In response to producer questions about phosphorus (P) fertilizer needs for corn, a state-wide project was initiated in 2001 targeting high and very high soil test P sites and monitoring silage yield and quality when grown without starter fertilizer, without P in the starter, and with P banded at two levels. In general, for applied research and extension to be trusted and have positive impact, we realized that stakeholders must play key roles in the process, from start to finish. To meet the challenge, a network of Cornell University faculty and staff, 14 Cornell Cooperative Extension field crop educators, 46 farmers, and 7 agri-service providers formed to perform 75 on-farm trials and 13 research station experiments in 22 counties across New York State from 2001 through 2003. The project was branded the New York Starter P Project. Interest was further generated by active discussion of the project at Empire Farm Days, local on-farm field days, winter meetings and Certified Crop Advisor trainings, and through extension articles, postcards and the Nutrient Management Spear Program web site (http://nmsp.css.cornell.edu/projects/starterp.asp). The multi-site, multi-year study showed a significant yield response to a modest P application (<28 kg P2O5/ha) for soils testing high in P without recent manure applications whereas no yield or quality benefits were obtained on high P soils with manure recent applications or soils testing very high in P regardless of manure history. Planting date and soil type did not impact the results. To quantify the impact of the project, an extensive survey was conducted to assess management changes. Thanks to the integration of applied research and extension and the involvement of many stakeholders, responses indicate that fully 18% of the producers who heard about the project were convinced to reduce their starter P applications on corn.