D6: Managing Nutrients and Water Flashcards
Define the term ‘soil health’
- ability of soil to support vine, enabling it to grow and produce fruit
Includes:
- structure of soil
- amount of organic matter and humus in soil
- number of living organisms in soil
- total amount of available nutrients that a vine needs to grow
What is the impact of poor soil health?
- can cause problems with availability and uptake of nutrients and water from soil
- impacts on vine quality and ripening
What three nutrients does the soil need?
- nitrogen
- phosphorous
- potassium
Does need some other nutrients but these are the three main ones
- direct application
- promotes biological activity and soil structure
- mgmt of weeds/plants which compete for nutrients
What are the benefits of removing weeds?
- ‘bare, moist soils’ absorb heat during the day and release heat at night to reduce risk of frost
What are the negatives of weeds?
- can increase frost risk
- make it difficult for machinery to get through vineyards
When might fertiliser be used, and what are the pros and cons of it?
- may be added before planting to help growth of young vines
- corrects nutrient deficiencies
- can lead to excess vigour and an unbalanced vine
What are the two types of fertiliser?
- organic
- mineral
What is organic fertiliser?
- fresh, composted or animal material (e.g. manure or slurry)
- green manure = cover crops mown into soil to decompose
POSITIVES
- slow distribution of nutrients to vine
- cheap and free
- good for soil structure and water retention
- give nutrition for soil organisms
NEGATIVES
- bulky and expensive to transport and spread
- need incorporating into soil so labour intensive
What is mineral fertiliser?
- extracted from ground or chemically manufactured
- single or several nutrients
POSITIVES
- can be tailored to vine needs
- more concentrated, cheaper to transport and distribute
NEGATIVES
- no benefit for soil organisms
- does not improve soil structure
- more expensive than organic fertiliser
What is Cultivation, and what are the benefits and negatives?
- ploughing soil to cut or distribute weeds root system
POSITIVES
- doesn’t use chemicals
- can be biodynamic and organic
- fertiliser enabler
NEGATIVES
- damage soil structure and destruction of habitats
- costly as requires labour and machinery
- buries seeds and therefore encourages weeds to grow back
- can increase vine vigour too much
Define Herbicides and name three types which are typically used
- chemical sprays which kill weeds
PRE-EMERGENCE HERBICIDES
- sprayed before weeds established
- absorbed by weeds roots
- inhibit germination of young seedlings
CONTACT HERBICIDES
- sprayed on established weeds - kill green parts of weeds they contact
SYSTEMIC HERBICIDES
- sprayed on established weeds
- taken in by leaves
- herbicide travels up and down weed in sap and kills whole plant
What are the positives and negatives of using herbicides?
POSITIVES
- cheap
- high effective
- less damaging to soil in terms of cultivation
NEGATIVES
- can be damaging to operator, consumer, environment etc
- not good for vineyard ecosystems
- weeds can become resistant (e.g. GLYPHOSATE in South Africa - overused and now ryegrass is resistant)
- can increase vine vigour too much (no competition for water or nutrients)
*not allowed in organic or biodynamic viticulture
What are the positives and negatives of ‘animal grazing’
POSITIVES
- doesn’t use chemicals
- organic and biodynamic
- manure producing
- meat for humans
NEGATIVES
- risk to vines so need to be trained high
- labour intensive
- susceptible to vineyard pesticides
What are COVER CROPS and what are the positives and negatives of cover crops?
- plants which are specifically planted that have a benefit to the vineyard
- legumes (beans, clover)
- cereals (ryegrass, oats)
- all matched to the vineyards needs
- can use natural vegetation but don’t have that level of control
POSITIVES
- suppress weeds
- no chemicals
- green manure key for fertilisation
- improve soil structure
- compete for water and nutrients (requires careful management so don’t compete at key points in vine cycle)
- manage soil erosion
- enhance biodiversity and is both organic and biodynamic
- give surface to drive on
NEGATIVES
- difficult to mow under rows so has time and labour implications
- can’t use on steep slopes
- need to be careful that doesn’t compete for all the nutrients and water as can have a detrimental affect on the vine
What is mulching and what are the positives and negatives?
