Manganese (Mn)
Function: assists the transformation of nitrogen and the assimilation of other elements to
form sugars and proteins, and in respiration.
Indicator plants: cereals, especially oats (causing Grey Speck disease), beans, chickpeas,
peas (causing Marsh Spot disease), vegetables, radish, beet (causing Speckled Yellows)
and fruit trees.
Symptoms: as above, and leaves are chlorotic; new leaves mottled (D). Stunted plants
(D & E).
Remarks: symptoms are most marked in neutral or alkaline soils which are high in
organic matter, but it is also harmful in acid soils (D & E). If in excess, Manganese
scorches the root system, which develops poorly (E).
Molybdenum (Mo)
Function: in nodulation of legumes and in the reduction on nitrates.
Indicator plants: soybeans, lentils, brassica (especially broccoli and cauliflower, causing
Whiptail), spinach, oats, citrus and pasture.
Symptoms: stunted plants. Leaves are chlorotic, droop at the tips & curl inwards (D).
Remarks: occurs in both acid and alkaline soils, but the cures are different (D & E).
Less available in acid soils.
Boron (B)
Function: assists growth by contributing in the metabolism of Calcium. Also assists
nodulation in legumes.
Indicator plants and Symptoms: vegetables (distorted leaves - D), soybeans (leaves
shrivel and fall off - E), sugar beet (Heart Rot - D), swedes and turnips (Brown Rot - D),
cauliflowers (become brown - D), celery (leaves are distorted, stems are cracked - D),
root crops (hollow or rotten roots which turn grey and mushy in the middle. Leaves
distorted - D) and citrus fruit (lumpy fruit - D).
Remarks: less available to plants in alkaline soils. Boron deficiency is common in sandy
soils. Boron should be applied with care as there is only a small margin between
deficiency and excess.
Iron (Fe)
Function: in the formation of chlorophyll and enzymes (eg respiratory) and in the
metabolism of nucleic acid.
Indicator plants: sorghum, barley, cauliflower, citrus and peach.
Symptoms: leaves are chlorotic and often striped or mottled (D & E). With citrus plants
the leaves remain green.
Remarks: iron is less available in alkaline soils and soils high in Copper. Symptoms are
similar to toxicities of Copper, Zinc and other elements.
Copper (Cu)
Function: in photosynthesis, enzyme systems and Vitamin A formation.
Indicator plants: maize, cereals, vegetables, leaf crops, tobacco, avocado and fruit trees.
Symptoms: small or shrivelled grain in cereals. Leaves chlorotic and curled, and
margins scorched. Multiple buds formed (D & E).
Remarks: not seen very often, but can occur after excessive lime applications. Soils take
years to recover from copper toxicity.
elle
(Elle)
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