Vine training
Additional benefits of utilizing particular training systems could be to control potential yields and to facilitate mechanization of certain vineyard tasks such as pruning, irrigation, applying pesticide or fertilizing sprays as well as harvesting the grapes.
[3] Pruning refers to the cutting and shaping of the cordon or "arms" of the grapevine in winter which will determine the number of buds that are allowed to become grape clusters.
[4] In some wine regions, such as France, the exact number of buds is outlined by Appellation d'origine contrôlée (AOC) regulations.
During the summer growing season, pruning can involve removing young plant shoots or excess bunches of grapes with green harvesting.
As research in this area continued into the 21st century, new vine training systems were developed that could be adapted to the desired wine making style as well as the labor needs and particular mesoclimate of the vineyard.
[1] While the most pertinent purpose of establishing a vine training system is canopy management, especially dealing with shading, there are many other reasons that come into play.
Vines that are trained to have their "fruiting zone" of grape clusters at waist to chest height are easier for vineyard workers to harvest without straining their bodies with excessive bending or reaching.
Similarly, keeping the fruiting zone in a consistent spot on each vine makes it easier to set up machinery for pruning, spraying and harvesting.
[4] Through photosynthesis, less than 10% of the full sunlight received by a leaf is converted into energy which makes obstacles such as shading even more detrimental to the plant.
During the annual growth cycle of the grapevine, excessive shading can reduce the success rate of bud formation, budbreak, fruit set as well as the size and quantity of grape berries on a cluster.
In wet, humid climates poor air circulation can promote the development of various grape diseases such as powdery mildew and grey rot.
The latter method requires more labor-intensive trellising and training for Vitis vinifera vines which are naturally more inclined to grow upwards rather than down.
A vine is described as "vigorous" if it has a propensity to produce many shoots that are outwardly observable as a large, leafy canopy.
The ability of the grapevine to support such a large canopy is dependent on the health of its root system and storage of carbohydrates.
In the 1950s, Austrian winemaker Lenz Moser advocated the high-culture style of training, recommending low density plantings of vines with trunks 4 ft (1.25 m) high.
The vine is pruned down to the spur in winter, leaving only one strong cane which is then trained into becoming the main branch for next year's crop.
[1] Within these larger classifications, the vine training system may be further distinguished by the canopy such as whether it is free (like goblet) or constrained by shoot positioning along wires (such as VSP trellising) and whether it includes a single curtain (Guyot) or double (Lyre).
