Magnesium for crop production | UMN Extension
There are fertilizers that are a combination of potassium sulfate and magnesium sulfate. The Mg content is 11 percent. The sulfur (S) concentration is 22 percent and the K 2 O percentage is 22 percent. This fertilizer is easily used in a starter fertilizer for corn or as a Mg source when there is no desire to increase soil pH.