Soils and plant material in prestigious Bordeaux vineyards impacts on yield and quality

High resolution soil maps (scale : 1/3000) were created for seven of the most prestigious red wine producing estates in Bordeaux, covering in total approximately 400 ha. Soil type and grapevine variety were recorded for each vineyard block of these estates. A quality index was created by considering the destination of the grapes produced on each block, whether they were integrated in the first, the second or the third quality wine produced by the estate. Quality index was averaged over five vintages. Yield was measured for each vineyard block and averaged over five vintages. PEYROSOL (gravely soil) was the most frequent soil type in these estates (44% of the total mapped area). Soils with temporary water logging (REDOXISOL), heavy clay soils (PLANOSOL) and sandy-gravely soils (BRUNISOL) each covered 10% of the mapped area . Highest quality was obtained on PLANOSOLS, ARENOSOLS (sandy soils), BRUNISOLS and PEYROSOLS. Quality was low on COLLUVIOSOLS (deep soils on colluvium), LUVISOLS (leached soils) and REDUCTISOLS (soils with permanent water logging). Cabernet-Sauvignon was the dominant grapevine variety (59% of the mapped area), followed by Merlot (32%), Cabernet franc (8%) and Petit Verdot (1%). On average, the Quality Index was higher for Cabernet-Sauvignon and Merlot compared to Cabernet franc and Petit Verdot. Yield was dependent on soil type and cultivar. Comparison of soil type, cultivar and Quality Index can indicate which relationships between soil type / cultivar contribute to optimum quality performance in Bordeaux.