As mentioned in last week's Ontario Farmer potash deficiency symptoms are showing up many soybean fields. You do not have to drive very far to see lots of examples.
Many farmers just assume the drought was too severe and the plants are starting to ripen. The reason for the deficiency showing up now is because potash demand peaks during the pod fill stage. Most assume there is nothing they can do. Very few farmers actually ask about potash deficiency. Take a close look at your fields.
If you see symptoms that look like this you have potash deficiency. There are two main reasons for the symptoms to appear. Either the soil has low potash reserves to begin with or the ground is so compacted the plant cannot forage for the available potash in the soil. Most of the time in our neighbourhood it is caused by low potash reserves in the soil. It is a worry that despite spending big dollars on land purchases and rent, farmers are not keeping up with basic soil maintenance. The solution is simple, but you have to get off your wallet one more time.
A good explanation on the benefit of potash and phosphate applications in soybeans from the University of Wisconsin can be found at the following link.