A recent webinar hosted by AgriSearch has confirmed the role for red clover in improving the quality of grass silages.

The event was hosted under the auspices of the ongoing ZeroNSile project in Northern Ireland.

Courtesy of his opening comments, AgriSearch general manager, Jason Rankin, highlighted the key role that high quality silages play within all ruminant production systems.

He added that recent years have seen increased costs and greater volatility where the price of chemical fertilisers is concerned.

“Fertiliser use accounts for approximately 20% of greenhouse gas (GHG) production on farms across Northern Ireland,” Rankin said.

“Significantly, trials carried out by Agri-Food and Biosciences’ Institute (AFBI) scientists have confirmed that red-clover-based swards can deliver high yields, and equally high levels of protein without the use of chemical nitrogen (N).

“However, there has been a low uptake of this production option up to now,” he added.

The ZeroNSile project has seen red clover swards established on 11 farms over the last 12 months.

According to Rankin, 2024 will be the first year in which intensive monitoring of the swards will take place, and “a smaller scale lucerne project has also been established on three farms in Co. Down”.

Red clover

According to the AgriSearch representative, red clover varieties have the potential to fix 200kg/ha of nitrogen (N) from the atmosphere on an annual basis.

Trial work carried out by AFBI has confirmed that pure strands of of this variety can produce up to 13t of dry matter (DM)/ha/annum.

“As a consequence, farmers growing silage swards containing significant quantities of red clover need only add the required levels of potash and phosphate to ensure that high levels of productivity are secured,” Rankin continued.

“In addition, the protein in red clover is of an exceptionally high quality. This then allows livestock farmers to reduce the levels of additional protein they offer stock in concentrate feeds.”

However, Rankin is also acknowledging that this particular type of clover is a complicated crop to grow.

“Soil pH, phosphate and potash levels must be correct in order to optimise crop growth,” he explained.

Red clover grows from a single point within the plant. If this crown is damaged, issues relating to persistency within a silage sward will arise,” he explained.

“As a general rule of thumb, it is now envisaged that red clover will persist within silage swards for a maximum of four years.

“It is generally recommended that a mix of red clover, white clover and perennial ryegrass should form the main constituents of a 10-year silage sward.”

The AgriSearch manager said that red clover will generate its impact during the first four years, post-establishment.

Thereafter, the ryegrass and white clover can maintain the high levels of output and forage quality until such times as the ground is reseeded again.