Agriculture Reference
In-Depth Information
com.au
), whose members apply the National Standard for Organic and Biodynamic
Produce developed by Standards Australia under the auspices of the Department of
Agriculture (www.daff.gov.au/agriculture-food/food/organic-biodynamic).
To be certified as organic, a vineyard must be established on organic princi-
ples from the beginning or must undergo a three-year conversion period, although
after two years the wine can be labeled as “in conversion.” Certified organic pro-
duction means that grapes are grown without insecticides, herbicides, fungicides,
and chemical fertilizers, other than those approved by the certifying agency, using
cultural practices that minimize adverse effects on the soil and wider environ-
ment. Genetically modified plant material cannot be grown, nor can genetically
modified yeast be used in fermentation. Chapter 6 includes an appraisal of the
overall advantages and disadvantages of organic viticulture and a summary of any
observedefectsonwinequality.
Complementing the organic movement, winegrowers in the major
wine-producing countries are encouraged to adopt an integrated production sys-
tem, discussed in chapter 6. Briefly, such a system involves minimizing pesticide
and fungicide sprays through integrated pest management to encourage a balance
between natural predators and pests and practicing good canopy management to
avoid disease problems. Fertilizer recommendations are still based on soil testing,
andorganicmanures,compost,andmulchareusedwhereverpossible.Mid-row
cover crops or permanent grass swards are advocated to improve soil structure and
provide a favorable habitat for beneficial organisms and predators of pest insects.
Cultural Practices for Organic Viticulture
In organic viticulture, weeds are controlled by mechanical cultivation instead of
herbicides.Mowingsfromamid-rowcovercropcanbethrownunderthevines
to serve as mulch. A cover crop containing legumes can be cultivated into the soil
as “green manure.” The slow release of mineral N as the green manure decom-
poses minimizes the chance of any NO
3
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formed being leached before the vine can
absorb it.
Farm animal manures must be composted or followed by at least two green
manure crops after application. Biosolids derived from composting sewage sludge
are generally prohibited unless specifically exempted by the certifying agency.
The most commonly used manures in vineyards are poultry manure, followed
by sheep manure. Composted manures should be pelleted to produce an odor-
less product in which N is at first stabilized by microbial immobilization but the
C-to-N ratio is reduced to less than 25 so that net N mineralization occurs in
the soil (see figure 3.5). Composted manures and biosolids (if permitted) provide
macronutrients such as N, P, K, and S; micronutrients, trace elements, and salts;
