Overseeding keeps grassland in production and more productive

Opting to overseed some pastures, rather than carry out a full reseed could be the answer for livestock farmers wanting to minimise costs but not lose out on the production of the cheap energy source that is grass. Nigel Barnes of Powys Leys has been advising farmers on boosting sward production, and Montgomeryshire grassland contractor Mike Holloway has been overseeding fields in just one pass with a new machine – a Sward Rejuvenator.

The productivity of grassland has a direct correlation with the profitability of livestock farms. “So despite current financial pressures, farmers should not be letting their leys fall into disrepair, says Mr Barnes.

“Carrying out a full reseed costs around £450-550/ha [£180-220/acre], but overseeding can be done for a third of this cost. Plus it doesn’t require fields to be taken out of production, they can continue to be grazed or silaged whilst new young plants establish.”

Tips and tactics

However, to help ensure a successful overseed of worn pasture, certain tactics are required.

Mr Barnes and Mr Holloway recommend overseeding is carried out straight after a cut of silage has been taken, or when sheep have grazed the sward down tight.

Following a recommendation made on a visit to a grassland open day last year, Mr Holloway has adopted the practice of including a low dose of slug pellets into the seed hopper.

“I add just enough to protect the seed while it gets established,” he explains: “Last autumn I overseeded some grassland on my own farm. A week later, there’d been no rain, but I couldn’t find any pellets. So the slugs must have had them!”

Mr Barnes adds: “Overseeding can be done quite late in the year because the existing grass gives the seedlings some protection from frosts. It also aids moisture retention, which is especially valuable in the summer months.

“Overseeding is also a good way of getting clover back into leys. But with only ‘clover-kind’ herbicides available, it’s best get leys weed-free before seeding.”

Previously, Mr Holloway used to use a direct drill for overseeding, making two passes at right angles and then rolling. But he has recently added a new piece of machinery to his grassland kit, an OPICO mounted Sward Rejuvenator, primarily designed for overseeding, but also capable of aeration and seeding into cultivated land.

Mr Holloway explains:  “There are slicing plates at the front of the machine, followed by spring tines which make the machine more aggressive than the direct drills I’ve used to overseed with in the past. Together they open the ground up, creating some tilth and giving the seed a better chance. The heavy roller at the back of the machine also saves the farmer from having to come in afterwards and roll the field. In one pass, the job is done!”

Silage overseeding strategy

For the past four years, Mr Barnes has been working with dairy farmer Ben Beddoes with an overseeding strategy for his silage leys.

Mr Beddoes milks a 220-cow Meuse Rhine Issel herd, run on 100 acres of grassland near Churchstoke, in Powys.

Silage fields are topped up every year, straight after first cut silage, with a short term ley mixture: 20% Westerwold and 80% Italian ryegrass blend.

This is sown at 25kg/ha, two-thirds the normal seed rate, with slug pellets included in the hopper at 2.5kg/ha.

Mr Beddoes says: “We expect to take four cuts of silage. But if we ploughed the fields – not only would that be more expensive – but we’d be reduced to taking only two cuts. With the overseeding strategy the field is continuously in full production.”

Mr Barnes adds: “Last winter the field flooded, and waters brought in a lot of dock seeds. This meant selected areas needed to be sprayed off before overseeding. But in general, by keeping the pasture topped up, there are no bare patches and so no weed ingress. So, Ben has actually been using less herbicide.”

Autumn overseeding

Maintaining output from grassland by reseeding 10% each year is the strategy adopted by Shropshire farmer Matt Jones. He runs a 40-cow herd of spring-calving Belgian Blue suckler cows and a 600-ewe flock of Texel and Lleyn crosses, near Clun.

Earlier this year Mr Jones took on a tenancy and increased his grassland area from 120ha [300acres] to 161ha [400 acres]. Previously he had reseeded fields himself.  But now farming more land and having taken on the rearing of 450 ewe lambs, he is employing the services of his local contractor. This will work out as a more cost-effective use of his time.

The autumn is the preferred time to reseed. There is less livestock work and there needs to be plenty of grass ready for spring grazing.

Mr Barnes adds: “Last autumn Matt had an 8 acre field with an old ryegrass ley. He needed to increase its production and also wanted to make high quality silage. So I recommended oversowing a mixture of hybrid and perennial ryegrasses together with red and white clovers. He’ll be able to take 2-3 cuts of silage, and can utilise the red clover for finishing lambs on in early autumn.”

So instead of the usual reseed operation, the ley was oversown in early September last year, straight after a late silage cut had been taken. Mr Holloway used a trailed version of the Sward Rejuvenator - on loan –and again a seed rate of 25kg/ha and slug pellet rate of 2.5kg/ha.

Mr Jones explains: “The old ryegrass ley was at the end of its life, the sward had become very open at the bottom. Three weeks after overseeding, I was grazing my sheep on it. So it was much quicker than a reseed, and I didn’t lose any production from it. When I shut it off for silage mid-May this year, it was looking like a new ley.”

Mr Barnes adds: “Overseeding will never replace a plough and full reseed. But by keeping pastures topped up, then for around £130/ha [£50/acre], there’s an extra 3-4t of DM of silage to be made each year. It’s a no-brainer.”