Agriculture Reference
In-Depth Information
identify zones within a vineyard that can be managed separately, from planting
through to producing fruit and ultimately harvesting. When key soil and climate
variables are combined into a model, similar to the local site index described in
chapter 2, which is linked to a geographic information system, the resulting map
can be interpreted as defining digital
terroirs
for the site. Figure 6.8 shows the
map output of such a model that has been developed for the Cowra region, New
South Wales, Australia. Proffitt et al. (2006) give more examples of digital maps
of variability in soil properties and vine vigor in their topic
Precision Viticulture
.
Chapters 3 through 5 describe how the expression of soil variability through
nutrient supply, soil structure, aeration, drainage, soil strength, water supply,
salinity, sodicity, and soil biology can be recognized. Actions to remedy any onsite
constraints and offsite effects of winegrowing are recommended.
Possible applications of PV include differential soil amelioration, through the
use of lime or gypsum (see box 3.6, chapter 3), installing under drainage in parts
prone to waterlogging (see “How to Improve Soil Drainage,” chapter 4), and plan-
ning the design and layout of an irrigation system to supplement soil water (see the
next section). For example, through the choice of dripper placement and delivery
A local site index for a vineyard in
central west New South Wales, Australia.
Local Site Index
< 0.30
0.30 - 0.35
0.35 - 0.40
0.40 - 0.45
0.45 - 0.50
0.50 - 0.55
0.55 - 0.60
0.60 - 0.65
> 0.65
N
W
E
0
125
250
500
Metres
S
Figure 6.8
Map showing the digital
terroirs
for a vineyard in the Cowra region, New South
Wales, Australia. The
terroirs
are defined by a local site index incorporating site-specific net
radiation, temperature differences due to aspect and height, readily available water, clay-to-
silt ratio, and root zone depth. Sites with low local site index are better suited to late varieties
because of lower temperatures and frost risk. These sites also have high readily available water
and are not suited to vigorous varieties like Shiraz. (Courtesy of Dr. James Taylor, Australian
Centre for Precision Agriculture, Sydney, Australia.) See color insert.
