Chapter 3 - The Growing Environment - Part 2 Water & Nutrients Flashcards
Why do vines need water?
Photosynthesis
Turgidity (so it doesn’t wilt)
Regulating temp
Acts as solvent for nutrients in the soil
When is it most important to have water stress?
Pre-verasion
What can too much water late in the ripening period cause? Too little?
Grape dilution
Grape splitting
Grape shrivel
Not reaching desired level of ripeness
What does hail do?
Damages the green parts of the vine
The amount of water available to the vine depends on:
How free-draining the soil is
Water-holding properties of the soil - function of the soil’s texture and organic matter
Soil depth
Why are waterlogged soils dangerous to vines?
Reduces amount of o2 available to the roots
Evapotranspiration Rate defn and what is it dependent on
The amount of transpiration from teh vine, combined with the evaporation fo water from the soil surface AKA the rate at whcih water is no longer availble
It is dependent on temp, humidity, and wind
Nitrogen
Major impact on vine vigor and grape quality
Component of proteins and chlorophyll
Too much nitrogen: causes excessive vegetative growth, hindering ripening and excessive shading
Too little nitrogen: reduvrd vigor and yellowing of vine leaves
Overall, want a restricted supply of nitrogen for higher quality grapes
Potassium
Helps regulate the flow of water in the vine
Too much potassium in soil: causes problems with magnesium update, reducing yield and ripening. Increases grape pH
Too little potassium: low sugar accumulation in the grapes, reduced yield and poor vine growth
Phosphorus
Important for photosynthesis
Only a small amount needed
Too little phosphorus: poory developed root system, reduced vine growth, lower yields
Calcium
Important role in the structure of plant cells and in photosynthesis
Too little calcium: negative affect on fruit set
Magnesium
Found in chlorophyll - imp for photosynthesis
Too little magnesium: reduced grape yields and poor ripening
How does organic compounds become useful?
It is not readily useable by the vine
Organisms that live in the soil mineralize the organic compound into inorganic compounds (can also transform it into humus)
Soils that can hold high levels of nutrients:
Clay soil
Soils with humus
Plain/valley floor soil (compared to slope soil)
Most important physical elements of soil: (and describe)
Texture - the proportioons of mineral particles of sand, silt, and clay
Clay: finely textured bc very small, large SA:volume so very effecient at holding water and nutrients
Sand: relatively large and small SA: volume - limited capacity at holding water and nutrients and drains easily. More workable and easier for roots to grow thru
Structure - how the mineral particles form aggregates
High clay content are sticky and can form aggregates that are hard for vine roots to penetrate and hard to cultivate
Sand soil and larger are loosely structured and may need clay or humus to help bind them together
