D1: growing environment nutrients 6 Flashcards
Nutrients are important for healthy vine growth and can have an influence on yield and grape composition.
1) vine require low lvl of nutrients (so most soils are able to sustain vine growth)
2) soil nutrients are depleted (uitgeput) by viticulture, so monitoring is important before it leads to any deficiencies
The most important nutrients are:
1) nitrogen
2) Potassium
3) Phosphorus
4) Calcium
5) Magnesium
Nitrogen:
1) essential for vine growth (vigour and grape quality)
2) it is a component of proteins and chlorophyll (required for photosynthesis)
3) too much can cause excessive shoot growth
* sugars being diverted to the growing shoots and leaves rather than the grapes
* causes big canopy
4) low levels: reduces vigour and yellowing of vine leaves
*** good level result in high quality grapes
Potassium:
1) helps regulate the flow of water in the vine
2) very high levels can cause problems in the uptake of magnesium — reduced yields and poor ripening
3) high potassium in soil leads to high potassium levels in grape
* high potassium level in grape must are linked to high ph
4) low levels can lead to low sugar accumulation in the grapes, reduced grape yields and poor vine growth in general
Phosphorus:
1) important for photosynthesis
2) only a small amount needed, and enough present in soil usually
3) a deficiency leads to poorly developed root systems (and hence a diminished ability to take up water and nutrients
Calcium:
1) important role in the structure of plant cells and in photosynthesis
** deficiency is rare but have an negative influence on fruit set
Magnesium:
1) magnesium is found in chlorophyll and therefore has a key role in photosynthesis
** deficiency can result in reduced grape yields and poor ripening
Nutrients dissolve in soil water, which is then taken up by the roots of the vine so soil factors that influence water availability also impact nutrient availability:
true
Iron is poorly available in soils with high ph (soils with high proportion of calcium carbonate such as limestone and this can cause:
chlorosis
chlorosis:
Leaves turn yellow and photosynthesis stops
so graperipening and yields are negativelly affected
Organic nutrient compounds found and added to soils (eg in the form of manure or compost) are not available in the form that the vine can take up and need to be converted into inorganic compounds:
in this context organic matter contains carbon , inorganic generally describes compounds that do not contain carbon
Mineralisation:
Organisms that live in the soil (bacteria fungi eartworms,…) are important in this process
* feeding on the organic matter and converting it into available forms
** organic matter can be converted by these organisms into either humus or inorganic nutrient compounds
soil with high proportion of clay are good at holding nutrients, whereas sandy soils are poor at holding nutrients
Humus can increase the soila ability
Soils on slopes are often thinner and less fertile than those on plains or valley floors
true
Soil is the upper layer of earth and typically made of geological sediment,
Organic remains in the form of humus and the poors in between the sediment that contains water and air