Assessing N Management Strategies Using Comet-Farm.

Nitrogen management is one of the strongest ‘levers’ that farm and ranch managers have to increase productivity and economic returns.   However, key environmental externalities, such as impacts on water quality and greenhouse gas (GHG) emissions are also highly dependent on N use and management.  How GHG emissions, including N2O, will be influenced by different N management decisions is particularly difficult for land managers to access because of the complexity of multiple on-farm emission sources and the many factors that influence them.   COMET-Farm is a comprehensive farm/ranch full GHG inventory platform that can be used to assess the current GHG footprint of one or more agricultural operations and to evaluate a variety of potential management alternatives to reduce GHGs.  Examples of using the system for evaluating N management alternatives, involving mineral fertilizers, manure and other organic N amendments,  for cropland scenarios and for integrated cropland and livestock systems are given.