Agriculture Reference
In-Depth Information
of French viticultural areas: the Appellation d'Origine Contrôllée (AOC) system,
which is based on many years' experience of the character and quality of individ-
ual wines from specific areas. There are many examples in France of distinctive
wines being produced consistently in particular localities, of which some of the
better known are the Grand Cru and Premier Cru of the Côte d'Or in Burgundy,
the First and Second Growths of the Médoc in the Bordeaux region, and the vin-
tage champagnes of Champagne.
In spite of the restrictive aspects of the appellation concept (section 9.2.1),
this approach has been adopted with various modifications in other European
countries. Increasingly, this concept underpins the recognition of American Viti-
cultural Areas (AVA) in the premium wine areas of the Napa and Sonoma Val-
leys in California. Until recently it had not featured strongly in the viticulture of
other countries, such as Australia, where from the earliest times Busby (1825, p.
7) wrote that “with the exception, perhaps, of a very stiff clay, or a rich alluvial
loam, there are good vineyards on almost every description of soils.” However,
where there is a perceived marketing advantage in associating a wine with soil in
a specific region, the
terroir
concept is being exploited. One example is the Terra
Rossa soil of the Coonawarra region in South Australia, and another the Red Cam-
brian soil of the Heathcote region in Victoria.
The Importance of Soil Management in Vineyards
The role of
terroir
in determining wine character has been comprehensively ex-
plored for French vineyards by Pomerol (1989) and Wilson (1998) (for a discus-
sion of terms relating to wine, see box 1.1). Their approach has been to infer the
influence of soil on wine through the surrogates of geology and landscape, rather
than through properties of the soil itself. This impression is reinforced by the de-
scriptive and cartographic approach to defining different
terroir
in many of the
articles of the international colloquium on “Les Terroirs Viticoles” in 1996. For
the present, the subtleties of soil factors in determining the distinctive character
of wines remain primarily the concern of wine makers supplying the premium
end of the market. But good soil management in growing grapes for wine, or
“wine growing,” is important to all producers for the following reasons:
• The grape vine (
Vitis vinifera
) is a long-lived perennial. Whether grafted on
a rootstock or grown on its own roots, each plant is expected to grow for
many years. Over the 40- to 50-year life of a commercial planting, with as
many as 10,000 plants per ha (as in the Médoc of France), the vines will
root deeply and explore virtually all the soil available. This means that the
relationship between soil and vine must be as harmonious as possible.
• Most importantly, the soil supplies water and nutrients that influence the
vigor of the vine, the balance between vegetative growth and fruit, the yield
of grape berries, and berry quality.
• A number of pests and diseases of grapevines, such as nematodes,
phylloxera, and the spores of the downy mildew fungus, live in the soil and
can have a profound effect on the health and longevity of the plants.
• Maintaining the soil in good condition physically (soil structure),
chemically (adequate nutrients and no toxicities), and biologically (organic
matter turnover and biodiversity) is important for sustained yield and vine
longevity.
1.1.1
