The discussion and guides that follow are oriented toward the central U.S. Corn Belt, but are relevant to other cropping systems with similar crop geographies. They are provided to assist in fertilizer nitrogen (N) management decisions that will help lessen the impact of fertilizer N use on greenhouse gas (GHG) emissions and help mitigate the global warming potential (GWP) - expressed as CO2 equivalent. The three GHGs of interest to agriculture are: nitrous oxide (N2O), methane (CH4), and CO2. The GWP of CH4 is 23 times greater and the GWP of N2O is 296 times greater than that of CO2. Because fertilizer N use may be associated with N2O emissions, and because the GWP of N2O is so much greater than CO2, fertilizer N BMPs to reduce N2O emissions are emphasized in this practical guide. For example, fertilizer N BMPs which help minimize excess nitrate (NO3 -) in the soil during warm, wet, or waterlogged conditions can result in lowered risks for N2O emission.