- spreading of matter on vineyard soil to suppress growth of weeds
POSITIVES
- biodegradable (straw or bark chips)
- provide nutrients for vine and humus
- biodynamic/organic/non-chemical
- reduces water evap from soil
NEGATIVES
- bulky and expensive to transport and spread
- need thick layer to be effective
- can increase vigour too much as no competition for water or nutrients
What impact does the amount and timing of irrigation have on vine cycle?
- significant impact
- particularly on growth and ripeness
Irrigation
- should be considered as part of design of vineyard
- better to do initially as laying pipes later can be disruptive
- some EU GIs do NOT permit irrigation (or only in some circumstances)
- water use tightly regulated in many countries
What are four of the possible water sources for a vineyard?
- river
- lake
- borehole
- reservoir
How can you improve efficiency of water use?
- water-efficient irrigation systems and techniques
- drought-tolerant grapes (e.g. grenache) and rootstocks (e.g. 140R)
- reducing evaporation (e.g. through mulching)
- reducing competition (e.g. removing weeds)
- increasing humus levels to improve retention
- promoting growth of deep roots
Name three countries which have recently had water shortages
- Australia
- California
- South Africa
Why is water quality so important?
- need to filter before it is used or else can block up sprinkler systems
- high salinity (e.g in Australia) can increase salt in soil and makes it difficult for vine roots to take up water so vine dehydrates, wilts and dies
- big issue for drop irrigation as salt accumulates at roots rather than being washed deeper into soils like in flood
What are the four different types of irrigation systems?
- drip
- flood
- channel irrigation
- overhead sprinklers
DRIP IRRIGATION
- most common
- drippers positioned far enough away from vines to encourage roots to grow and seek out water
POSITIVES
- economic use of water
- control water supply to individual rows or blocks
- can supply fertiliser (liquid) - called fertigation
- can be used on slopes
NEGATIVES
- expensive to install
- need clean water or else drippers become blocked
- can be blocked by algae, bacteria or minerals/salts
- can’t be used for frost protection
FLOOD IRRIGATION
- water stored behind sluice and floods vineyard at scheduled time
POSITIVES
- cheap to install and maintain
NEGATIVES
- inefficient as vine doesn’t take up a lot
- only use on flat/gentle slopes
CHANNEL IRRIGATION
- water flows down furrows dug between vine rows
- used in Argentina (lots of water from Andes)
- not suitable if only limited supply of water
OVERHEAD SPRINKLERS
- showers water over vineyard
- expensive to install and maintain as need high water pressure
- use lots of water (vs drip)
- can be used as frost protection
Why would you want to put the vine under water stress?
- good between fruit set and veraison
- encourages development and ripening
What is ‘regulated deficit irrigation’ (RDI)?
- timing and regulating irrigation so vine is mildly stressed for specific time in growing season
- between fruit set and veraison to limit shoot growth and encourage grape development
- uses dripper system
- best in regions with dry growing season and sandy/loam soils that dry out and can be rewetted quickly
POSITIVES
- good to help control vine growth and grape development
- uses less water
- good for black grapes as reduces grape size, increases proportion of skin to juice and increases concentration of anthocyanins and tannins
NEGATIVES
- prolonged or extreme stress can impact yield and quality
- expensive as need to put in equipment to monitor and respond to levels of moisture in soil
What is ‘dry farming’?
- no irrigation
- refers to not using irrigation in areas with limited rainfall in growing season
- lower yields but improvement in grape quality
Why is drainage important?
- if soils are suitably free draining, can cause problems
- would need to install artificial drainage systems
- expensive - but better to be done at outset of vineyard development
- gives healthier, better balanced vines - better for ripening
- aids mechanisation (can get machinery on soils)
What might areas with higher rainfall do differently?
- leave natural vegetation to encourage competition
- improve soil structure and remove plough plans to regulate water drainage
