Our nitrogen 'footprint': the need for increased crop nitrogen use efficiency

Abstract

Nitrogen (N) is an essential element for the growth and development of all living organisms, as it is a constituent of DNA, RNA, ATP and protein. In plants, N is also an essential component of other key compounds including chlorophyll, auxin, cytokinins, alkaloids and glucosinolates. Plants are the ultimate source of N and carbon for all animals including humans (Shewry, 2009; Halford et al., 2011). Despite the importance of N in metabolism, it is present in short supply in forms that can be assimilated by a plant, and as a result, low soil N availability is often the major nutrient factor limiting the growth and yield of crops.