Satellite imagery used in management and harvesting of wine grapes. Pilot projects at four vineyards in Northern Greece have confirmed that satellite imagery may be used by agronomists and winemakers in optimising the management and harvesting of wine grapes. Vana Giavi and Penelope Richardson report
In the past decade, agriculture in Europe and worldwide has undergone a substantial change, bringing increased food security and production. But this has led to significant harmful environmental consequences in terms of water pollution, greenhouse gas emissions and damage to our natural surroundings. At the same time, very high-resolution multispectral satellite data such as from WorldView-2 gradually became more available, providing data in the red/near-infrared transition zone of the vegetation reflectance spectrum, which marks the boundary between absorption by chlorophyll and scattering by leaves’ internal structures. This combination was the motivation that brought remote sensing researchers from the National Technical University of Athens in Greece together with grape growers and winemakers.
Every year since 2012, concurrent satellite, airborne and field campaigns have been scheduled during the ‘veraison’ period, the 10-15 day time-window during which grapes change their colour and begin ripening. During the growing season, the maturity and quality of grapes vary across a region and even within a single vineyard. Winemakers carefully monitor the grapes throughout the season to determine when nutrients, pesticides and additional water should be applied to optimise growth. As the harvest nears, the winemakers examine grapes for signs of maturation and sugar content to select the precise time for picking. Vines are even categorised by grape quality and assigned to specific barrels/tanks in anticipation of the wine they will yield.
Winemakers and viticulturists rely on several tools to monitor crop health and grape ripening, including handheld reflectance spectrometers. In this project, a 512-band spectrometer operating in the 350-1050nm range was used to collect spectral signatures of 20 grape varieties.