Nitrogen Efficiency in Agricultural Soils

Nitrogen Efficiency in Agricultural Soils - D.S. Jenkinson

Nitrogen is a major nutrient, essential for all living organisms. Although it is the main constituent of the air, N availability is the main limiting factor for productivity of terrestrial ecosystems, including agroecosystems. That N is one of the most important inputs in crop production is well documented by the existence of a billion € fertilizer industry. The economic importance of N has been identified already more than 100 years ago (Löhnis 1913). Our modern society would not exist without the invention of technical creation of reactive N, used to fertilize agricultural land in order to ensure food security for the growing global population (Erisman et al. 2008). On the one hand, the application of fertilizer in excessive amounts leads to environmental problems, such as eutrophication of waters, loss of biodiversity, global warming and stratospheric ozone depletion, often found in high-income areas. In fact, the costs of environmental N pollution are exceeding the added value due to N fertilization (Sutton et al. 2011b). On the other hand, limited access to mineral fertilizers leads to low yields and insufficient food supply, in many low-income areas (Sutton et al. 2011a). Worldwide, researchers are tackling the problems of how to improve soil fertility and N management for different type of climates, soils and crop conditions around the world. This includes increased yields, increased N use efficiency (NUE) and reduced losses to the environment in the short- and long-term.