Nutrients, pH & fertiliser revision Flashcards
What is Nitrogen (N) for?
Strong vegetative growth
Key component of DNA/RNA & proteins
Key component of chlorophyll
(Most limiting element)
What is Phosphorus (P) for?
Respiration and metabolism
Component of DNA, sugars, phosphates
(Second most limiting element)
What is Potassium (K) for?
Stomatal regulation
Osmotic regulator of guard cells
Activates many enzymes
(Likely limiting factor, after N & P)
What is Calcium (Ca) for?
Cell wall structures
What is Magnesium (Mg) for?
Chlorophyll
What is Iron (Fe) for?
Chlorophyll and respiration
Symptoms of Nitrogen (N) deficiency:
Stunted growth
Chlorosis (older leaves first)
Symptoms of Phosphorus (P) deficiency:
Stunted new growth
Weak, poor root development
Older leaves turn purple-green
Symptoms of Potassium (K) deficiency:
Older leaves scorched and curl
Poor fruit/flower development
Symptoms of Calcium (Ca) deficiency:
Localised tissue necrosis
Necrotic leaf margins (younger leaves)
Death of terminal buds & root tips
Symptoms of Magnesium (Mg) deficiency:
Interveinal chlorosis (older leaves first)
Leaves may fall early
Symptoms of Iron (Fe) deficiency:
Interveinal chlorosis (younger leaves first)
Soil pH effects on nutrient availablilty:
Acid soils are deficient in Phosphorus
Alkaline soils are deficient in Iron
Alkaline soils cause lime-induced chlorosis, due to lack of Iron
Why should the pH of a soil be considered?
Micro-organisms less prevalent in acid soils
Earthworms prefer neutral-alkaline soils (not acid!)
Iron less available in alkaline soils
Calcifuges like more acid soils
Calcicoles like more alkaline soils
Availability of nutrients in soil depends on the pH.
Certain diseases more prevalent in low pH soil - e.g. Club Root in brassicas.
Which materials make soil more acid?
Peat
Green manures
Bark
Conifer needles
Ammonium sulphate (Sulphur)
