Lambs are being drafted 10-14 days earlier on grass/clover swards compared to grass-only swards at the Teagasc Centre in Athenry, Co. Galway, Philip Creighton has said.
The grassland research officer based in Athenry spoke about the benefits of including white clover in seed mixes, how it can be incorporated into swards, and the benefit it has on lamb performance.
Philip explained: “There are three main benefits to incorporating clover into swards. The first one is the effect it has on lamb performance.
“Particularly after weaning, lamb performance increases on grass/clover swards compared to grass-only swards.
“What we are seeing here in Athenry is the lambs are being drafted 10-14 days earlier on the grass/clover swards compared to the grass-only swards.
“In terms of fertiliser, specifically nitrogen use, we are able to reduce the amount of chemical nitrogen (N) we are putting into the system to support the same level of output.
“Trials going on here are seeing grass/clover swards that are receiving 90kg of chemical N per hectare over the course of the year, equalling the sward output in terms of tonnes of dry matter [DM] grown per hectare, as the grass-only swards that are receiving 145kg of chemical N.
“It’s a big saving in terms of what we have to spend on fertiliser and from an environmental point of view, it’s also a benefit as we don’t have to use obviously as much chemical N while maintaining the same level of output.”
Ways of getting white clover into the sward
Philip said that there are two main ways of incorporating clover into swards.
Expanding this point he said: “The most reliable way is through a full reseed.
“If farmers are considering reseeding, I would advise to include white clover in the seed mix and for sheep swards, we are talking about 2-2.5kg/ac or 5-6kg/ha of white clover seed to be included in the mix.
“So your typical mix will look like 10-11kg of grass – plus your 2-2.5 of white clover.
“Because sheep swards are that bit more dense, we need to include that higher seed rate to get a higher percentage of clover established in the early stages in order to compete with the grass.
“It’s important to use a small leaf clover. Small leaf clover is much more tolerant to sheep grazing. They are slightly lower-yielding but are more persistent.
“Examples include galway and aberace. They have been tested and proved to withstand sheep grazing.”
On establishing white clover in existing swards, Philip added: “You can’t reseed the whole farm at the same time, so over-sowing would be a good option there for farmers.
“Right now, May/June time is a good time to do that. We need as long a period, of good conditions, for clover to establish. We need plenty of heat in the ground for the clover to grow and establish itself.
“For oversowing, we need moist warm conditions. Temperatures look set to rise, so it would be a good time when that happens, to do that.
“The seed needs to get in contact with soil, so some sort of mechanical intervention (tine harrow or one pass harrow for example) is going to be needed for it to be a success, because no amount of heat or moisture will make it a success without the seed coming into contact with the soil.
“If you’re thinking about over-sowing, it would be best for the field in question to be grazed tight or maybe look at doing it when silage has been taken from it.”
Philip warned that if you have a weed problem in a sward, that it would be best to fix that problem first before thinking about over-sowing.
He added: “To get rid of those weeds, most of the sprays typically used have a residual effect of up to four months, which would prevent the clover from germinating, so it would be best to sort out any weed issues first this year and look to maybe over-sowing next year, while also making sure other factors such as soil fertility are all good as well.”