Roger and Hillary Bell run a highly efficient grass-based beef and sheep unit on 78ha, at Kells, Co Antrim.

The upland unit carries 500 breeding ewes lambing through March and April. While the flock is made up of multiple breeds, the most common cross is a Texel Mule ewe.

All aspects of lamb performance are measured from birth through to slaughter, with the flock run through an EID handling unit every two weeks to capture weight gains.

Lambs are finished off grass on a rotational grazing system with some strip grazing in place. Around 90% of lambs are sold by autumn before the rams go out to join ewes for mating.

The cattle herd extends to 70 stores, split evenly between suckled calves purchased every autumn and dairy-bred beef animals.

Cattle are normally wintered, grazed once and finished out of the shed during their second winter housing period.

Move to net zero

Last week, Roger and Hillary hosted a farm walk outlining their plans, which will hopefully take their farm towards net zero emissions as part of the ARCZero (Accelerating Ruminant Carbon Zero) project operating in Northern Ireland.

There are seven farms in the project, split between beef, sheep and dairying, with funding coming through a number of industry partnerships.

The central theme is measuring the amount of emissions produced by livestock on each demo farm, as well as the amount of carbon being sequestered through pasture, hedges, trees, etc.

In 2021, a baseline audit was carried for each farm with data fed into the AgReCalc system developed by the Scottish Rural College.

A follow-up audit will be completed at the end of the project in 2023, although the changes being implemented on farm will take several years to deliver significant moves towards net zero carbon.

That said, there are quick wins to be had on all farms by changing the approach to slurry and chemical fertiliser use, multispecies swards and improving livestock performance from grass.

Starting point

The initial carbon audit indicates that the farm is offsetting 55% of net greenhouse gas (GHG) emissions from all farming activities, mainly through the sequestering of carbon in grassland soils.

The net figure is vital for agriculture, as opponents to livestock farming continually refer to gross emissions from animals.

As gross emissions ignore the carbon being captured on farm, it is a heavily distorted figure and an unfair representation of the sustainability of Irish farms.

Hedgerows account for 10ha of land and are allowed to grow out to maturity rather than cutting back every year.

For Roger, starting off at 55% net carbon was a positive outcome from the audit.

“We have been working hard at out grassland management, but we wouldn’t have been doing anything out of the ordinary in terms of sustainability.

“So starting off at 55% was a big positive in our eyes as we are an intensive unit and if we can make gains, every farm can make the same gains.

“The outcome of the audit shows that farmers have to nothing to fear around measuring carbon.

“We are just starting to make changes to increase the amount of carbon sequestered and lower our farming emissions.

“There is no silver bullet to get to net zero. It will take time and it will be challenging.

“But we are already seeing some of these changes having a positive impact on our farm, with multispecies swards reducing fertiliser use,” outlined Roger.

Harnessing advice

As well as participating in the ARCZero project, Roger and Hillary are no strangers to hosting farm walks, having a long history of working closely with farm advisers and research programmes.

They participate in the NI GrassCheck programme by measuring grass weekly. They are also a technology demonstration farm in partnership with CAFRE, giving advice to farmers on improving grassland management.

Breaking down the source of farm emissions

During the farm walk, there was an overview of where the mains sources of greenhouse gases (GHGs) are on farm.

Overall, the farm produces 21.99kg of CO2 equivalent for every 1kg of deadweight produced by livestock.

This is 28% lower than the 30.7kg produced by the average farm measured through the AgReCalc programme, which has data from over 1,200 farms across the UK, many of which are large-scale units with low stocking rates.

Fertiliser is the biggest source of emissions on farm, accounting for 39%. Livestock is the second highest at 36%, then manure management at 15%.

The farm is part of the ARCZero project in Northern Ireland, which aims to get farmers moving towards net zero carbon.

After this, fuel accounts for 3%, purchased feed is 2% and the remaining 2% is grouped as miscellaneous.

While fertiliser is the highest source of emissions, the figure does not tell the full story and is one of the major problems farmers face when it comes to getting to net zero.

The Bells grow second-cut silage, all of which is sold as a cash crop every year.

It provides a valuable income for the farm and one Roger does not want to give up.

Downside

“The downside of this is that we have to carry all the emissions from producing this crop of silage, such as fertiliser and fuel.

“The forage is sold off farm. But our customers who buy this feed do not have to carry any of the associated emissions with growing the grass.

