Iron Deficiency Chlorosis

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Iron deficiency symptoms in soybean. Photo © Edwin J. Penas and Richard A. Wiese, University of Nebraska

Iron deficiency chlorosis (IDC) is a physiological disease caused by a lack of iron in the soybean plant. There are soybean producers throughout the North Central region that identify chlorosis as an important production issue in their fields, resulting in substantial yield losses in some years.

Iron is necessary for the formation of chlorophyll, which is the green pigment in plants. When the amount of iron available to plants is inadequate for normal growth, leaves become pale green, yellow or white, particularly between the veins. This loss of green color is called chlorosis. The effect of chlorosis on the plant is reduced growth and yield.

Iron deficiency chlorosis and soil conditions

Most soils contain abundant levels of iron. However, at high soil pH (greater than pH 7.5), iron is not soluble and cannot be absorbed by plant roots. Iron in this form will not be available to the plant unless soil conditions change.

Chlorosis of soybeans does not occur on all high-pH soils. Even within a field with high pH soil, areas of chlorotic and nonchlorotic soybeans can be found. Researchers have noted that conditions in the subsoil may vary. Subsoil in areas with chlorotic soybeans are often poorly drained, higher in pH, higher in soluble salts and in excess lime (carbonates) compared to areas where soybeans do not have IDC.

Information on these pages is from the cooperative effort of researchers throughout the North Central states. Information from this site can be copied and distributed for educational use. Please credit the source with our name and URL: NCSRP Plant Health Initiative at www.planthealth.info. Please do not use copyrighted photos without permission.