NEW RESEARCH from the a project including the University of Reading shows that higher plant diversity in farmland grass increases yields, reducing farmers’ reliance on nitrogen fertiliser.
It was the key finding of an international study led by Trinity College Dublin with contributions from Professor Chris Reynolds at UoR.
The research, published this week in Science, shows that under warmer temperatures, the yield benefits of more diverse grasslands increase further.
Scientists say 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, and the combined yield was much greater than the sum of each species grown alone.
Sowing two grasses, two legumes and two herbs in roughly equal proportions can optimise both yield and nitrogen saving benefits
The six species mixture produced on average 12.3 tonnes per hectare per growing season – an 11% increase compared to grass alone (which used more than double the nitrogen fertiliser), and an 18% increase compared to the two species grass legume combination
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.”
