05 Jul 2011

Nutrient Deficiencies in Canola Crops

BCG Expo, July 2011

Key to Generalised Nutrient Deficiency Symptoms in Crops
Color Change in Lower Leaves (Translocated Nutrients)
Plants small with light green or light yellow color… older leaves yellow (chlorosis) first…yellowing begins at leaf tip and extends along midribs in corn and sorghum.
Plants dark green with purple cast…leaves and plants small.
Yellow/brown discoloration and scorching along outer margin of older leaves…begins at leaf tip in corn and sorghum.
A pale green discoloration near the leaf tip… becomes bright yellow between veins, finally reddish-purple from edge inward.
Color Change in Upper Leaves (Nutrients Not Translocated) Terminal Bud Dies
Emergence of primary leaves delayed… terminal buds deteriorate. Leaf tips may be stuck together in corn.
Leaves near growing point yellowed… growth buds appear as white or light brown dead tissue.
Terminal Bud Remains Alive
Leaves, including veins, turn pale green to yellow… young leaves first.
Pronounced interveinal chlorosis on citrus and bronzing of leaves. On corn, broad white to yellow bands appear on the leaves on each side of the midrib. Plants stunted, shortened internodes. New growth may die in some bean species.
Chlorosis first appears in young leaves at the tips of the shoots, the leaf color changes uniformly to yellow, with the exception of the veins, brown spot or dead tissue appears when severely deficient.
Leaves yellowish-gray or reddish-gray with green veins, marginal and interveinal chlorosis, the chlorotic leaves retain their normal shape.
Young leaves uniformly pale yellow, or may wilt and wither without chlorosis. In small grain cereal crops there can be clustered growth, twisted younger leaves with necrotic tips, lodging and accompanied by poor seed set in heads.
Wilting of upper leaves followed by chlorosis. In small grain cereal crops there may be chlorotic progressing to necrotic spots on leaves on some varieties.
Young leaves wilt and turn necrotic along margins. Chlorosis of older leaves due to inability to properly utilize nitrogen.

Remember: Deficiency symptoms are not often clearly observable. Masking effects from other nutrient deficiencies, disease or insect infestations, or weather stresses (drought, flooding, or temperature) can prevent accurate visual diagnosis of nutrient deficiencies.
Remember: Deficiency symptoms always indicate severe deficiency and may not be at all observable if there is only a shortage or minor lack of a specific nutrient.
Canola & Nutrient Deficiencies.pdf (size: 1.62 MB)

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