Sustainable viticulture
involves all aspects of farming: viticulture, soil management, water
management, pest management, habitat management, human resources (growers,
their family members, and their employees), and wine quality. Therefore a large
number of farming practices are involved and it is not possible to discuss them
all here. The Lodi Winegrower's Workbook not only discusses of the sustainable
farming practices, it contains a measurement system that allows a grower to see
their level of implementation of sustainable farming practices in each of their
vineyards. Some of the important sustainable viticultural practices promoted by
LWWC's program are briefly discussed below.
Monitoring and Using
Economic Thresholds: There is an old time expression that the best thing a
farmer can put on their field is their shadow. This means being out in the
field and observing what is happening. The foundation of any IPM/sustainable
farming program is monitoring the numbers of pests and their natural enemies
frequently and keeping a written record of what is observed. Control of a pest
is not taken until the level of the pest has reached a point where the damage
it will cause exceeds the cost of controlling the pest. This is the economic
threshold.
Planting Cover Crops:
Growers are encouraged to plant cover crops because they improve soil quality
by adding organic matter, building soil structure, increasing the populations
of soil microorganisms, and improving water penetration. Permanent cover crops
reduce dust in vineyards, because disking is no longer necessary. Dust
exacerbates spider mite problems in vineyards. Cover crops may also provide
refuge for some natural enemies of vineyard pests.
Leaf-pulling or Leaf
Removal: This techniques involves removing leaves around the grape cluster
when the berries are about the size of a pea. This improves air circulation in
the grape canopy, reducking the likelihood of bunch rot. Research has shown
that leaf-pulling is as effective in preventing bunch rot as a fungicide spray.
Leaf-pulling also allows for better coverage of mildew sprays. It also exposes
grape bunches to sunlight and this significantly improves winegrape quality. An
additional benefit of leaf-pulling is that leafhoppers and mites are
concentrated on these leaves at the time of year that leaf-pulling is done
(when berries are pea-sized) and this reduces leafhopper and mite
numbers.
Use of Organic
Fertilizers: Adding compost or manures to vineyard soil enhances soil
quality through adding organic matter, improves soil structure, and increases
populations of soil microorganisms. These organic fertilizers can reduce or
eliminate the need for synthetic nitrogen fertilizers.
Owl Boxes and Raptor
Perches: Placing owl boxes at the edge of vineyards increases the owl
populations. Raptor (hawks, etc) perches provide places for hawks to sit an
look for prey in and around vineyards. Owls feed on gophers and hawks feed on
voles, which are pests in some vineyards.
Reduction in Pre-emergent
Herbicide Use: LWWC growers are encouraged to lower the rates of
pre-emergent herbicides or eliminate their use altogether. Some pre-emergent
herbicides have been implicated in ground water contamination.
Release of Mite
Predators: Predacious mites are important natural enemies of spider mites
in vineyards. They are present in most vineyards but in some cases releasing
several thousand predacious mites per acre in a vineyard can re-establish their
numbers sufficiently to bring about long-term control of a spider mite
problem.
Use of Dr. Doug Gubler's
Powdery Mildew Model: The UC Statewide IPM program maintains a internet
website where growers and PCAs can visit and access a computer model developed
by Dr. Doug Gubler. This model helps the user determine the optimum time to
spray for powdery mildew. Growers are encouraged to use this model to optimize
their powdery mildew spray program.
Use of Drip
Irrigation: Drip irrigation systems minimize water use in vineyards.
Growers can apply fertilizers to the vineyard through the drip system. Since
the fertilizer is applied to the soil where the grape roots are concentrated
less fertilizer is needed when compared to broadcast fertilizer applications.
Applying fertilizers through the drip system can result in up to a 50%
reduction in fertilizer use. Drip systems deliver water to the vineyard much
more uniformly than furrow irrigation and some growers feel that drip irrigated
vineyards are less prone to spider mite problems.
Use of 'Soft' Pesticides
and Reduced Pesticide Rates: If a pesticide application is necessary
growers are encouraged to use the most environmental sound material available.
Furthermore, the minimum rate of pesticide per acre necessary to achieve
control is encouraged. This includes using 'every-other-row'
spraying. |
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