More plant types in grassland boost crop yields

Higher plant diversity in farmland grass increases yields, reducing farmers' reliance on nitrogen fertiliser.

That is the key finding of an international study led by Trinity College Dublin with contributions from Professor Chris Reynolds at the University of Reading.

The research, published this week in Science, shows that under warmer temperatures, the yield benefits of more diverse grasslands increase further. This highlights how mixing multiple plant species could help farmers adapt to rising temperatures driven by climate change.

Researchers at 26 international sites, including in Reading, carried out an experiment across different climates and conditions. They tested whether adding more plant species – up to two grasses, two legumes (clovers or similar plants), and two herbs – could maintain or improve yields while reducing reliance on nitrogen fertilisers, which harm the environment when overused.

The results showed that these plant mixtures achieved high yields because different plants worked together. Grasses combined with legumes, and legumes with herbs. The combined yield was much greater than the sum of each species grown alone.

The findings align with results from the University of Reading's Diverse Forages project, which found that multispecies swards without nitrogen fertiliser produced as much or more forage as single grass types receiving 250 kg of nitrogen fertiliser each year.

Professor Chris Reynolds, from the University of Reading's School of Agriculture, Policy and Development, said: "This study shows farmers can produce more food while cutting fertiliser use. That matters for farm economics and for the environment. The findings hold across Europe, North America and Asia, which means this can make a difference at scale for grasslands that feed livestock and support food production worldwide."

This research is part of the LegacyNet network, an international collaboration examining how managing grasslands affects both forage production and the yield of cereal crops grown afterwards.

Finn, J. A., Malisch, C. S., Suter, M., Meyer, S. T., Peratoner, G., Thivierge, N., Abalos, D., Adler, P. R., Bezemer, T. M., Black, A. D., Ergon, Å., Golińska, B., Grange, G., Hakl, J., Hoekstra, N. J., Huguenin-Elie, O., Jing, J., Jungers, J. M., Lajeunesse, J., . . . Brophy, C. (2025). Multispecies grasslands produce more yield from lower nitrogen inputs across a climatic gradient. Science. https://doi.org/ady0764