Approved work: The impacts and costs of synthetic fertilisers

Synthetic fertilisers have a significant environmental impact on water quality through leaching; air quality through ammonia emissions; and climate change through nitrous oxide emissions; as well as GHG emissions arising from the fossil fuels used in their manufacture.

Various approaches are being developed to reduce over application, such as smart sensing and precision application technologies, but a wider circular economy of soils has been proposed. This includes alternative feedstocks being processed to provide nitrate and phosphate fertilisers, such as sewage and animal manures. In Denmark, on farm nitrogen quotas and the near total use of available organic manure has reduced demand for inorganic fertiliser by 50%. Other approaches have been commercialised include manipulating plant-soil microbiome interactions, such as inoculating cereals with nitrogen-fixing rhizobacteria to promote plant growth, with more advanced technologies such as genetically editing plants to stimulate beneficial microbes and using synthetic biology to enhance microbial inoculants under development.

This POSTnote will summarise the challenges and opportunities for the different approaches for reducing the use of synthetic fertilisers.

Work on this briefing will commence in mid-September 2023.

Image by: (© By Надежда Урюпина – stock.adobe.com)