Iron deficiency chlorosis

Iron deficiency chlorosis: biology

Iron is an essential micronutrient for plant health and growth, playing a role in the synthesis of chlorophyll and chloroplast maintenance. When available iron is limited or deficient, overall plant health suffers with Iron Deficiency Chlorosis (IDC).

Most Canadian Prairie soils have good levels of iron. However soil carbonate content can inhibit a plant’s ability to take up the iron, and this is compounded by soluble salts.

AGVISE Laboratories has created a chart which shows the risk of severity of IDC:

In wet springs or in heavy clay fields such as the Red River Valley of Manitoba, soil saturation can limit iron solubility. Excess nitrates and root rot can also intensify the effects of IDC.

Chlorosis exhibits as a gradual yellowing between the leaf veins. Veins remain green. In more severe stages of chlorosis, entire leaves can turn yellow, and leaf margins turn brown, brittle and die.

In soybeans, symptoms of iron deficiency chlorosis typically appear in the second and third trifoliate stage, when iron reserves in the seed are depleted. Fields will appear yellowed overall. Under severe conditions, if the growing point is injured yield loss can occur. NDSU research has shown that there is a strong relationship between the severity of chlorosis at the 5-6 trifoliate stage and final yield.¹