Nitrogen fixing clover can lessen fertiliser dependency

Tuesday 15.02.2022 , News

The high cost of inputs coupled with a much-increased focus on environmental factors are both influencing reseeding decisions this spring. Including nitrogen fixing clover in your grass seed mixtures and reducing fertiliser use in the longer term are part of the solution.

Nitrogen fixing clover

Research suggests up to 150 kg N/ha can be made available through nitrogen fixation, reducing the need for artificial nitrogen applications. As such, clover seed varieties can be a cost-saving ally and ideal for sustainable farming.

Legumes, such as red and white clover, fix nitrogen thanks to a partnership between their root nodules and soil-dwelling Rhizobium bacteria. The bacteria take nitrogen as ammonia from the air and convert it into a form available to companion grasses. So, including clover in a grass sward offers the greatest benefit to your grassland.

The easiest way to establish clover in a sward is as part of a full reseed using a clover and grass seed mix. For silage swards, a mix of perennial ryegrass and red clover is recommended, with perennial ryegrass and white clover more suited to grazing swards.

Nitrogen fixation improves with clover

If you achieve an average clover content of 25-30% in a sward across the year, nitrogen applications can drop to 150 kg N/ha and still produce the same amount of herbage as a grass-only sward receiving 250 kg N/ha. This provides significant cost savings and a major environmental benefit.

The reduction in applied nitrogen is also important for gaining the most from clover’s ability to fix nitrogen in soil. If more artificial nitrogen is spread, less nitrogen is fixed by the clover.

In addition to fixing nitrogen in grassland, research also shows swards containing at least 20% white clover improve animal production, due to its high quality and digestibility driving higher intakes.

“The current high fertiliser prices are really focusing the mind on making a success of clover. Where we’ve been sowing clover for the last few years, we’ve cut back on our nitrogen applications and the clover has grown well, increasing its percentage within the sward.”

Brian Hogan, Co. Tipperary

With significantly elevated fertiliser prices, it is an ideal opportunity to consider cutting back on the level of bagged nitrogen applied to fields with a reasonable amount of clover already present.

Together with building more nitrogen fixing clover into your grassland management and reseeding plans this season, you’ll be well-positioned to capture the positive economic and environmental benefits now and into the future.

Ask the clover experts

For advice on sowing nitrogen fixing clover, ask our grass and forage production experts.