Plant Nutrition Flashcards
Describe a range of nutrients required for plant growth
MAJOR - required by the plant in a large amounts:
Nitrogen Phosphorus Potassium Calcium Magnesium
MINOR - required by the plant in much smaller amounts. Also known as trace amounts:
Iron
Role of Magnesium and signs of deficiency
ROLE OF MAGNESIUM:
- Required for photosynthesis as central component of chlorophyll
- Activates certain enzymes
- Involved in the movement of phosphorus in the plant
SIGNS OF DEFICIENCY:
- Intervein chlorosis on older leaves first
- Leaf tips curl upwards
- Early leaf fall
Role of Nitrogen and signs of deficiency
ROLE OF NITROGEN:
- Shoot and leafy growth
- Constituent of chlorophyll, proteins, hormones and nucleic acid
SIGNS OF DEFICIENCY:
- Slow spindly growth
- Chlorosis - general yellowing of oldest leaves first
- Reduced growth rate and stunting
- Small flowers and fruit
Role of Calcium and signs of deficiency
ROLE OF CALCIUM:
- Required for activity in meristems particularly in root tips
- Constituent of cell walls middle lamella as calcium pectate, binding cells together
SIGNS OF DEFICIENCY:
- Weakened cell walls mean inward curling in young pale leaves
- Tissues die
- Cupping and burning of leaf tips with blackening of young leaves. E.g. Blossom end rot in tomatoes and bitter pit in apples
Role of Phosphorus and signs of deficiency
ROLE OF PHOSPHORUS:
- Essential in seeds for germination
- Promotes root growth
- Required for photosynthesis, nitrogen fixation, crop growth, produce quality and root development
- Component of molecules involved in energy transfer in cells (ATP) and genetic material (DNA)
SIGNS OF DEFICIENCY:
- Poor seedling growth
- Poor root growth
- Purpling/blueing of older leaves
- Delayed and small fruit growth
Role of Potassium and signs of deficiency
ROLE OF POTASSIUM:
- Promotes flowering and fruiting
- Regulate functioning of stomatal guard cells
- Essential for photosynthesis
- Importance in disease resistance
- Increases hardiness against cold and drought
- Increases scent
SIGNS OF DEFICIENCY:
- Poor quality fruit and seeds
- Leaf scorch
- Leaves bronze and curl inwards and downwards
- Necrosis: dead patches on leaves, particularly the margins of older leaves
Role of Iron and signs of deficiency
ROLE OF IRON:
- Required in chloroplasts as part of photosynthesis
SIGNS OF DEFICIENCY:
- Yellowing between veins of younger leaves then to older leaves
- Failure to flower and fruit
Describe what is meant by the pH terms
Definition of pH:
- Expresses the amount of acidity or alkalinity in the soil in terms of hydrogen ions concentration
- a measurement of the balance between acidity and alkalinity with a growing media
Scale: 0-14
Below 7 is acidic
7 is neutral
Above 7 alkaline
What is pH range found in garden soils
Approximately 4-8
Why is 6.5 the most suitable pH for a wide range of plants in the British Isles
This range provides the the plant with the maximum availability of the most nutrients
What is the standard way to raise pH?
Adding lime
To surface of the soil in the form of calcium carbonate (ground limestone) in autumn
Do not manure at same time
What are the effects of soil pH on soil structure and nutrient availability?
SOIL STRUCTURE: Soil organisms: - worms prefer neutral to slightly limy - bacteria are more plentiful in neutral soils - fungi prefer acidic to neutral soils
Crumb Formation:
- Lime causes flocculation (grouping together of clay particles) thus improving structure - crumb formation
NUTRIENT AVAILABILITY:
- In highly acidic soil, aluminum and manganese can become more available and more toxic to a plant while calcium, phosphorus, and magnesium are less available to the plant.
- In highly alkaline soil, phosphorus and most micronutrients (trace elements) become less available.
- Lime-induced chlorosis, or leaf yellowing, is caused by strongly alkaline soil, which can make iron or manganese unavailable to plants.
What is flocculation?
Grouping together of individual clay particles making soil less dense
Materials used to influence soil pH?
