Cover crops play an important role in managing nutrients and water quality. When planted on time, cover crops can recover much of nitrogen loss from field. Delayed planting can reduce nitrogen recovery and thereby increase nutrient pollution from agriculture. Optimal planting decisions depend on accumulated Growing Degree Days (GDD) which varies with geographic location. Identification of optimal planting dates can enable farmers to improve nutrient status of the farm while minimizing water quality impacts. In regions where water quality impairment is significant, substantial reduction in nutrient loading can be achieved through careful planning. There is an increasing need to provide timely information to farming community at a site-specific level. This study is an effort to use web-based mapping and landscape interface (like Google Earth) to process geographic information on optimal cover crop planting to farmers and conservation agents.

The web-based tool is capable of displaying a geographic area using online mapping services with overlay capability, access to real-time weather, and field mapping capabilities. Site-specific information can be visually identified or queried by farmers. The web application can present GDD-based recommendations along with suggestions on potential nitrogen losses from delayed planting. Other features of the tool

The GDD analysis is based on daily time series information from meteorological stations in the Commonwealth of Massachusetts. The calculations of all stations are spline interpolated and accumulated to develop continuous information and used in the development of the Zonal model. Local variation in GDD resulting from changes in elevation is assessed in the Local model. A Hybrid model uses both regional and local predictions in developing planting recommendations.

The web-decision model can be a valuable tool to farmers in mitigating nutrient losses and in reducing agricultural nonpoint source pollution.