Agriculture Reference
In-Depth Information
Figure 6.2
A deep red
clay loam formed on
basalt in a vineyard in the
Mornington Peninsula
region, Victoria, Australia.
The vine roots (painted
white) go down to 1 m;
the pit depth is 1.2 m. See
color insert.
Soil depth is of less consequence in irrigated vineyards where the normal
practice is to control the water content of the top 50 cm of soil only. This practice
restricts the number of roots below this depth, so the effective soil depth is lim-
ited. Similarly, rooting depth is restricted in shallow soils on impermeable rock,
such as is shown for vines growing on a shallow soil over limestone in figure 3.2,
chapter 3. However, if the rock is fractured naturally, or by deep ripping, vine
roots can grow down cracks and fissures and root more deeply. Examples occur
with vines on fractured schist or shale in the Central Otago region, New Zealand,
parts of Languedoc-Roussillon region, France, and the Collio del Friuli region,
Italy (see figure 1.2, chapter 1). Other examples occur with vines performing well
on shallow soil over limestone that is naturally fissured, as on the mid-slopes of
the Côte de Nuit region in Burgundy, France (figure 6.3); the Terra Rossa of the
Coonawarra region, South Australia (see figure 1.4, chapter 1); the “starfish lime-
stone” of the St. Emilion appellation, Bordeaux region, France; and the calcare-
ous shale and limestone of the Monterey formation in the Paso Robles region,
California. In St. Emilion and Coonawarra, the shallow limestone has in past ages
been enriched with wind-blown silt-size particles, and the rate of release of stored
water from soil and underlying limestone seems to ideally regulate water uptake
for the production of high-quality fruit of intense flavors.
