SDSU Extension 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 mean soil test level 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 listed in each crop nutrient recommendation section and summarized in Table 3.
Statements that clarify or modify the recommendations are listed in each crop nutrient recommendation section.
The Fertilizer Recommendations Guide (formerly EC750 by Jim Gerwing and Ron Gelderman, 2005) is the source for soil fertility recommendations in South Dakota.