An in situ study of inorganic nitrogen flow under different fertilization treatments on a wheat-maize rotation system surrounding Nansi Lake, China

•Nitrogen loss in runoff was primarily nitrate-nitrogen.•In leachate, nitrogen loss was equal parts nitrate-nitrogen and ammonium-nitrogen.•Runoff accounted for more than two-thirds of inorganic nitrogen loss through water.•Using control-release nitrogen fertilizer would decrease nitrogen loss.•Incorporation of wheat straw to the soil would decrease nitrogen loss.