Satellite imagery : a tool for large scale vineyard management

Remote sensing, using Near Infra Red wavelength, can characterize within-vineyard variability using vegetation index. Between 2007 and 2009, a study was led on the vineyards of a cooperative winery, in Fitou area (France) aiming at characterizing vineyard oenological potential. A vegetation index, green leaf cover, developed on crops (wheat, rice, corn…) was implemented on vineyards.
In a first stage, it was proved that the use of 2m/pixel resolution gave the same precision of field variability mapping than a 0,50 m/pixel resolution, which made possible the use of satellite datas, covering a 57 600 or 302 500 ha zone (respectively 24 km x 24 km or 55 km x 55km). Then a heterogeneity index, adapted from Pringle’s opportunity could be calculated for each vine, which can be characterized by an average leaf cover index (a “vigor” index), and an heterogeneity index. Detection of high levels of bare soil in a vine can also be identified automatically.
Based on these indexes, each vine can be characterized and gathered with other vines with the same characteristics (homogeneous vines with either low or high vigour, heterogeneous vines, abnormal vines with excessive bare soil….). According to such a classification realized just before veraison, the winery could select bins corresponding to each quality of vines. Separate vinifications proved sensorial differences on wines: homogeneous vines would give wines with intense jammy and spicy flavours, interesting body in mouth, and smooth tannins, whereas heterogeneous vines tended to produce wines with more red fruit and grassy aromas, and coarser tannins. These differences are consistent from year to year. This selection method is used on 50 % of carignan vines by the winery, which cannot be visited by its technical staff.