Nitrogen shares in global environmental impacts and crop production
The increased use of nitrogen (N) fertilizer and emissions of reactive N compounds (Nr) from agriculture, food consumption and combustion of fossil fuels, constitute one of the largest global environmental problems. The N-shares in world regions for impacts of ambient air pollution and human health range between 5 and 60%, for impacts on terrestrial biodiversity between 1 and 17% and on global warming around 2-3%. However, Nr use in fertilizer is also a major factor for increased crop productivity, with N-shares ranging between 10 and 55% for major food crops in world regions.
Nr impacts human wellbeing and ecosystems in many ways. The contribution of the Nr load to impacts – the Nshare – is a useful metric to communicate the relevance of N pollution and mitigation (Erisman et al., 2013).