Nitrogen footprints: Regional realities and options to reduce nitrogen loss to the environment

Hideaki Shibata, James N. Galloway, Allison M. Leach, Lia R. Cattaneo, Laura Cattell Noll, Jan Willem Erisman, Baojing Gu, Xia Liang, Kentaro Hayashi, Lin Ma, Tommy Dalgaard, Morten Graversgaard, Deli Chen, Keisuke Nansai, Junko Shindo, Kazuyo Matsubae, Azusa Oita, Ming-Chien Su, Shin-Ichiro Mishima, Albert Bleeker

Nitrogen (N) management presents a sustainability dilemma: N is strongly linked to energy and food production, but excess reactive N causes environmental pollution. The N footprint is an indicator that quantifies reactive N losses to the environment from consumption and production of food and the use of energy. The average per capita N footprint (calculated using the N-Calculator methodology) of ten countries varies from 15 to 47 kg N capita(-1) year(-1). The major cause of the difference is the protein consumption rates and food production N losses. The food sector dominates all countries' N footprints. Global connections via trade significantly affect the N footprint in countries that rely on imported foods and feeds. The authors present N footprint reduction strategies (e.g., improve N use efficiency, increase N recycling, reduce food waste, shift dietary choices) and identify knowledge gaps (e.g., the N footprint from nonfood goods and soil N process).