soil test, nitrogen, phosphurus, potassium
Cooperative Extension Service, U.S. Dept. of Agriculture, South Dakota State University
South Dakota State University Soil Testing Lab fertilizer recommendations are based on field research in South Dakota and neighboring states. However, information from outside this region is used where only limited local data was available. The tables were developed as part of continuing cooperation between these states to standardize recommendations across the three-state area. The recommendations in the tables are generated by equations and, therefore, change consistently across yield goals and soil test levels. Due to space limitations, only the recommendations for selected yield goals and the soil test level at the center of each soil test range (very low, low, medium, high, and very high) have been printed in this guide. Where specific yield goals and/or soil test values are not listed in the table, recommendations can be determined by interpolating between the nearest two yield goals and soil test levels. In addition, recommendations for nitrogen, phosphorus, and potassium also can be calculated using the equations at the bottom of each table. These equations are summarized in Table 3. Recommendations reported by the SDSU Soil Testing Lab are rounded off to the nearest 5 lb per acre.
Gerwig, Jim and Gelderman, Ron, "Fertilizer Recommendations Guide" (2005). SDSU Extension Circulars. 431.