations are important in quality formation and in the expression of terroir characters, yet it is still difficult to provide conclusive linkages between all the involved parameters.

DOI:

Publication date: January 12, 2022

Issue: Terroir 2004

Type: Article

Authors

H. R. Schultz (1,2), Bernd Gruber (1)

(1) Institut für Weinbau und Rebenzüchtung, Forschungsanstalt Geisenheim, Germany
(2) Fachbereich Weinbau und Getränketechnologie, Fachhochschule Wiesbaden, von Lade Str. 1, D-65366 Geisenheim, Germany

Contact the author

Tags

IVES Conference Series | Terroir 2004

Citation

Related articles…

What triggers the decision to ripen 

The decision for grape berries to ripen involves a complex interplay of genetic regulation and environmental cues. This review explores the molecular mechanisms underlying the transition from vegetative growth to ripening, focusing on transcriptomic studies and the role of the NAC gene family. Transcriptomic analyses reveal a significant rearrangement of gene expression patterns during this transition, with up-regulation of ripening-related genes and down-regulation of those associated with vegetative growth. A molecular phenology scale providing a high-precision map of berry transcriptomic development, indicates that key molecular changes occur well before the onset of ripening.

Detection of spider mite using artificial intelligence in digital viticulture

Aim: Pests have a high impact on yield and grape quality in viticulture. An objective and rapid detection of pests under field conditions is needed. New sensing technologies and artificial intelligence could be used for pests detection in digital viticulture. The aim of this work was to apply computer vision and deep learning techniques for automatic detection of spider mite symptoms in grapevine under field conditions. 

The potential of multispectral/hyperspectral technologies for early detection of “flavescence dorée” in a Portuguese vineyard

“Flavescence dorée” (FD) is a grapevine quarantine disease associated with phytoplasmas and transmitted to healthy plants by insect vectors, mainly Scaphoideus titanus. Infected plants usually develop symptoms of stunted growth, unripe cane wood, leaf rolling, leaf yellowing or reddening, and shrivelled berries. Since plants can remain symptomless up to four years, they may act as reservoirs of FD contributing to the spread of the disease. So far, conventional management strategies rely mainly on the insecticide treatments, uprooting of infected plants and use of phytoplasma-free propagation material. However, these strategies are costly and could have undesirable environmental impacts. Thus, the development of sustainable and noninvasive approaches for early detection of FD and its management are of great importance to reduce disease spread and select the best cultural practices and treatments. The present study aimed to evaluate if multispectral/hyperspectral technologies can be used to detect FD before the appearance of the first symptoms and if infected grapevines display a spectral imaging fingerprint. To that end, physiological parameters (leaf area, chlorophyll content and photosynthetic rate) were collected in concomitance to the measurements of plant reflectance (using both a portable apparatus and a remote sensing drone). Measurements were performed in two leaves of 8 healthy and 8 FD-infected grapevines, at four timepoints: before the development of disease symptoms (21st June); and after symptoms appearance (ii) at veraison (2nd August); at post-veraison (11th September); and at harvest (25th September). At all timepoints, FD infected plants revealed a significant decrease in the studied physiological parameters, with a positive correlation with drone imaging data and portable apparatus analyses. Moreover, spectra of either drone imaging and portable apparatus showed clear differences between healthy and FD-infected grapevines, validating multispectral/ hyperspectral technology as a potential tool for the early detection of FD or other grapevine-associated diseases.

Impact of acidification by fumaric acid at vatting on Cabernet-Sauvignon wine during winemaking

Acidity of grape berries is lowered due to climate changes (1), resulting in musts and wines with higher pHs. These higher pHs induce microbiological instability

Conservation: the best valorisation strategy for wine growing areas

Terroir encompasses many elements, including environment, grapes and human inputs that together contribute to the final wine quality of a certain wine growing area.