Water is necessary for life, and fertilizer runoff from agricultural sites can result in the contamination of water systems. This contamination can be a significant health risk for any population depending on those systems. To protect the public, it is necessary to limit fertilizer runoff. This may be achieved in part by persuading farmers to adopt innovative fertilizer management practices. This project examines the 4R Nutrient Stewardship Program, a public communication campaign seeking to encourage changes in fertilizer application behaviors with the goal of reducing runoff. The campaign was created and is operated by the Fertilizer Institute, a multistate trade association, in cooperation with the International Plant Nutrient Institute. This campaign is operated primarily to prevent the introduction of new policies regulating fertilizer use. Because this campaign constitutes an industry response to potential adverse policy creation, it is appropriate to regard the 4R Nutrient Stewardship Program as a strategic issues management campaign. The focus of this investigation is the 4R Nutrient Stewardship Program's effort to persuade Ohio farmers living and working within the area of the Maumee River Watershed to adopt new practices. The Maumee River Watershed is a critical water system in Ohio that drains 5,024 square miles and flows through all or part of 18 Ohio counties (Ohio Environmental Protection Agency, 2018a). The 4R Nutrient Stewardship Program is approached as an issues management campaign targeted to farmers, fertilizer retailers, policymakers, and policy advocates. This examination is informed by diffusion of innovations theory (DOI), a framework describing the process whereby a community adopts a new innovation (Rogers, 2003). When a public communication campaign seeks to encourage behavioral change, the principles of DOI can directly inform campaign design and analysis. By illustrating the process of diffusion, DOI can answer questions about how strategic messaging decisions influence behavioral change across targeted populations. In some cases, the diffusion of an innovation may serve as strategy for managing issues faced by an organization or an industry. The goal of this project is to demonstrate the utility of DOI in case studies of public communication campaigns seeking to encourage behavioral change within target audiences. Doing so will broaden the utility of this theory in a way that will inform both campaign scholarship and design. Findings from this research will be useful in design for future campaigns seeking to change fertilizer application behaviors to protect water systems. To demonstrate the utility of DOI in these contexts, survey data collected from farmers within the Maumee River Watershed in Ohio are used to examine the 4R Nutrient Stewardship Program campaign. The survey data were collected by The Ohio State University's College of Agriculture, Food and Environmental Sciences and is used here with permission. The data are analyzed to determine rates of understanding about 4R inn...