Sulphur - lowers
Lime - raises
Organic materials
Benefits and limitations of each material used to influence pH
LIME BENEFITS
- Raises pH
- Provides calcium
- Encourages worm population
- Discourages some diseases such as clubroot in brassicas
- Makes clay soils workable by flocculation
- Can make other nutrients available
LIME LIMITATIONS:
- Sandy soil will revert back to being more acidic quickly
- Lime may burn foliage
SULPHUR BENEFITS:
- Lowers pH
- Cheap
SULPHUR LIMITATIONS:
- Can take weeks to take effect and can be months in winter
ORGANIC MATERIALS BENEFITS:
- Improves soil structure
- effective over a long period
ORGANIC MATERIALS LIMITATIONS:
- Slow effect
- May have P&D
- Bulky
Name 3 Calcifuges
Lime hating plants - need acidic soil:
- Rhododendron ponticum
- Camelia japonica
- Pieris japonica
- Vaccinium corymbosum
Name 3 plants suitable for neutral pH
- Malus domestica
- Cucumis sativus
- Daucus carota
Name 3 Calcicoles
Lime loving plants - need alkaline soil
- Clematis montana
- Agapanthus africanus
- Fagus sylvatica
- Syringa vulgaris
What is meant by fertiliser?
Concentrated source of nutrients added to growing media
Which nutrient is most likely leached from soil and therefore needed to be replace
Calcium. Free draining sands in areas of high rainfall will lose their Calcium ions rapidly and such soils will easily become acidic
Characteristics of organic and inorganic sources of nutrients
Organic nutrients (=carbon containing)
- Derived from living organisms
- Often consist of waste products
- Usually contain trace elements
- Can be some variability
Inorganic nutrients
- From non living materials
- Most artificially made
- Some, like ground rock, are suitable in an organic system
What is meant by “Soluble Fertiliser” and give example
- Dissolve immediately with water
Example: Ammonium sulphate
What is meant by “Slow Release Fertiliser” and give example
- Don’t dissolve immediately with water but provide nutrients in soluble form over a long period of time.
Example: Bone meal
What is meant by “Straight Fertilisers” and give example
- Supplies one major nutrient
Example: Ammonium sulphate (N)
What is meant by “Compound Fertiliser” and give example
- Supplies 2 or more nutrients
Example: Growmore 7:7:7 NPK
What is meant by “Controlled Release Fertiliser” and give example
- Fertilisers held within a permeable resin coating which is released at a rate dependent on moisture and temperature
EXAMPLE: Osmocote
What is meant by “Base Dressing” and when would you apply it?
MEANING:
- Fertiliser added to an incorporated into a growing medium prior to planting.
- They are frequently used to supply nutrients over a long period so are often compound and slow release
APPLIED:
- Domestic Gardens dug in before sowing/planting
What is meant by “Top Dressing” and when would you apply it?
MEANING:
- Added to surface of soil/compost, possibly working in gently
- They can be quick or slow release
- Used to maintain nutrient levels in permanent/long term plantings and rely on irrigation/rain to deliver nutrients to the roots
APPLIED:
- When nutrients are needed after plants are established e.g lawns in autumn
What is meant by “Liquid Feed” and when would you apply it?
MEANING:
- Fertilisers dissolved and watered onto soils
- Top dressings where dry fertilisers would be less appropriate
APPLIED:
- Hanging baskets pot plants
- Houseplants where nutrients are required quickly
What is meant by “Foliar Feed” and when would you apply it?
MEAINING:
- Fertilisers used to correct imbalances/deficiencies rapidly so could be straight (Epson salts to supply magnesium) or compound (Seaweed to act as a tonic)
- Liquid feed diluted sufficiently so can be watered onto leaves without damaging/scorching
- Immediate uptake
APPLIED:
- Routine
- First thing in morning
Comparison of organic matter to fertilisers
OM bulky F concentrated
OM low nutrient content F high
OM imprecise control F precise control
OM slow effect F quick effect except slow release
OM effective over long period F effect may be quickly lost
OM improves soil structure F no impact on soil structure
OM will contain pests and diseases F no pests and diseases
Describe construction of a compost heap
AEROBIC (Hot heap)
- Material added all at once
ANAEROBIC (Cold heap)
- Material added gradually as it becomes available
ESTABLISHMENT
- Position in a sheltered area away from wind, orientated away from heat e.g. south and west
- To be constructed on bare soil, wooden sides, cover to keep excessive rain off, compost heap to be minimum size of 1m3, material to be layered inside the compost heap.
