Potassium and Alfalfa

Potassium is essential to maintain a good stand of alfalfa.  Alfalfa removes 50 pounds of potassium per ton.  Dr Miller used to say to shoot for 9 tons per acre, so you are going to need 450 pounds of potassium per year or 750 pounds of potassium fertilizer.  Sounds like a lot.  The soil does release some potassium each year, but I would not count on that with soil tests.  If you decide to skimp on potassium grass will take over your stand and protein content of your hay will drop. 

The good news is that cattle manure is high in potassium, so you can put it back on the field.   If you do not like manure on your hay, use it to maintain the crop fields and use what you save to fertilize the alfalfa.