Major new biomass crop trial underway in Hillsborough

While biomass crops may have fallen out of fashion in many parts of the island over the past decade, this is set to change.

As we all know, the climate, biodiversity, energy and cost of living crises have put major pressure on what we do.

However, as a result, biomass crops are once again set to play an important role in the island’s energy system, as they can help address each of those challenges.

A new project at AFBI Hillsborough aims to find the most suitable energy crops to grow in Northern Ireland (NI).

The project will help fill in the missing knowledge gaps when it comes to biomass crops. It’s the first multi-site variety trial for biomass crops of this kind and scale in the UK and Ireland, representing a significant endorsement of the sector.

Researchers recently held an open day to showcase their new biomass energy crop trials, which were planted as part of a UK-wide project, Biomass Connect.

Biomass Connect

The Biomass Connect project was awarded £4.8m (€5.5m) in funding from the UK Department for Energy Security and Net Zero. The project is part of the £36m (€41.4m) Biomass Feedstock Innovation Programme.

The aim is to increase the production of sustainable UK-grown biomass through a range of multi-site demonstration platforms. The trials planted in Hillsborough are replicated in seven other sites across England, Scotland and Wales.

Biomass crops

The short rotation coppice and forestry crops planted at Hillsborough include miscanthus, willow, poplar, eucalyptus, alder and black locust. Reed canary grass, switchgrass, sida and hemp are also planted as part of the trial. The trials are assessing multiple varieties and varietal mixes.

Outcomes

The Biomass Connect project has five main goals: making people more aware of biomass through demonstrations and sharing knowledge, providing unbiased information on topics like biomass farming and its benefits, studying how well biomass crops perform in different areas, supporting innovation, and giving solid evidence for policy decisions.

Over the coming years, the crops will be assessed for their performance in NI conditions, with a range of information resources for growers set to be produced. It is envisaged that the outcomes from the project will be key to achieving significant UK targets set out in a recent Biomass Strategy.

The strategy has set a target to plant an additional 9,600ha of perennial energy crops and 8,900ha of woodland annually by 2030. This will increase to 15,000ha of energy crops and 10,300ha of new woodland a year by 2035.

Biomass at AFBI

Chris Johnston, AFBI, told attendees of the open day that the organisation is involved in multiple research projects involving biomass, from pollution management and bio-filtration solutions to yield and phyto-bioactives trials.

The Catchment Care project, for example, which used willow as a buffer along watercourses, was finding encouraging results, like a 35% reduction in phosphorus runoff from fields.

AFBI Hillsborough itself, as well as having an onsite anaerobic digestion plant and solar PV, also has a biomass boiler that provides heat to the site.

Callum Williams, AFBI, then took the group for a walk around the trial site to see what was planted, and updated us on the progress of the crops. The crops were planted this year, from March to June.

Some of the plant stock came from GB, and the new customs and phytosanitary rules did cause delivery delays for some of the stock.

Miscanthus: A C4 rhizomatous, perennial monoecious grass that produces woody stems. Two types of Miscanthus were planted: giganteus and a newer variety, Athena.

The rhizome cuttings were planted at 20,000 plants/ha, at a spacing of 1m x 0.5m. Weed control was a challenge in places around the site, particularly chickweed and thistles, and required herbicide control.

Miscanthus needs a lot of water to produce a good crop, potentially making it attractive for NI. The market for the crop in England is booming, as attendees heard.

Willow: One of the most popular short-rotation coppicing species for energy crop production. A six-way willow variety mix consisting of rust-resistant varieties was planted.

The 20cm cuttings were planted at a rate of 16,667 plants/ha in twin rows of 1.5m and 0.75m, with 0.59m in the rows.

Willow can be harvested on two to five–year rotations at densities of up to 15,000 plant/ha, depending on the productivity of the site and the environmental conditions.

Hemp: The hemp varieties were chosen based on three markets, with each variety sown for that market.

These include varieties for fibre, where the stems were taller; for seed, where the plants were short with larger heads; and dual-purpose, where varieties were grown for both markets. The plants were sown at 200 seeds/m2, 150 seeds/m2, and 100 seeds/m2 respectively.

Alder: Common alder is a water-loving tree that grows well in swampy areas or close to rivers, lakes and ponds, with root structures that provide support towards the prevention of soil erosion in these areas.

The wood produced from this species isn’t as susceptible to rotting when waterlogged. The plants were planted at 5,000 plants/ha and 1,667 plants/ha in another trial at a spacing of 2.0m x 1.0m.

Eucalyptus: Eucalyptus is a flowering tree species, known for its strong aromas and rich oils, which make it highly flammable.

Irish plantations of Eucalyptus have been impacted by the psyllid pest Ctenarytaina eucalypti and the leaf beetle Paropsisterna selmani, which could require consideration.

The crop was planted at a rate of 2,500 plants/m2 at a spacing of 2.0m x 2.0m.

Poplar: Poplar is among the fastest-growing of temperate trees, and is therefore of considerable interest as a bioenergy crop. The plant grows to a height of 15 to 50m, with a trunk diameter of 2.5m. Once established, poplar can be harvested every two to five years over a lifespan of over 20 years. The crop was planted at a rate of 1,667 plants/m2 at a spacing of 3.0m x 2.0m.

Reed canary grass: Reed canary grass is a multipurpose, lignocellulosic perennial crop. It is a fast-growing crop reaching heights of 1.5 to 2m in a growing season and, depending on management, can remain productive for five to 10 years. Average yields of five to seven tonnes/ha are achievable in the UK. The crop was planted at a rate of 25 to 10kg/ha, at a spacing of 12.5cm.

Switchgrass: Switchgrasses are C4 perennial monoecious grasses native to North America. The crop was planted at a rate of seven to nine kg/ha.

Sida: Sida hermaphrodita is a perennial herbaceous forb species native to the eastern part of the United States. It is neither a grass nor a short-rotation woody crop; instead, it can be defined as a soft, woody herbaceous energy crop. The crop was planted at a rate of 40,816 plants/m2 at a spacing of 0.7m x 0.35m.

Black locust: This is a medium-sized hardwood deciduous, nitrogen-fixing tree. Black locust is a fast-growing tree, often growing to a height of between 12 to 30m high.

However, black locust can be considered an invasive species. The crop was planted at a rate of 3,333 plants/m2 and 6,666 plants/m2 in another trial at a spacing of 2.0m x 2.0m.

For more information, go to www.biomassconnect.org

Miscanthus wanted

Miscanthus certainly has had its challenges on the island, but a new market is emerging, which may create opportunities for farmers.

Michael McEvoy of BedMac, a horse bedding manufacturer in Banbridge, Northern Ireland, processed miscanthus as part of a bedding trial carried out in CAFRE’s Enniskillen Campus.

The results were very positive and last year, Michael started to sell miscanthus for bedding with good feedback from customers.

With oilseed rape straw becoming increasingly hard to source, Michael sees a bright future for miscanthus bedding, and he is now on the lookout for growers interested in supplying the crop – either from an existing plantation or from a new one – to his bedding company. For more information, visit BedMac’s website.