Multispecies grasslands produce more yield from lower nitrogen inputs across a climatic gradient

Area of Science:

• Agricultural Science
• Ecology
• Agronomy

Background:

• High-yielding grasslands often lack species diversity and rely on high nitrogen (N) fertilizer inputs.
• Conventional practices include grass monocultures or simple grass-legume mixtures.

Purpose of the Study:

• To evaluate multispecies forage mixtures as a sustainable alternative to conventional grassland management.
• To assess the impact of species diversity on grassland yield under varying nitrogen inputs.

Main Methods:

• The international LegacyNet experiment involved 26 sites, testing grasslands with up to six species (grasses, legumes, herbs).
• Management involved moderate nitrogen inputs, comparing diverse mixtures against grass monocultures (higher N) and grass-legume communities.

Main Results:

• Multispecies mixtures significantly outyielded both grass monocultures and two-species grass-legume communities.
• High yields in diverse mixtures were attributed to positive interactions between grasses-legumes and legumes-herbs.
• The yield benefit of legume-containing mixtures increased in warmer climates.

Conclusions:

• Optimizing grassland mixture design can lead to more sustainable forage production.
• Diverse grassland systems show potential for adapting productive grasslands to a warming climate.