Approaches to Grape Growing Flashcards
Explain conventional viticulture?
In the second half of the twentieth century, viticulture, in common with production-oriented farming for other crops, underwent a significant change. In effect it became intensive fruit farming. Aside from small-scale artisan grape growing, the new approach was widely implemented around the world. The aims included raising production levels and reducing labour requirements. This was achieved by mechanisation, chemical inputs, irrigation and clonal selection. Viticulture became a monoculture. Vineyards were kept weed free by ploughing between the rows and spraying with herbicides. The use of agrochemicals in the vineyard to control pests and diseases significantly increased. There was also an increased use of mineral fertilisers.
By the late twentieth century there was an increasing realisation that spraying pesticides on a regular basis and routine use of mineral fertilisers were harmful to soil quality, expensive, detrimental to the environment and potentially hazardous for vineyard workers and even the consumer. Intensive fruit farming methods had become an increasing worry to many grape growers, consumers and legislators. In many major vineyard regions there are increasing efforts to reduce the quantity of chemicals used.
Explain the advantages and disadvantages of monocultures?
Monocultures have advantages and disadvantages. The advantages include:
ability to mechanise the work in the vineyard reduction of competition from other plants
ability to tend to the specific needs of the grape variety planted (irrigation, nutrition level, treatments against hazards, pests and diseases) and to increase yields while reducing costs.
The disadvantages are that:
any plants in a monoculture are much more prone to diseases (e.g. the common fungal diseases) and pests and therefore need more treatments or protection nutrients can be depleted as there is no natural ecosystem to replenish nutrients, requiring more applications of fertilisers
residual chemicals can find their way into ground water or the air, creating environmental damage.
Explain Sustainable Viticulture?
Sustainable grape growing has three themes: economic, social and environmental sustainability.
The focus in this unit is primarily with environmental impact. In this sense, sustainable viticulture aims to promote the natural ecosystems in the vineyards, maintain biodiversity, manage waste, minimise applications of chemicals and energy use, and reduce the impact of viticulture on the wider environment.
Grape growers are encouraged to develop an in-depth understanding of the lifecycles of the vine and of vineyard pests and to monitor weather forecasts so that they can predict and prevent a pest or disease outbreak before it occurs. Rather than simply following a regimented calendar of spraying, this enables them to time the applications so that they have the greatest impact. As a result, fewer applications are needed.
Integrated pest management (IPM, also known as lutte raisonée) is a key part of sustainable agriculture. It builds on some of the insights of organic viticulture, but it is prepared to use chemical interventions when necessary. It includes setting thresholds at which action needs to be taken (e.g. if pest populations reach a certain level), identifying and monitoring pests, setting up preventative measures, and evaluating and implementing control options (if threshold levels are exceeded and preventative measures have not been effective).
The grape grower regularly monitors the scale of potential problems and only intervenes before they reach an economic threshold (i.e. when the level of damage will exceed the cost of intervention). They seek to anticipate problems, to boost the vine’s own defence mechanisms and to act at the most effective time. Acting in this way helps to limit serious damage to crops, reduce the amount of chemicals used, save on costs and prevent plants building up resistance to those chemicals.
What are the advantages and disadvantages of sustainable viticulture?
The advantages of sustainable viticulture are:
A more thoughtful approach to grape growing, with attention to the economic, social and environmental impact of viticulture.
The deployment of a scientific understanding of the threats to successful grape growing (pests and diseases) to minimise the number of interventions needed.
A reduction in the spraying of synthetic and traditional treatments.
The consequent cost saving that has incentivised grape growers to work in a more sustainable way.
The disadvantages are:
The term is not protected and therefore can be used to promote wine without a clear set of standards.
The danger that nationwide standards for sustainability can be set too low. New Zealand’s high rate of uptake for its scheme – virtually all commercial grape growers – has both been praised for reducing the amount of pesticides used but criticised for setting too low a bar for sustainable certification.
Explain organic viticulture?
Organic viticulture seeks to improve the soil of the vineyard and the range of microbes and animals, such as earthworms, within it and thereby increase the health and disease-resistance of the vine. It rejects the use of man-made (also known as synthetic) fertilisers, fungicides, herbicides and pesticides. The key features are:
The application of compost, which breaks down in the soil providing a slow release of nutrients for vines, and improves the structure and increases the biomass in the soil (the total quantity or weight of organisms in a given area or volume).
Cover crops are also often used to prevent erosion of the soil and to contribute to the improvement of the life of the soil. This can be through ploughing them in (‘green manure’) or by improving biodiversity.
Natural fertilisers may also be used (animal dung, natural calcium carbonate, etc.). The idea is to restore the natural balance of the vineyard.
The monoculture of vineyards can be reduced by growing cover crops, planting hedges and establishing ‘islands’ of biodiversity.
Organic grape growers use traditional remedies such as sulfur and copper sulfate to combat mildews, and monitor the weather closely to determine
when spraying against mildew is really necessary.
However, build-up of the heavy metal, copper, in the soil where frequent sprays are necessary has led some to conclude that careful use of longer-lasting synthetic chemical sprays are a better option for the environment. Reduced need to use tractors in the vineyard is also a bonus for those using synthetic chemicals.
In addition, organic grape growers can make use of natural predators and ecosystem mechanisms. For example, to defend against grey rot, the bacterium Bacillus subtilis can be introduced, which competes with Botrytis cinerea for space on the grape. ‘Sexual confusion’ techniques are also commonly used. They involve the use of pheromone tags or capsules to disrupt the mating patterns of insects such as moths and mealy bugs, and in this way, limit their populations.
