Transforming agriculture: Drug discovery methods improve nitrogen fertiliser use efficiency

Researchers in the School of Chemistry have used a drug discovery-based approach to develop promising new nitrification inhibitors that improve nutrient uptake by plants during nitrogen fertilisation.

Nitrogen fertiliser, the most widely used fertiliser nutrient globally, costs farmers around $450 billion per year. While critical for plant growth, unfortunately 50-80 per cent of nitrogen applied to crops is lost during production, with ammonia emissions polluting the atmosphere, nitrate runoff leading to water pollution and nitrous oxide emissions contributing to global warming.

^{Drug delivery methods are being used to improve nitrogen fertiliser use efficiency}

To support more efficient farming and reduce losses to the environment, the ARC Research Hub for Smart Fertilisers recently funded research on nitrification inhibitors (NIs), which target ammonia monooxygenase (AMO), the enzyme responsible for oxidising ammonia. By inhibiting AMO, NIs increase the retention time of ammonia, reducing nitrogen losses through nitrate leaching and nitrous oxide emissions. Using NIs is a recommended strategy by the Intergovernmental Panel on Climate Change to address low nutrient update by plants. However, only three NIs are currently commercially available, of which none exhibit a reliable efficacy irrespective of the agricultural setting

In the research, a team of chemists led by Professor Uta Wille introduced substituted triazoles – compound structures widely used in new drug discovery – as promising new NIs. Specifically, 4-methyl-1-(prop-2-yn-1-yl)-1H-1,2,3-triazole (MPT) stands out as an efficient inhibitor of ammonia monooxygenase. In soil tests, MPT effectively retains ammonium, and reduces nitrate and nitrous oxide formation, especially in acidic soils where the current commercial NIs struggle (Figure 1). Most importantly, ecotoxicity tests on various species showed no harm from MPT.

This is an exciting advancement in the development of ‘smart’ fertilisers that support more efficient farming, and the School of Chemistry looks forward to continued collaboration with interdisciplinary research teams.