In Ohio, phosphorus (P) and potassium (K) recommendations for corn and soybean were last updated in 1995 with the Tri-State Fertilizer Recommendations. Water quality and nutrient management issues in the state have stimulated interest in re-evaluating these recommendations after more than two decades. From 2014-2018, we conducted 102 on-farm trials in P in corn and soybean and 84 trials in K for corn and soybean in Ohio.
Soil Science Extension
University of Wisconsin Madison