- Make rodent proof
- Easy access
- Consider visual concerns
CHOICE OF MATERIAL:
- Green material (nitrogen rich):
Suitable materials include vegetable peelings, shredded prunings, herbaceous material, newsprint, tea leaves, animal manure
Avoid: perennial weeds/seeds/diseased/cooked material/coloured magazines/toxic manures
- Woody material can be shredded first for quicker breakdown.
Suitable materials: plant stems, woody twigs, straw, newspaper, corrugated cardboard.
Avoid any material treated with herbicides or that is affected by pests and diseases.
RATIO:
- Mixture of soft green: sappy, nitrogen rich and brown: woody, carbon rich material
Ratio: 2 thirds brown 1 third green
- No material of the same type should be added in a layer of more than 15cm.
AERATION:
- Air should be allowed through the base and the sides of the heap
- Turn regularly to allow air to penetrate and to give micro organisms the oxygen they need to break down the material
- Air is introduced by turning the heap. After 4 turnings heap is left to mature
- Anaerobic requires no turning other making sure materials around the edge are mixed into the middle
MOISTURE CONTENT:
- The plant material within the bin should always be moist and so the bins should be watered in dry conditions. Water can be applied with a can or hose
- Do not allow to become waterlogged
LIME:
- Depending on the ingredients lime may need to be added especially with an anaerobic heap where a lower pH may be generated
pH:
- Brandling worms are likely to be present and would appreciate a higher pH from liming
TEMPERATURE:
- A minimum of 65 degress is required to kill a range of weed seeds and fungal spores
INSULATION:
- Insulate both heaps
- Anaerobic - plastic cone popular
ACCELERATORS:
- Compost activators are not usually required if there is a good balance of material volumes
- To aid breakdown processes tiger or brandling worms can be added
- Powders/granules can be used
VOLUME:
- Fo aerobic a minimum of cubic metre
DEVELOPMENT:
- Start the filling of each bin with a woody layer as this will improve the bins’ drainage and aeration potential
- Add as much material as possible in any one go thoroughly mixing the green and brown materials
- Turn the compost heap regularly by turning the outer edges into the centre to ensure that all the material can become hot
- Once the material has rotted down to form a dark, crumbly texture the compost is ready to use
Name 2 organic fertilisers
Seaweed Liquid comfrey Nettle feed Poultry manure pellets Fish blood and bone Bonemeal
Name 2 inorganic fertilisers
Miracle-Gro
Sulphate of Potash
Growmore
Sulphate of Ammonia
Describe the influence of nitrogen, potassium and phosphorus on plant growth and development
Nitrogen: Leafy growth, needed in proteins, DNA, chlorophyll
Potassium: Fruit and flower growth, hardiness, stomatal opening
Phosphorus: Root growth. ATP (respiration)
State the benefits and limitations of nutrient sources
BENEFITS (Organic):
- They are oftne waste materials
- Good range of nurients including trace elements
- Most will deliver nutrients gradually
LIMITATIONS (Organic):
- Sometimes the content is variable
- There is possible contamination e.g. slaughterhouse products
- Availability can fluctuate
BENEFITS (Non-organic):
- Often cheap
- Can be made easy to apply in regular shaped granules
- Specialist such as controlled release
LIMITATIONS (Non-organic):
- A lot of energy can be used in their manufacture
- Control release has a plastic polymer covering which releases the nutrients when the moisture and temperature levels are correct for the target plant to be in active growth. Can cause problems in very warm Springs resulting in quicker release than intended or in colder late Springs causing a delay.
- Trace elements are frequently excluded
- Quick release can cause pollution problems
