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| Grape growing, winemaking and wine maturation |
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| Techniques of viticulture |
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It is usually during dormancy that the vine is pruned (although some growers wait until the sap begins to rise). This is when the yield of the following year is determined. Pruning, or cutting back the canes from the previous years’ growth, is one of the most important vineyard jobs carried out during in the vineyard. Pruning determines the number of buds on the vine, and thus influences the potential yield of the vineyard site. It is also done to ensure a regular yield from the vine, since the vine gives fewer bunches, but each bunch weighs more than it would if left unpruned.
There are essentially two types of pruning – spur pruning and cane pruning. In spur pruning, each cane is cut short, to two buds, while in cane pruning they are left much longer – six to twelve buds each.
Vines are also trained to grow in a particular fashion in order to make the work in the vineyard easier. The simplest way is bush training. In this type of training the vines are staked, and grow independently. The vine is spur pruned, with the canes all coming off the center of the vine or head. As the shoots grow, they are sometimes tied together to give the vine shape (gobelet). This system is used in warm countries because it provides needed shade to the grapes and because there is less risk of rot and mildew. It is less expensive to install because no wires or supports are needed, but it is more costly to maintain, because the system cannot be mechanized and must be worked and picked by hand.
Cordon training is another type of spur pruned system. Here the spurs are spread out along a horizontal cordon and are trained up wires (vertical shoot positioning). This type of training does allow for mechanization, and is very widely used in California and other New World areas. It is also used for Pinot Noir in the Champagne region.
 Guyot training is a head trained, cane pruned system, where one to four canes from the growth of previous year is tied down to a support wire, and the buds along these canes send out the shoots, which are then trained on wires. This system is most often used in cooler regions where shading the grapes can prevent their ripening, and the vines are exposed to the danger of mildew and rot.
It is also during dormancy that pre-emergent herbicides are traditionally applied by growers who use this technique, although some leave grass or other cover crops. Cover crops prevent erosion, help build the life of the soil, and prevent compaction of the soil from the use of tractors. Cover crops are not practical, however, in regions where they would take too much water and too many nutrients away from the vine.
Organic and biodynamic growers who work the soil to remove weeds will do so at this period, often using a horse instead of the tractor (which can damage the soil by compacting it and impeding the flow of air and water).
Prior to flowering, any earth that had been mounded up around the vine to protect it during the winter is removed. At this same period, growers who use bugs to fight other bugs will release them into the vineyard at this point, and organic and biodynamic growers who rely on copper and sulfur sprays to combat rot will begin to spray at this time.
After flowering, the vine and the fruit continue to grow and develop. During this period, the main responsibility of a grower is to protect his crop from pest and disease, including rot and mildew. Growers who practice sustainable agriculture will spray for rot and mildew only as needed, and not on a predetermined schedule. Growers who employ traditional fungicide practices, however, will spray on a regular schedule between June and three weeks before harvest.
Each grower will decide the treatments that he feels are necessary for his vineyard, and these will continue throughout the summer. It is easier for growers in warm climates to operate with fewer chemicals, since the climate is not conducive to rot and mildew. In addition, smaller growers face fewer economic risks than larger ones, and are not subject to stockholder demands. It is common for the larger companies to “play it safe” and spray on a regular schedule, although some of the largest companies, such as LVMH, are now doing all they can to limit synthetic inputs into the environment.
In addition to fungal diseases such as rot and mildew, viral diseases like leafroll and fan-leaf and bacterial infections such as Pierce’s Disease (PD) can also cause problems in the vineyard. Viral diseases slow yield but do not kill a vine, but PD is almost always fatal.
In addition to disease there are a host of pests, some of which can be treated, and others that cannot. Among the most difficult to treat are phylloxera and nematodes. These are small aphids that infect the roots of the vines, causing damage and killing the vine eventually. They originated in North America, where the indigenous species of vine developed tolerance to them. The fine wine grapes of Europe, however, had not, and were thus killed when the pest was introduced into European vineyards during 19th century horticultural experimentation.
Besides phylloxera and nematodes, grape moths and spider mites are common pests that can severely damage vines, but they can be treated much more easily. Other pests consume the fruit, such as birds, rabbits and deer.
 In addition to these standard practices, several other treatments may be used. One of the most frequently used is irrigation. Irrigation is widely practiced in many New World winegrowing regions, although it is illegal in most of the Old World. The reason for this lies not in the innate virtue or sinfulness of adding water, but in the traditional rainfall patterns throughout the world. In areas where rain falls throughout the year, such as Europe, irrigation is not normally essential, and could be easily abused to achieve higher yields. In many parts of California and Australia, grape growing would not be possible at all without irrigation, because the rainfall is insufficient and falls in the winter.
Mulch is another optional practice. Some growers use organic matter (manure or straw) to enrich the soil and nourish the microorganisms in the soil. This can lead to problems with rot and mildew, however. Plastic sheeting is another type of “mulch” that is less romantic, but still sometimes used. Plastic strips stop the evaporation of water and the absorption of unwanted rain. It also warms the soil and thus helps roots develop.
Canopy management is a general term that refers to a variety of practices that together are intended to lighten the foliage or canopy and allow for more air circulation and more light to reach the grapes. One important advocate of these techniques is Dr. Richard Smart. Dr. Smart is a viticulturalist from New Zealand who is famous for his work “Sunlight into Wine”. In this work he champions the idea that growers can improve quality and increase volume at the same time by maintaining a proper balance between the canopy, the fruit and the vine.
There are several different effects of canopy management on the vine. If not done too severely, it will increase photosynthesis because shaded leaves in the interior of the canopy use more sugar than they create. Because of increased photosynthesis, more sugar is created. At the same time, there is lower acidity, since vine respiration increased in leaves exposed to the sun. At the end of the day, yield per vine increases as it is exposed to more sunshine. This is because more clusters develop, because cluster weight is higher, and because of the increase in photosynthetic activity.
At the same time that the amount of foliage is being managed, the other half of the equation often is being adapted at the same time. This is the process of “green harvesting” (vendage vert) or “dropping fruit” that is often discussed. The aim is to remove fruit, lessening the overall fruit load and potentially improving the quality of that which remains. Some growers, however, believe that it is important to regulate fruit load with winter pruning, and that green harvesting creates imbalance in the vine. It is certainly true that the vine will compensate for any fruit removed before veraison by increasing bunch weight, thus negating the effect of the procedure.
At the end of the day, the strategies that a grower chooses can be characterized is several different ways. So called “traditional viticulture” nourishes a vine through the use of fertilizers and takes preventative action against rot and disease by spraying on a regular schedule. Growers who subscribe to the notions of “sustainable agriculture” or “lutte raisonnée” are opposed to massive chemical treatments, and act in a reactive way to threats rather than spraying on a schedule. The amount of each treatment is also limited to the smallest possible amount. “integrated pest management” or “lutte integreé” takes this approach further, and uses non-chemical means such as predator bugs wherever possible to fight against pests. Organic viticulture opposes the use of synthetic fertilizers pesticides and herbicides. The rules for organic production are dictated separately in each wine producing country.
Organic growers see the soil as a living world, and do their best to preserve this life. They do allow, however, the use of sulfur and copper spray in the vineyard which do not decompose in the soil. The same is true of biodynamic growers. Biodynamic growers take organic viticulture one step further, and see wine production as integrated into the motion of the universe as a whole. Accordingly, they time their movements according to the stars, and make every effort to respect the mysterious forces of nature. While organic rules are legally defined and administered, however, those of biodynamic growers depend only on the certifying bodies such as Demeter and Biodivin.
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Wine Regions of the World