There are many certification bodies throughout the world. Although many of these organisations operate on similar principles, the exact standards each one sets may be slightly different. Therefore, and perhaps confusingly, some wines made from organically-farmed grapes may have been subject to stricter rules than others. All certification bodies should meet the standards set by IFOAM (International Federation of Organic Agriculture Movements). A universal requirement, however, is that the vineyard must undergo a period of conversion working to organic standards before it can be certified. Certification adds an extra cost to the production of wine. However, it may be that the grape grower can gain an advantage in promoting and selling such wine depending on the target consumer and market.
What are the advantages and disadvantages of organic viticulture?
The advantages of organic grape growing are:
- making the health and disease-resistance of the vine and the health of the soil central aims of the grape grower
- the reduction in the number of chemical treatments in the vineyard and the elimination of spraying synthetic chemicals
- a saving on the cost of synthetic chemicals.
Disadvantages of organic viticulture are:
- a possible small reduction in yield generally
- possibility of significant reductions in yield in difficult years (e.g. long periods of rainfall or high humidity)
- increased reliance on copper sprays, which may in turn lead to the build-up of heavy metal in the soils
- the cost and time expended on certification where this is sought.
Explain biodynamic viticulture?
Biodynamic viticulture is based on the work of Rudolf Steiner and Maria Thun. It includes organic practices, but also incorporates philosophy and cosmology. The vineyard soil is seen as part of a connected system with the planet Earth, the air and other planets. Practitioners adapt their grape growing practices to coincide with the cycles of the planets, moon and stars.
Homeopathic remedies called ‘preparations’ are used to fertilise the soil, treat diseases and ward off pests. These
procedures include:
Preparation 500 (horn manure) – This is made by stuffing cow manure into a cow’s horn and burying the horn in the soil throughout the winter. It is then dug up and the contents are dynamised. This is the action of stirring the contents of the horn into water (creating a vortex and then reversing it) so that the water memorises the power of the preparation, which can then be passed on to the vineyard. This preparation is then sprayed onto the soil as a homeopathic compost.
Preparation 501 (horn silica) – This is made by filling a cow’s horn with ground quartz (silica) and burying it for six months. It is also then dug up, dynamised and sprayed onto the soil. The manure is believed to catalyse humus formation and the silica is thought to encourage plant growth.
Compost – Biodynamic grape growers believe that biodynamic compost has to be first ‘activated’ by a series of starters added in tiny quantities (yarrow, chamomile, nettle, oak bark, dandelion or valerian prepared in various ways; for example, the yarrow in a deer’s bladder). These are known as preparations 502–507 and they assist with the decomposition of the compost.
Like organic grape growers, biodynamic grape growers use traditional chemicals to spray against disease, including sulfur and copper sprays. Some practise ashing: spreading the ashes of burnt weed seeds or harmful animals (e.g. rats or sparrows) on the vineyards to ward off these hazards.
The most common certification body for biodynamic grape growers is Demeter, which sets international standards for farming and animal husbandry. It has member organisations in many countries. The standards for biodynamic viticulture include organic certification of vineyards as a baseline, but then goes on to specify the principles that should be followed. Each national association interprets these in the light of local circumstances.
The additional costs of biodynamic grape growing are estimated to be little more than organic growing, generally due to the need for additional labour to tend the vineyard.
The advantages and disadvantages of biodynamic grape growing include those of organic grape growing.
Explain precision viticulture
Traditionally, grape growers have adopted a uniform approach to work in the vineyard, whether this is in preparing the soil, pruning the vines or applying treatments. However, both experience and recent research shows big variations in the response of vines, even in the same vineyard or plot.
In response to this, precision viticulture (PV), a branch of precision agriculture, makes use of data collected from the vineyard (soil, vigour, topography, plant growth) to respond to changes from plot to plot and from row to
row. The data is collected by sensors either on aircraft (‘remote’) or mounted on a tractor or harvester in the field (‘proximal’). Geospatial technology such as global positioning systems (GPS) and geographical information systems (GIS) allows the data to be presented visually in the form of maps. The data collected can be about the composition of soils, the rate of growth of the canopy and many other examples.
Interventions in the vineyard are then targeted in the light of the data collected. This is known as variable-rate application technology. Thus, the grape grower can respond to the significant differences from plot to plot (or smaller) in the vineyard. The idea is for all key interventions, for example, pruning, leaf removal, treatments, irrigation, crop thinning and harvesting, to be carried out precisely with the aim of producing the best quality and yield, reducing environmental impact and, where possible, reducing costs on treatments. Examples of changes made in the light of the data include changing the rootstock half way along rows of vines as the soil gets richer or increasing levels of leaf-stripping in a high vigour area.
As precision viticulture requires considerable upfront investment (sensors, software), it is only an option in large scale viticulture or on high-value, smaller estates. It has been most widely used in California and in Australia, and is most effective where the data collected is used systematically to control treatment application rates or irrigation rates. Precision viticulture not only seeks to respond to variations (e.g. in vine vigour) in the vineyard, but, if possible, to reduce them. Also, it can be used to identify different quality zones within the same vineyard.
What are the advantages and disadvantages of precision viticulture?
Advantages include:
detailed understanding of variations in the vineyard that affect yield and quality between and within vineyards
ability to tailor a wide range of interventions (choice of variety and rootstock, canopy management, treatments, harvest dates) to individual blocks or even rows of vines, with the aim of improving yields and/or quality.
Disadvantages are:
initial cost of remote data collection
cost of sensors and software and of either consultancy or trained staff to interpret the data and make interventions in the light of it.
