In the last 60 years fertiliser use in agriculture has increased by 900%. However, it’s been reported that up to 80% of these fertilisers are not utilised by crops but are lost to the environment as nitrous oxide, ammonia and nitrate. Improving nitrogen use efficiency is recognised as one possible solution to reducing the sector’s environmental impact and optimising its productivity and sustainability in the face of increasing pressure to feed a growing population. Improving nitrogen use efficiency in crop production reviews recent advances in understanding nitrogen cycling in soil and best practices to assess crop nitrogen status, such as the use of proximal sensors and remote sensing techniques. The book considers developments in the use of inorganic nitrogen fertilisers and their effectiveness in optimising nitrogen use efficiency, as well as how more organic sources of nitrogen, such as livestock manure, can be optimised to achieve the same goal.