Agriculture Reference
In-Depth Information
may suffer nutritional stress, and hence reduced growth, through the effect of active
aluminum (Al) and possibly manganese (Mn). On calcareous soils (pH(CaCl 2 ) 8
and above), lime-induced chlorosis (see “Micronutrient Fertilizers,” chapter 3) is not
easily avoided unless V. vinifera varieties on own roots or lime-tolerant rootstocks are
used. Although rootstocks derived from V. rupestris and V. riparia are lime-sensitive,
V. berlandieri , being a native of the limestone hills in southwest Texas and New
Mexico, is the most lime-tolerant of the American species and confers this tolerance
on its crosses. Of these crosses (see table 5.8), the ranking from most lime-tolerant to
least is 140 Ruggeri >5BB Kober >420 Millardet >110 Richter >1103 Paulsen >99
Richter >SO4 > 5CTeleki. Rootstocks with a vinifera parentage such as 41B and
Fercal are the most lime-tolerant but should not be used where phylloxera is a threat
because they are very sensitive to attack by phylloxera.
Vine Balance and Wine Quality
The overall aims in selecting a rootstock-scion combination are as follows:
1. Avoid or minimize the influence of adverse soil factors (e.g., phylloxera,
nematodes, salt, and pH)
2. Achieve a balance between root and shoot growth consistent with the
yield and grape quality objectives for the vineyard
Depending on site potential, various rootstock-scion combinations range
widely in performance from high to low vigor. Generally, the most vigorous
vines are those with the most extensive root systems and greatest drought tol-
erance. Thus in table 5.10 the more vigorous rootstocks are recommended
for dry-grown vineyards on shallow- to medium-depth soils of lighter tex-
ture, whereas less vigorous rootstocks are recommended for deeper soils and
more favorable growing conditions. In Australian trials, the recently released
Commonwealth Scientific and Industrial Research Organization rootstocks (see
table 5.8) confer low to moderate vigor on Shiraz, giving higher yield-to-pruning
weight ratios than popular rootstocks such as 1103 Paulsen and Ramsey.
Another factor affecting vine vigor and vine balance is the uptake of major
nutrients such as N and K. Some organic-rich soils have high N availability through
the natural process of mineralization, but this can be managed through the use of
a grass cover crop and irrigation control (e.g., keeping the top 15-20 cm of soil
dry to restrict N mineralization and the uptake of N by the vines). Rootstocks vary
in their uptake of K, and this can be an important selection criterion, especially
for deep sandy soils in the Murray-Darling region, Australia, that are naturally
high in available K. For example, rootstocks derived from V. champanii (Ramsey,
Freedom, and Dog Ridge) accumulate more K than 110 Richter, 1103 Paulsen,
5C Teleki, 5BB Kober, and SO4.
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