Corn and Soybean Grain Yield Response
to Different Phosphorus Fertilization Rates
and Soil-Test Phosphorus Levels
Is Version Of
Phosphorus (P) fertilization is needed for profitable crop production in most Iowa soils. Extensive research has been conducted for decades on crop yield response to P and calibration of soil-test P methods. Frequent changes in crop genotypes and increasing yield levels necessitates continuous research to revise and update management guidelines as needed. This report summarizes results of a multi-year experiment conducted to evaluate corn and soybean grain yield response to different P fertilization rates and soil-test P levels.