Nitrogen and humanity: a perpetual crisis

Nitrogen is vitally important in raising agricultural production but, the drive for yield alone, has led to very high application rates of nitrates at the farm level resulting in groundwater contamination and eutrophication of rivers, lakes and estuaries. Reactive nitrogen in the biosphere has doubled from pre-industrial levels, primarily through massive inputs into agriculture, and Nitrate Vulnerable Zones now cover 55% of England’s landscape. The atmospheric concentration of nitrous oxide, which is around 300-times more potent than CO₂ as a greenhouse gas, continues to rise each year.

These are problems of regional, national and international scope that require urgent attention and are at the forefront of the grand challenges for UK and global science. An alternative to added nitrogenous fertilizer is biological nitrogen fixation from legumes. Understanding the biochemistry and genetics of how bacteria, called rhizobia, infect legumes to induce formation of N₂-fixing nodules is a focus of our group.

How we might deploy them more effectively to help ameliorate the nitrogen crisis will be discussed.