Why all grass isn’t equal

Ryegrass has dominated UK grassland in recent years. It’s reliability as a source of good-quality, high yielding forage has meant it is an easy choice for livestock farmers.

However, drought and the need for high inputs of fertiliser have combined to make ryegrass a less viable option and many farmers are seeking alternatives.

Research carried out through a collaboration involving the University of Reading, Duchy College, Rothamstead Research North Wyke and Cotswold Seeds has been investigating the potential of alternative forage crops, both from a feed value and an environmental point of view.

Results from two previous studies were used as the starting point for the five year research project: one showing the nitrogen-saving benefits and drought tolerance where multi-species mixtures were used; the other was the health benefits to sheep when fed multi-species forage.

An earlier Defra study was also referenced. This had shown reduced methane production in heifers when fed a diverse forage mix as haylage.

This most recent research looked at four groups: three multi-species mixes and one perennial ryegrass. The ryegrass received nitrogen, while the multi-species received no nitrogen at all.

The method and results of the study can be accessed here but the headline findings were: biomass yields were similar across all groups in year one and two but the multi-species showed greater yields in year three. There was little difference in the four test conditions for live weight gain. Methane production was reduced on the multi-species plots and the nitrogen fixing properties of the legumes in the multi-species plots were beneficial for reducing future fertiliser requirements.

The results suggest there are benefits to using multi-species swards but there are also some negatives that farmers should consider before making a switch. In particular, the performance of multi-species swards can vary across locations and landscapes and the best ways of managing complex mixtures are still to be understood fully.

Picture courtesy of: Tim Woodson on Unsplash