The goal of this paper is to review some of the soil fertility research projects I have contributed to and to make some comments about what results were successful and what areas have continuing research and education needs. In general, the purpose of much of this work was to create new knowledge and build upon existing information to provide a sound science base for nutrient management guidelines and recommendations for producers and the industry. In fact, many of the projects were initiated to answer questions or solve problems brought to our attention by farmers and the agricultural industry. The maintenance of a credible science base supporting nutrient management recommendations is made even more important when these recommendations are widely used as the basis for nutrient management regulatory policy.