Please use this identifier to cite or link to this item: http://hdl.handle.net/2440/130225
Type: Conference paper
Title: Regulated deficit irrigation and crop load interaction effects on grape heterogeneity
Author: Armstrong, C.
Previtali, P.
Pagay, V.
Boss, P.
Jeffery, D.
Citation: Proceedings of the XIIIth International Terroir Congress, 2020 / pp.1-5
Publisher: IVES Conference Series
Publisher Place: online
Issue Date: 2020
Conference Name: International Terroir Congress (17 Nov 2020 - 18 Nov 2020 : Virtual online)
Statement of
Responsibility: 
Claire Armstrong, Pietro Previtali, Vinay Pagay, Paul Boss, David Jeffery
Abstract: Aim: To investigate the interaction effects between irrigation and crop load and the resulting impact on grape heterogeneity within a Geographical Indication in South Australia. Methods and Results: Cabernet Sauvignon grapes were sampled at the time of harvest from the Coonawarra Geographical Indication where full and sustained deficit irrigation and crop load manipulations were implemented as a 2 × 2 factorial block design. Grape heterogeneity was quantified for each treatment at three levels (bunch, vine and block) using berry density categories that were related to grape maturity. Furthermore, each density category was characterised in terms of total soluble solids, berry fresh weight, tannin content and tartaric and malic acid concentrations. Irrigation and crop load interaction effects on grape heterogeneity were observed for intra- cluster, vine, and between blocks. Conclusion: This research reveals the extent of heterogeneity existing in the vineyard at the time of harvest, and presents management techniques that may mitigate grape ripeness variation in the vineyard. Significance and Impact of the Study: Grape heterogeneity is an important consideration for the production of high quality red wine, as high proportions of under ripe and/or overripe fruit present at the time of harvest have been shown to negatively impact colour, mouthfeel, and varietal aroma of the wine. Furthermore, the presence of overripe/shrivelled grapes with excessive sugar concentrations can lead to increased ethanol in the wine. Previous research has acknowledged the impact that the three focal aspects of terroir – climate, soil and cultivar – have on grape composition, with the overarching effects of climate being highlighted. Vine water status and vine balance can conceivably mediate some of the influences of climate on grape composition, but there has been limited literature delving into the effects on grape heterogeneity. By investigating vineyard management techniques with a view to minimising grape heterogeneity, this research gives insight into the optimisation of grape production, especially in hotter climates that are more susceptible to producing overripe fruit.
Keywords: Vineyard management techniques; vineyard variation; grape composition; Cabernet Sauvignon; red wine quality
Rights: © IVES provides readers with immediate free access to all published content under Creative Commons Attribution (CC BY) license. (CC BY-NC 2.0)
RMID: 1000040642
Grant ID: http://purl.org/au-research/grants/arc/IC170100008
Published version: https://ives-openscience.eu/6927/
Appears in Collections:Agriculture, Food and Wine publications

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