Grain Crops Extension

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K Deficient Soybeans

Soybeans in many fields across Kentucky are expressing symptoms of potassium deficiency. Excessive soil moisture, soil compaction and low levels of potassium are possible causes. Soil tests should be conducted this fall to determine nutrient levels. More information about soil testing is available from the UK Soil Testing website.

Photos below show some of the symptoms and field conditions that can lead to K deficiency.

Soil compaction can lead to K deficiency. The roots in this image are growing parallel to the soil surface, instead of down through the soil . . . indicating a compaction layer at about 1-inch depth.

Symptoms of K deficiency include yellowing (chlorosis) from the leaf edge to the center of the leaf. As the yellowing moves to the center of the leaf, the margin will begin to turn reddish brown.

K deficiency symptoms expressed in rows of soybeans.

Symptoms of K deficiency: a closer look.

Healthy soybeans can be seen at the back of this field. The K deficiency symptoms are occurring in an area of the field where frequent equipment traffic occurred.

Symptoms of K deficiency: a closer look.

Symptoms of K deficiency: a closer look.

Symptoms of K deficiency: a closer look.