“This means if we didn’t grow our own feed, and bought it all in, our net carbon footprint would increase significantly, as we would have lower emissions despite using the same amount of feed,” said Roger.

1 Multispecies swards and fertiliser

Changes to the way the farm operates are gradually being implemented, with the main one being the introduction of multispecies swards (MSS).

Six acres of MSS were sown out in 2020 using plantain, chicory, white clover and ryegrass, with a similar area planted in 2021 that incorporated some red clover.

MSS were established with a stale seed bed, ie ploughing and leaving for weeds to develop, before burning off and sowing out the new grass mix after the weeds die back.

So far, the swards are working well and helping to finish lambs without any concentrate. Fertiliser applications have also reduced, with just one bag/acre of urea applied in early spring.

By scaling up the MSS across the farm, there is potential to reduce fertiliser use, with some early estimates pointing to a 65% drop in chemical nitrogen use.

Savings

At current prices, this would save as much as £15,000 (€ 17,647) annually, provided swards can maintain 35% clover content. GHG emissions would subsequently be reduced by 9%.

MSS are also improving the natural drainage of land, reducing nutrient run-off in wet conditions.

Soils were mapped using Lidar technology and fertiliser and slurry are no longer applied to fields where there is a risk of run-off.

Future plans will also see the use of low-emission slurry spreading (LESS) equipment to reduce ammonia emissions and increase nutrient availability for grass growth.

2 Hedgerow and soil management

Planting more trees and hedges has been heavily promoted as the answer to climate change, but while they do sequester carbon, it is very much a long-term project.

Instead, speakers outlined how farmers can benefit by changing the way hedgerows are managed.

Advice was to move away from cutting back hedges every year, as most farmers tend to overcut leaving small open hedgerows that offer little benefit in terms of promoting wildlife or sequestering carbon.

Instead, the advice was to trim hedges on a rotation every few years. This allows hedges to grow out and upwards, increasing the canopy size for capturing carbon.

Soil structure below these mature hedges will also improve, with soil porosity increasing by 60% along field boundaries, again reducing nutrient run-off.

On Roger and Hillary’s farm, over one mile of hedgerows has been constructed in recent years. Hedges now cover an area of 10.2ha on farm, plus 1.48ha of woodlands which, when combined, are holding 188.4t of carbon.

Soils also store 13,885t of carbon. Soil sampling on the farm shows that as soil organic matter increased, so did the level of carbon sequestration. Soils with the highest carbon stores had more than 30% organic matter, had a high clay content, were laid out in permanent grassland, and used for grazing only, with slurry and farmyard manure applied regularly.

Overall, the amount of carbon stored on farm is 14,073t of 51,507t of CO2 equivalent.

3 Efficient livestock production

While the MSS and hedgerow management are important, at the core of the farm are the livestock enterprises which generate income.

Sheep are rotationally grazed and sward quality is excellent. Despite farming in an upland area, grass growth in 2021 exceeded 12t DM/ha, which is almost double the NI average.

Multispecies swards are now grown to reduce fertiliser use.

Liveweight gain in lambs is measured every two weeks, with weekly checks carried out as lambs come close to slaughter weight.

The 500-ewe flock has a target lambing percentage of 200% and achieves 207% to 220% most years, with mortality levels at 3%.

A high lambing percentage does mean there are more pet lambs to rear annually, but this is something the Bells are happy to contend with.

Roger said: “Our emissions are measured on every breeding ewe, so we want all ewes rearing two lambs at grass. We cross-foster as necessary and rear the surplus lambs on a feeder.

“We want two lambs reared per ewe as this reduces the emissions generated on farm over more kilos of deadweight produced.

“Having dry ewes is costing us from a carbon viewpoint, so we only want productive sheep.

“Replacements join the flock as ewe lambs rather than hoggets as it is the most efficient option for us.”

Lamb carcase weight averaged 20.7kg in 2021, with animals drafted for slaughter at an average 46kg liveweight.

When measured against the other UK farms using the AgReCalc system, the Bells are finishing lambs 42 to 43 days earlier than the average farm, all from a grass-only diet.

This means that the sheep enterprise on the Bells’ farm is producing 41% more output than the average farm with 28% fewer emissions.

While the sheep flock is already extremely efficient, Roger maintains there are potential gains to be made as the area of MSS increases as well as harnessing the best genetics in the flock.

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