Seaweed: Land and sea
A community-owned sea farming venture in Pembrokeshire, Wales, has found that its crop can be used to help farmers on land, too.
St David’s-based community business Câr-y-Môr has licences for three farms off the coast of south-west Wales. Câr-y-Môr operates on integrated multi-trophic aquaculture (IMTA) principles, raising both shellfish – mussels – and native species of seaweed.
It’s the seaweed that was the focus of a two-year trial, with support from the Co-op Foundation’s Carbon Innovation Fund, that set out to demonstrate that locally-grown seaweed biostimulant (a naturally-derived product that stimulates plant nutrition processes) could:
- compensate for reduced fertiliser rates;
- reduce carbon emissions from farming systems;
- deliver financial benefits for farmers; and, crucially,
- maintain or increase yield, quality and soil health.
The yield and quality on trialled cereal and potato fields were also maintained when fertiliser was reduced by 25% and 29% respectively.
Lead author of the study Alma Joensen said: “With increasing environmental pressures and scrutiny on nutrient management, more and more farmers are shifting their focus on to the soil and the health of life below ground. Reducing fertilisers and other chemical inputs is crucial to regenerating soil health, but often a really difficult step to take without compromising on yield and quality.
“These trial results are showing that seaweed grown just a few miles away can give farmers an immediate and practical way to increase nutrient uptake and reduce bagged nitrogen, all while maintaining output.”
Sugar kelp (Saccharina latissima), oarweed (Laminaria digitata) and furbellos (Saccorhiza polyschides, also known as furbelows) all native seaweeds, were harvested from Câr-y-Môr’s regenerative sea farms in the Ramsey Sound to make the biostimulant. Trials took place on six farms, from conventional agricultural land to organic farms, with one farmer seeing a 24% yield increase on their organic potato crops sprayed with liquid seaweed.
Agronomist Tony Little, who was part of the team conducting the trials, said: “From the start, we have worked hand in hand with farmers considering reduced nutrient programmes. Seaweed biostimulant is helping them make the most of the nutrients already in the soil, and that will compound over time.
“That’s important for the environment in terms of reducing agripollution and the carbon emissions associated with imported fertiliser production. At the same time, it helps farmers meet their obligations under the new Agripollution Regulations and can play a part in reducing the economic impact of fertiliser price volatility.”
The role of a biostimulant is related to that of fertiliser, but the two are not the same. In fact, seaweed extracts and other biostimulants have a range of effects, including increasing a crop’s resilience against drought, pests and diseases, but one key role is to improve the take-up of nutrients. Biostimulants do not replace fertiliser, but they can reduce the amount of fertiliser a farmer needs to apply to the crop, not only cutting costs but also reducing the amount of pollution generated by agriculture.
Owen Haines, voluntary Managing Director and one of the original 10 members of Câr-y-Môr, says that it is clear that seaweed grown solely as a food crop for consumers is not yet economically sustainable in the UK. The demand traditionally seen in Asia for seaweed simply is not there. It makes sense, therefore, to find other, value-adding applications for the crop.
He adds: “Here in West Wales, we’re surrounded by farming and developing the seaweed biostimulants seemed very logical.”
‘Yield is king’
Trial farmer Nicholas Evans from Crug Glas said: “Yield is king, really. We want to try and get as much off our fields as we can. If we’re cutting fertiliser, we need to know that yield won’t suffer. And that’s where we think these biostimulants come in and de-stress everything.”
Neighbouring farmer Mark Evans from Upper Harglodd added: “If we can improve the silage or the grazing, or even give long-term benefits to the soil – if we can benefit where it all starts, it’s going to set us up for a better future hopefully.”
Now with these positive trials as evidence, Câr-y-Môr is scaling production of biostimulant from its new seafood and seaweed processing facility just outside St Davids – the first dedicated seaweed biorefinery facility in Wales – in turn creating more jobs for its community, and allowing further, more extensive trials to take place.
The community business sees the seaweed biostimulant as an integral part of the regenerative system it’s creating, where land, sea, food and livelihoods are all connected.
Câr-y-Môr Director Dominic Burbridge said: “The biostimulant is produced from seaweed grown on Welsh regenerative sea farms, where kelp captures excess nutrients and shellfish filter seawater as they grow. After harvest, the seaweed strengthens soil health on land, reducing the risk of nutrient run-off at source, and some shellfish are sold for food, while others continue their ecological function to be redeployed into rivers and estuaries as natural water filters.
“This integrated approach, linking marine cultivation, sustainable food production, and freshwater restoration, is now being explored through a river restoration project with the Marine Conservation Society in the Cleddau River, demonstrating how regenerative sea farming can deliver benefits across community, nature and climate.”
The Câr-y-Môr project has around 700 members and can call on their support in a way that a private company probably could not. Even so, the route to get where it is today has not been easy.
Owen Haines says: “It’s a privilege to be part of, but it is absolutely exhausting!”
Having established a trial site, getting 20-year permits for three inshore three-hectare sites has taken two and a half years, including addressing objections raised on visual grounds by the National Trust and the Pembrokeshire Coast National Park Authority. Câr-y-Môr has committed to work closely with both of those bodies over the term of its licence.
Câr-y-Môr has generated 15 local jobs and the team has worked hard to build relationships with the local community, including fishermen.
Now, the next step will be to apply for permits for a 60-hectare farm which will be located around six kilometres offshore.
The beneficial effects of IMTA aquaculture have already been demonstrated – as the University of Plymouth’s Ropes to Reefs study of the Offshore Shellfish site off the Devon coast has shown – but even so, Câr-y-Môr will need to navigate the same permitting process that is applicable to large energy companies planning offshore wind farms.
For Owen Haines, this is about investing in future generations, and offshore is the only way to produce at scale.
He stresses, however, that inshore sites are also vital. They are many more times accessible for the nursery requirements of the multiple species being farmed, and for the training of the farming team, and testing gear and systems as farming techniques are developed. With inshore sites, it is also more practical to facilitate regular visits by the public, government and non-governmental bodies; and this, Haines says, is important in order to keep developing aquaculture’s social licence to operate.
As he puts it: “Undoubtedly the right place to go is offshore, but I think the inshore sites are critical because you need to win over the hearts and minds of people.”
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