Proper soil pH and fertility are essential for profitable forage production. Adequate levels of phosphorus and potassium are needed for high yield and persistence of legumes, especially alfalfa. Forage fertilization should be based on soil-test levels and realistic yield goals.
Take a soil test to determine soil pH and nutrient status at least six months before seeding. This allows time to correct deficiencies in the topsoil zone.
Make sure to request the current Tri-State Fertilizer Recommendations (Ohio-Michigan-Indiana) from your soil testing lab, or use the soil recommendation spreadsheet listed below to check the values. Some other recommendations are too high, particularly for potassium, which could result in animal health problems from high potassium levels in the forage.
Under hayland management, forages should be topdressed annually to maintain soil nutrient levels. Each ton of tall grass or legume forage removes approximately 13 pounds of P2O5 and 50 pounds of K2O.