I have been out looking at some soybean fields and have started to see some potassium deficiency in some fields. Every year I see some fields with potassium deficiency in our sandy soils in the south. It is not uncommon to see in double crop beans where the straw is baled. Potassium deficiency is seen as yellowing or browning and sometimes necrosis along the edges of older leaves. As the deficiency becomes more severe the symptoms move higher up the plant. Below is a picture of potasium deficiency in soybean. Potassium deficiency should not be confused with manganese deficiency. With manganese deficiency the veins of the leaves remain green.