This article highlights revisions to Iowa State University (ISU) soil-test interpretations and application guidelines for phosphorus (P), potassium (K) and lime in an update of extension publication PM 1688 "A General Guide for Crop Nutrient and Limestone Recommendations in Iowa." The printed version of this publication will not be ready until later in the fall and the online version should be posted by early October at the Extension Online Store and on the Soil Fertility web site. Field research is conducted continuously to assure that nutrient management suggestions are up to date. This research has indicated that some recommendations should not be changed, but other recommendations needed significant change to optimize nutrient management to improve the profitability and sustainability of crop production.