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A Technical Guide for Wine Producers
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Requirements For Organic Cultivation Of Wine Grapes*
Pieter Raath & Johan Fourie
The growing interest in organic cultivation of wine grapes in South Africa elicits regular enquiries about what exactly organic farming entails. The basic cultivation requirements are briefly discussed below.
Certification
Consumers of wine produced from organic grapes accept that producers of this wine endorse the principles of organic cultivation and adhere strictly to certain minimum production requirements. Supermarkets and marketers therefore protect their clients by insisting that certification bodies acknowledged and trusted by themselves clearly stipulate the requirements for organic cultivation and audit the farms in order to ensure that producers comply with the minimum production standards. A producer who claims to cultivate grapes organically, must therefore be able to prove that he complies with these conditions. Without approval to use the logo of a specific certification body, producers are not entitled to sell their wine as organic. In Fig. 1 examples are given of logos of various certification bodies that are acknowledged in Europe.
Each certification body has its own set of production standards based on the minimum standards of the European Union (EU). This indicates clearly which cultivation practices are unacceptable, which products may be used and which are prohibited. It also provides guidelines for what has to be achieved in terms of soil fertility, energy conservation and protection of vineyards against contamination by prohibited products. In this article the SGS organic standards (SGS, 2000) are used as a guideline to stipulate specific cultivation requirements.
Organic fertilisation of wine grapes
The use of fertilisers is prohibited. A producer who would like to have his grapes certified as organic, should therefore prove that he:
Where deficiencies of specific elements, apart from N, occur in the soil or vine, the following fertilisers may be used with the prior approval of the certification body:
Rock phosphate, Gypsum,
Magnesium sulphate,
Wood-ashes,
Potassium sulphate,
Lime (pH adjustment),
Calcium chloride,
Trace elements,
Blood- and Bonemeal
These fertilisers are considered supplementary to organic fertilisation and do not replace the recycling of organic matter as fertiliser. Trace elements may be applied in various forms, but only after soil or plant analysis has indicated specific deficiencies. The principle should be to limit external input to a minimum.
Organic weed control
No chemical herbicides are allowed. The options that exist in an organic production system, are therefore:
Hoeing: Thermal control (flame or hot water)
Some of these practices were investigated in an Integrated Production System in order to compare the cost, profit and return of each practice (Table 1).
Where weed control occurred with a permanent cover crop or mechanical cultivation in the row, the input cost was higher and the production and cumulative profit lower than in the vineyard where natural weeds were chemically controlled over the entire surface. Although the input cost was the highest where a straw cover crop was placed over the entire surface, the cumulative profit was more than that of the vineyard in which the natural weeds were chemically controlled over the entire surface. The input cost of the annual cover crop system was more acceptable, however, and from an economic point of view, the vineyard performed the best. For now it is recommended therefore that an approach be followed in which straw is placed in the row and an annual winter cover crop with a short growing season (rye, triticale) sowed in the row. Towards the end of September, the cover crop can be flattened lightly with a disc. As much as possible of the fibre should be left on the surface (Fig. 2) so that maximum biological weed control might be obtained in the course of the growing season. However, the medium to long term economic sustainability and effectiveness of all the different weed control systems in an organic production system remain to be proven under local conditions. Research initiated in March 2000 will shed more light on this subject.
Organic pest and disease control
The use of synthetic disease control products or insecticides, as in the case of chemical herbicides, is prohibited. On the other hand, products produced on the farm from plant, animal and micro-organisms may be used. Commercial natural/biological pest control products may also be used, provided they are registered for wine grapes.
In general copper and sulphur, as well as plant and compost extracts, are used to control fungal diseases. For insect control soaps, plant oils (neem oil in particular), bacteria and extracts of strongly scented plants are used.
Injudicious use of pest and disease control products is not allowed and any use thereof should be justifiable. In an organic system, the goal should be to create environmental conditions in which pests and diseases do not multiply in an unlimited fashion, rather than using products that could destroy the beneficial insects. A restriction is therefore placed on the use of certain organic pest control products, and proof must be given that significant crop losses will occur unless such a product is applied. The use of weather stations and other aids to predict a possible outbreak of diseases and pests is therefore recommended in order to limit spraying of any chemical products to the minimum.
Wine from organic grapes
Since it is hardly possible to make exclusive use of purely natural processes and methods in the vinification process, wine is not made organically and can therefore not be marketed as "organic". The term "organic wine" is a misnomer since only the grapes from which it is made, are organically produced. Wine should thus be marketed as "produced from organic grapes". To be able to market wine in this way and in order to be allowed to use the logo of a specific certification body, the winemaking process and the final product have to comply with certain conditions, however. Firstly, there is a limitation on the amount of sulphur that the wine may contain. These values are listed below (Table 2).
Cellar practices, such as general hygiene, cleaning of fermentation tanks and the steps taken to ensure that organic grapes and the resultant wine do not mix with conventional grapes or wine, also form part of the certification process.
Conclusion
It should be clear from the above that a producer has to prove to the certification body through his production management system that he supports and practices the basic philosophy behind organic farming. Certification bodies are mainly concerned with determining, by means of their audits, whether the producer understands and applies this philosophy in practice (Fig. 3).
Producers who are interested in converting to organic production, are advised to do the following:
SGS, 2000. SGS Organic Production Standards, SGS South Africa (Pty) Ltd., Stellenbosch. 70pp.
RAATH, P.J., 2000. Beginsels en vereistes van organiese verbouing van wyndruiwe in die Kusstreek. In: Grondkundige Aspekte vir Optimum Wynkwaliteit in die Kusstreek, ARC Infruitec-Nietvoorbij.
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