1. Evaluation of Soil Test Potassium Guidelines in Minnesota

Changes in corn and soybean potassium guidelines in states in the Upper Midwest have resulted in questions from consultants and farmers as to how best to manage the nutrient. In Iowa, soil samples analyzed on a field moist basis have been suggested as a method to predict the amount of potassium required for corn and soybean production while in North Dakota the ratio of illite to smecite in soil samples is utilized to determine the appropriate critical level to determine where potassium fertilizer... D. Kaiser, L. Leverich-nigon