Agriculture Reference
In-Depth Information
Figure 9.13
Very old Shiraz vines on a sandy ridge at Chateau Tahbilk, Nagamie Lakes Sub-region,
central Victoria. Photograph by the author. See color insert.
• The vegetation, strongly determined by climate, but which also influences
soil formation through root action and the return of litter
• The length of time the limestone has been weathering, which influences
the depth of accumulation of resistant mineral residues and humified
organic matter
The important effects of climate (macro-, meso-, and microclimate) on vine
growth and fruit ripening have been convincingly argued by Gladstones (1992).
The rates of growth and ripening strongly influence fruit quality and wine char-
acter through the ratio of sugars to acidity, juice pH, the accumulation of non-
volatile flavonoids (condensed phenolic compounds), and the more volatile com-
pounds responsible for subtle fruit flavors and aromas. Others such as Smart and
Robinson (1991) assert that control of the microclimate by canopy management
is especially important in regulating the vine's physiological processes to achieve
good fruit quality and wine character.
However, we can also see from the evidence of Burgundy, Bordeaux, the Napa
Valley, and Coonawarra, that the soil is an important component of a vineyard's
terroir
. To identify the key relationship between the soil and wine character in
particular, few would go to the extreme of “tasting the soil”—said to have been
done by the Cistercian monks of the Clos de Vougeot in the Côte d'Or (John-
son 1994). The complex relationships between a soil's physiochemical and bio-
logical processes and the chemistry of the berries, fermentation of the must, and
maturation of the wine is unlikely to be elucidated in the immediate future. But
certain general conclusions about the influence of soil on wine character and qual-
ity can be drawn, as follows:
