Increasing plant diversity in agricultural grasslands boosts yields, reducing reliance on fertiliser

Higher plant diversity in agricultural grasslands increases yields with lower inputs of nitrogen fertiliser. Under warmer temperatures, the yield benefits of more diverse grasslands further increase. There are headline results from a landmark study across 26 international sites as part of LegacyNet, and published in Science. 

Sown productive grasslands (used to supply forage for livestock or as a ley in a crop rotation) typically comprise low species diversity. Two widely used grassland practices comprise 1) a single grass species (monoculture) managed with high inputs of synthetic nitrogen fertiliser, and 2) a two-species grass-legume combination that receives lower inputs of nitrogen fertiliser.

Multi-species swards: more forage with less fertiliser, and more resilient to drought

Based on a Teagasc press release from August 2021

Six-species swards outperformed perennial ryegrass monocultures and were considerably more resistant to drought. New research from Teagasc, Johnstown Castle and Trinity College Dublin shows that multi-species mixtures receiving 150 kg/ha/year of nitrogen fertiliser, out-yielded perennial ryegrass monocultures receiving double that amount of fertiliser (300 kg/ha/year). Increases in plant diversity up to six species in intensively managed grasslands reduced the impact of drought, and produced more yield with less fertiliser.

6-species swards from dairy grazing system at Teagasc, Johnstown Castle. 

Multi-species mixtures: our publications

I regularly get asked for references to our work on multi-species mixtures. Here’s an overview of the research that we have published over the last 15 years or so.

Our research at European Grassland Federation 2013

The Role of Grasslands in a Green Future

Proceedings of the 17th Symposium of the European Grassland Federation (Eds. Áslaug Helgadóttir, Alan Hopkins)

Akureyri, Iceland, 23-26 June 2013

This was another excellent EGF conference at a wonderful location in Akureyri, Iceland. The scientific programme was as impressive as the social programme, which featured waterfalls, geysers, choirs, horse exhibitions, and 'cured shark'. Cured shark is certainly an acquired taste, and was considered by one participant as tasting like 'a baby's nappy' (or what they imagined a baby's nappy would taste like...).

Here, I provide the titles, abstracts and contact details of the four contributions that we made to EGF2013. Of particular interest was the growing frequency of research into multi-species mixutres of grasses and legumes. The opening talk by my good friend and long-time collaborator Andi Lüscher was a tour de force of this theme, and his paper will be published in Grass and Forage Science in due course. I also provide the abstract of his talk.