6 - Vineyard Management Flashcards
What are three categories of considerations a grape grower thinks about when choosing a grape variety?
- environmental conditions - what is site’s average temperature, rainfall and sunlight hours? what is fertility of soil and drainage? this influences choice of grape variety and ideal planting density and training and trellising
- business considerations - proximity of a vineyard to the utility infrastructure (power and water etc), availability of workers, accessibility of machinery and cost of land
- grape variety - whether variety suits climactic conditions. whether there is demand for grapes. there may be legal restrictions
What are the two main categories of vine training (refers to shape of the permanent wood of the vine)?
Head training (vines with relatively little permanent wood. can be spur pruned or replacement cane-pruned) Cordon training (trunk with one or more permanent horizontal arms or 'cordons') vines are usually spur pruned. this method makes mechanization in the vineyard easier.
both can be low-trained to benefit from heat retained by soil, or high-trained to avoid frosts
what is the removal of unwanted leaves, canes, and permanent wood?
pruning
when does pruning take place? what is the purpose of pruning?
winter and summer.
Winter pruning determines number and location of buds that will form shoots in the coming growing season. ensuring buds are not too close together helps with the canopy management
what are the two types of winter pruning?
spur pruning: spurs are short sections of one-year-old wood, cut down to only two to three buds. used on headtrained or cordon trained.
replacement cane pruning: canes are longer sections of one-year-old wood. 8-20 buds. only one or two canes are retained, each tied horizontally to trellis. most often seen on head-trained vines. usually seen on headtrained vines
True/false: summer pruning involves trimming canopy to restrict vegetative growth and direct sugar production to grape (instead of shoots and leaves). also involves leaf stripping so grapes optimal sunlight exposure.
True.
why would a vineyard use untrellised vineyards?
the vines without trellis hang down often as far as ground. the extra shade helps protect grapes in warm or hot, dry sunny regions.
this training system is sometimes called gobelet.
what is canopy management?
row of vines requires a line of posts joined by horizontal wires. the canes and shoots are then tied to trellis.
what are the 3 main reasons for trellising/canopy management?
- control sunlight that gets into canopy. depending on amount of sunlight available, an open canopy maximizes grape exposure to sunlight. on other hand, keeping grapes shaded prevents sunburn which can lead to off-flavors.
- open canopy promote circulation and avoid fungal disease in wet climates.
- trellising helps mechanisation. Positioning grapes in one area of vine, and leaves in another makes this easier
Vertical Shoot Positioning (VSP) is the most widely used system of trellising
True. VSP can be used with replacement cane or spur pruned vines. Shoots are trained vertically and tied in place onto trellis. this system keeps shoots apart and makes canopy open, well aerated and shade free
How might VSP be adapted in hot conditions?
the top of shoots are not tied in, they flop over to offer some shade. this way, unlike an untrellised bush vine, mechanical harvesting can be used.
What are two main factors that influence planting density?
limited water availability - if there is low rainfall or limited access to irrigation, lower planting density can be helpful (vines don’t have to compete with other vines for water)
low levels nutrients and rainfall - a vine can thrive in barely fertile soil and will grow lots of vegetative growth instead of fruit. to counteract this, vins planted at high density to create competition for resources among roots which restricts vegetation. pruning to leave correct # of buds is important. combination density and pruning.
high levels of nutrients and sufficient rainfall - very fertile soils are not suitable for viticulture. in New World where soils have more nutrients, high-density planting is not enough to limit growth of vines. Often use low-density planting with vines with multiple cordons or canes.
How are yields measured?
amount of grapes produced. measured in terms of weight (tonnes per hectare) or volume (hectolitres of wine per hectare)
What are risks associated with green harvesting? why is it carried out?
it is carried out to manage high yields. immature grapes are removed after veraison.
risks: if done at wrong time, vines compensate by increasing size of existing grapes and dilute flavors in grapes and return yield to previous size.
What are common pests in vineyard and how can they be prevented?
phylloxera: insect that attacks roots - can be prevented with American rootstocks
nematodes: microscopic worms that attack vine roots and can trasmit viruses. sanitising soil before replanting and using resistant rootstocks can help prevent them.
birds and mammals: can eat a lot of grapes. half-eaten or crushed grapes lead to fungal disease. netting protects against birds, and fencing deters mammals
insects: feed on grapes and leaves. insecticides or integrated pest management can be used (predators of pests encouraged to live in vineyard)
