A method of fertilizing and/or irrigating a field with water containing potassium bisulfate is disclosed. The method includes adding a predetermined amount of potassium bisulfate to irrigation water for the field, and delivering the mixture of potassium bisulfate and irrigation water to the field. Alternatively, the method may provide potassium bisulfate to crops by applying or spreading the potassium bisulfate onto ground near or proximate to the crops, and allowing water to carry the potassium bisulfate into the ground.