The Effect of Chelated Iron on Bean Plants

Symptoms of Iron Chlorosis in Beans

• Beans exhibit a variety of symptoms when suffering from a deficiency in iron. Younger leaves show the most intense chlorosis. The new leaves that unfold are yellow, almost white. Another way to determine if your bean is suffering from a lack of iron is to pull one plant out of the soil and inspect the roots. Affected roots appear brown and have a distinct odor to them. Healthy roots are white.

Causes of Iron Chlorosis in Beans

• Iron chlorosis is caused by the lack of available iron for uptake in the soil profile. Iron is a metal cation that precipitates, or forms solids, when joined with soils high in oxygen, hydrogen and carbonates. High pH soils contain a large amount of calcium carbonate (lime) due to the lack of precipitaion to wash or leach out this naturally occuring mineral. High pH soils often bind the iron up, making it unavailable for your beans to use to form chlorophyll.

Chelated Iron

• "Chelation" comes from the Greek word "chele," or claw. Chelation is a holding of a metal ion, such as iron, between two or more atoms of a single molecule. This protective "claw" keeps the iron from forming a solid, and keeps it soluble in water. This solubility makes the iron available for use by your beans, and keeps your beans dark green and healthy in high pH soils. Chelated iron can be purchased as a foliar spray or in powder, tablet or granular form.

Effects on Beans

• When using a chelated iron on your beans, newer leaves are darker and growth accelerates. If you apply your chelated iron with a foliar spray, the iron is absorbed directly into the leaf and used to increase production of chlorophyll. Chlorophyll plays an important role in photosynthesis and energy production. When a plant is deficient in iron, it indirectly affects the growth rate of the plant.