Agriculture Reference
In-Depth Information
are also grown. In fact, partly because of its focus on Pinot Noir and climatic sim-
ilarities, this area has sometimes been called the “Burgundy of the West” (Dar-
lington 1999). Since the valley is sandwiched between the Coast Ranges to the
west and the Cascades to the east, the summers are warm, but the winters are cold
and wet (rainfall ranging from 1000 mm on the valley floor and in the south to
1500 mm in the north and on higher areas). A strong French influence is evident
in the choice of vine clones, planting density, trellising, and pruning.
The Soils and Wines
Unlike in Burgundy, soil variation in the Willamette Valley is comparatively sim-
ple. There are two main soil types:
9.6.2
• The
Jory soil
has formed on basaltic colluvium, and typically occurs on the
lower rolling foothills with slopes of 2-60%. It is a very deep (up to 2.5
m) and well-drained soil, of silty clay loam to silty clay texture in the A
horizon, grading into a deep, well-structured B horizon of reddish brown
clay. The profile is acid throughout, ranging from pH 5.6 (in water) at the
surface to pH 5.3 at depth. Shallower soils of the Nekia and Bellpine series
occur on the rounded foothills and abrupt steep breaks, often on colluvium
from basalt, tuff, or sedimentary rocks.
• The
Willakenzie soil
is a moderately deep (up to 90 cm) soil, formed on
colluvium and residual weathered sandstone or siltstone. The texture is silty
clay loam throughout the profile, but there can be an impediment to
vertical water flow at the top of the B horizon and also at the parent
material interface. The pH changes from 6 in the A horizon to 4.7 in the
B horizon.
Generally, the soil water supply is adequate on the Jory, although in some
cases too much water in spring and early summer promotes excess vigor. Many
vineyards on the Jory are without irrigation, and cover crops are used to reduce
vigor and soil erosion. The growers plant in close spacing (1.5
1 m) and pull
fruit to control yields. Water management is more of a problem on the Willaken-
zie, Nekia, and Bellpine soils. Perched water tables may develop in winter in the
Willakenzie, but there is often a lack of soil water in dry summers, because of
poor root penetration into the subsoil. Irrigation is used to advantage here. A
number of growers are conscious of environmental concerns about wine produc-
tion and lean toward minimum inputs (i.e., low nutrients and minimal use of pes-
ticides), while not wanting to be wholly “organic.” Thus, they sow a legume in
the cover crop, make and apply compost, and spray soft rock phosphates onto the
vines. Lime is applied to raise the soil pH to 5.5, as necessary.
The relatively uncomplicated soil distribution and the high level of nutrient
management practiced by the growers may be reasons why the soil is not often
identified as a major factor in the
terroir
of the Willamette Valley. Nevertheless,
as with the granites and vulcanized schists of Haut-Beaujolais and the Cambrian
volcanics of Heathcote, Victoria (section 9.7.3), some believe that particular min-
erals derived from the basalt confer a distinctive character to the grapes grown on
Jory soil (Darlington 1999).
