Effects of water and nitrogen uptake, and soil temperature, on vine development, berry ripening and wine quality of Cabernet-Sauvignon, Cabernet franc and Merlot (Saint-Emilion, 1997)

Wine quality depends largely on berry ripening conditions in relation to soil and climat. The influence of the soil has been studied in Bordeaux since the early Seventies (SEGUIN, 1970; DUTEAU et al., 1981; VAN LEEUWEN, 1991; VAN LEEUWEN et SEGUIN, 1994) and, more recently, in the Val de Loire (MORLAT, 1989), the Alsace (LEBON, 1993) and the Costières de Nîmes regions (MARTIN, 1995). Its influence is complexe, because both physical (soil temperature, water uptake) and chemical (nitrogen uptake) soil parameters interfere on vine development and berry ripening.
Vine development, berry ripening and wine quality were studied in Saint-Emilion (Bordeaux area, France), in 1997, in relation to three different soil types:
– G: Gravelly soil
– S: Sandy soil, with a water table in reach of the roots
– C: Heavy clay soil
Three cultivars were compared, Vitis vinifera Cabernet-Sauvignon, Cabernet franc and Merlot. Water uptake, nitrogen uptake and soil temperature were measured to explain the different vine expressions on the nine plots (3 soils x 3 cultivars).