In recent decades, information communication has been identified as an important factor facilitating farmers to adopt agricultural beneficial or best management practices (BMPs) to improve water quality. The purpose of the study is to develop a mobile GIS application to facilitate communications of BMP economic cost and environmental effectiveness information in agri-environmental programs. At the first step, a framework was developed to define the required information content and how information should be produced and disseminated. Second, the framework was implemented to develop an open-source mobile GIS application for Android operating systems with the Gully Creek watershed of southern Ontario as the case study area. The system or interface has two main modules: One is to examine the cost and effectiveness of user-defined BMP exploratory scenarios and the other is to define BMP policy/management scenarios in which optimized BMP types and locations are identified based on environmental targets or financial constraints.