Wines are made in the vineyard, which is especially true for premium quality wines. A study by Orley Ashenfelter from Princeton University revealed that the quality of the top Bordeaux vintages is predicted by the weather during the grape growing season. The price follows quality, and as every winegrower tends to maximize profits, it is crucial to work on producing premium quality wines while lowering input costs vintage by vintage. But in a constantly changing climate, that’s easier said than done.

Winegrowers can’t change the vine’s environmental conditions, however, they can get a better knowledge of a particular vineyard site and vintage weather specifics with the help of new and improved precision viticulture technology. Based on gathered insights, they can adjust the viticulture, as well as enological practices, to produce the best quality wine in the given vintage.

Apart from the weather, several other factors affect the production of premium quality grapes, thus many are within the control of the grower, under given climatic and soil conditions. Each of them individually affects the vine, but they are interrelated and thus together influence the quality of the grape. The figure below shows how soil, climate, and vineyard management directly or indirectly affect fruit composition.

Direct and indirect effects of soil, climate, and vineyard management to fruit composition

Figure (Weldon, 2003): A conceptual model that shows how soil, climate and vineyard management can affect fruit composition directly or indirectly through canopy microclimate and vine physiology.

Choose long-term and short-term cultivation strategies with the help of precision viticulture technology

Precision viticulture technologies can help with long-term and short-term cultivation strategies to improve grape quality. Among long-term decisions belong terroir selection, vine planting (spacing, row orientation,..) and training, as well as variety and rootstock selection. All of them affect vine growth and grape composition and should be chosen wisely as they can’t be changed easily. While short-term practices refer to seasonal management of canopy, soil, water availability, etc. in a given vineyard zone. 

While precision viticulture technology can help with long-term cultivation strategies decisions by observing the vineyard site and climate over a longer period of time. Long-term decisions are usually more costly for winemakers as they include a selection of different grape variety and its rootstock, moving vineyards to more poleward or higher elevation sites or producing different wine styles in order to adapt to climate changes. While short-term practices can be applied relatively cheaply and based on “current” vintage so that each variability that occurs naturally in the vineyard can be addressed. For example adjust the irrigation regime, adjusting harvest date among vineyard plots, or selectively managing canopy among vineyard. Hereafter we will take a closer look into some short-term cultivation strategies. 

Precision viticulture technologies to produce premium quality grapes

As weather differs sufficiently from year to year also grape quality differs from one vintage to another. To lower the differences among vintages precision viticulture technologies have been developed to help winegrowers adopt vineyard management practice to the vintage. In the last few years, several different precision viticulture technologies have been developed so we will focus on widely available ones, that are used by the winegrowers, and proved to help increase grape quality.

Vineyards can be very heterogeneous looking at pedo-morphological characteristics, cropping practices, and seasonal weather for example. And all these small differences within vineyards cause different vine physiological responses which are not always easy to see with an eye. The technology is here to precisely monitor all the variability and thus characterize the parameters that are regulating vine productivity and quality, and based on measure model key relationships. These models are then used to spatially alter cultural practice. The key is that they acknowledge the spatial variability and provide recommendations to improve the efficiency of vineyard management in order to improve grape quality in a given vintage. To name only a few precision monitoring technologies that can help winemaker produce premium quality grape – geolocation, remote sensing devices, satellites, UAVs, Wireless sensor networks, agbots, spectrophotometer, electromagnetic sensors, etc. 

Precision viticulture technologies - help measure, model and manage vines.

Photo (adjusted from Dokoozlian presentation, 2016): A key for the successful use of precision viticulture technology in the vineyard is to understand that there is a constant circle of information and work needed to produce premium quality wines.

In the second part of the article, we will present precision viticulture technologies that can help winegrowers with specific vineyard management activities.

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Sources:
Orley Ashenfelter; Predicting the Quality and Prices of Bordeaux Wines, Princeton University
Brian Freedman; 
How Technology Is Minimizing The Differences Between Good And Bad Wine Vintages.  In Forbes (online).
Matese A, Di Gennaro SF. 
Technology in precision viticulture: a state of the art review. International Journal of Wine Research. 2015;7:69-81
Ozdemir, Gultekin & Sessiz, Abdullah & Pekitkan, Fatih. (2017). 
Precision viticulture tools to production of high quality grapes. Horticulture. Vol. LXI, 2017
S. L. Sluys; 
Climate influences on the grapevine: A study of viticulture in the Waipara Basin. University of Canterbury, 2006
Figure: Weldon, A. 2003. 
A Wine Climate Model: Using Climatic Variables and GIS for Viticulture Potential. University of Canterbury, Christchurch.
Featured image: Precision viticulture, On Ciencia-e-vinho, from 1.4.2018 (online)