Changes in runoff chemistry and soil fertility after multiple years of cattle winter bale feeding on annual cropland on the Canadian prairies

•Feeding cattle hay bales on cropland during winter months increases soil fertility.•Export and concentration of N & P in snowmelt runoff are elevated after bale grazing.•Elevated concentrations in runoff of P, but not of N, persist in non-grazing years.•N & P runoff loss per animal unit day is similar for bale grazing & confined feeding.•Changing timing and siting of bale grazing will reduce discharge and nutrient export.