The impact of fertilization and hydrology on nitrate fluxes from Mississippi watersheds

► Fertilizer inputs predict stream fluxes of nitrogen better than discharge or NANI in the MRB. ► Ag practices that co-vary with fertilizer input decrease residence time and nitrogen removal. ► A large fraction of fertilizer input is rapidly transported to rivers on average to wet years. ► There is a greater amount & proportion of water originating from highly engineered cropland watersheds. ► Managing fertilizer, cropping systems, and hydrology is paramount to decreasing N loads.