Cartography of « Terroir Units » is a Tool to Improve the Ré Island Vineyard Management (France)

A study of « terroirs » was achieved from 2003 to 2005 in the whole vineyard of the Ré island (17, France). Over more than 1,990 ha, a cartography at the 1/10.000 scale, including characterization of climatic, pedological, geological and hydrogeological components of « Basic Terroir Units » (B.T.U.) was made. Also, a survey among wine growers was conducted. All data were treated together in a G.I.S. connected to a data base. 22 kinds of map were built (B.T.U. and components, soil water reserve, vine functioning potentials, varieties, rootstocks, viticultural practices and soil management). In a first part of this paper, results concerning climate, soil characteristics, soil water reserve, potentials for an early growth cycle, growth and yield, and also vine behaviour are presented for the main groups of « terroirs ». Other results show the effect of the water table depth on berry composition of several grape varieties. In a second part, examples are given of using advice maps (grape varieties, rootstocks, soil management) to improve the management of the Ré island vineyard, and to assist the vine growers to best adapt their practices to each « terroirs » group. Finally, an example of management of the « terroir-related » grape origin according to types of wine that are elaborated by the cooperative winery of the Ré island, is shown.