South Dakota Fertilizer Rate Guidelines Calculator for Corn, Soybean, and Wheat

Extensive research has been conducted to develop fertilizer recommendations for crops grown in South Dakota. To calculate nitrogen (N) fertilizer rates the equation uses the factors yield potential, lbs N/bu of crop multiplier, preplant soil test N to a depth of 0 to 24 in., previous crop, manure application, and tillage type. To calculate phosphorus (P) and potassium (K) rates the equation uses the factors of soil test P (Olsen-P or Bray-1 P extraction tests) or soil test K (ammonium acetate extraction test) at a depth of 0 to 6 in. and yield potential. To calculate sulfur (S) fertilizer rates, the equation uses the factors of soil test S to a depth of 0 to 24 in. soil texture category and tillage type. This workbook has been developed to aid in the ease of calculating fertilizer rates (N, P, K, and S) for corn, soybean, and wheat. Future updates of this workbook will work to include other crops grown in South Dakota.