Kelp extract can help promote healthy soil biology and crop resilience

The project, ‘Assessing Sugar Kelp Extracts as a Nutrient Management Tool’ (or SKE-NMT), is in its early stages and is led by Algapelago Marine Ltd in collaboration with project partners The James Hutton Institute, Atlantic Mariculture Ltd and the UK Agri-Tech Centre.

This project responds to the need for more efficient nutrient management in agriculture by adopting a biological approach, valuing the importance of microbial and fungal communities in the breakdown, cycling and retention of nutrients in soil.

Through application of seaweed biostimulants under reduced mineral fertiliser application, this project aims to confirm new nutrient management options through stimulating plant responses and promoting healthy soil biology.

Seaweed supplements (due to their uniquely rich profile of fibres, micronutrients and bioactive components) enhance the growth of specific microbiota in soil, which leads to a cascade of biological functions with beneficial impacts for productivity, resistance to abiotic stress and resistance to pathogens.

This approach is relevant across a wide range of crop types including broadacre, horticulture and top fruit.

As such, use of seaweed biostimulants meet multiple biotic and abiotic challenges to transition to more sustainable and resilient farming systems.

This will unlock further research opportunities to explore larger-scale field trials to confirm the ability of kelp biostimulants to improve Nutrient Use Efficiency (NUE).

How does it work?

Rhizosphere microbiota is a collection of microorganisms that live in the soil and around plant roots and plays an essential role in the degradation of organic matter, nutrient retention and recycling.

Previous work has shown seaweed extract application improves microbial diversity and community structure and benefits crop yield and quality.

The SKE-NMT project builds on an ongoing Innovate UK project, called ‘Optimising Low Energy Extraction of Kelp for Soil and Livestock Nutrition’, and is assessing the ability of biostimulants and livestock feed additives, again derived from sugar kelp using a novel low energy extraction method, to influence feed efficiency and improve soil health.

The seaweed extracts are novel, firstly because cultivated sugar kelp (a type of brown alga native to UK coastal waters) is a new species in the seaweed extract industry with a unique biochemical profile.

Secondly, these extracts are produced using a novel low-energy fermentation and extraction process.

Cultivated kelp offers a sustainable and scalable alternative to wild harvested marine biomass. However, the potential of novel cultivated seaweed biomass, particularly in applications like biostimulants, remains underexplored.

This project aims to establish an innovative supply chain where cultivated seaweed biomass serves as a cornerstone, significantly contributing to the global transition toward sustainable agricultural practices.

The new SKE-NMT project will quantify the ability of these low energy seaweed extracts to improve nutrient use efficiency in stringently designed crop trials.

This will explore yield responses under reduced nitrate and phosphate conditions and correlate improved uptake of Nitrogen and Phosphorus under fertiliser limitation with impacts on microbial diversity and community structure.

The project will combine the development of new technologies (novel seaweed extracts) with further means to improve nutrient use efficiency in arable and horticultural systems.

Wider impacts

Conventional nutrient management systems depend on high mineral fertiliser inputs, leading to high input costs and environmental issues.

Incorporation of seaweed supplements can improve NUE with significant implications for carbon emissions and soil fertility.

This project tests the hypothesis that cultivated sugar kelp extracts can improve NUE in a UK setting.

Farmers are facing significant social and political pressure to maintain productivity while reducing leaching of nitrate and phosphates into watercourses, improve soil fertility and decrease emissions from nutrient management schemes by reducing mineral fertiliser inputs.

Luke Ansell, head of operations at Algapelago Marine Ltd, said: “We’re thrilled to have secured funding for a second Innovate UK project focused on the development of kelp biostimulants.

“The project aims to address data gaps and build the evidence case for the role of cultivated seaweed extracts in modern crop production.

“The SKE-NMT will test the hypothesis that sugar kelp extracts can improve plant nutrient use efficiency here in the UK.”

Dr Adrian Macleod, Innovation Manager at Atlantic Mariculture Ltd, said: “We are delighted to have been provided this opportunity by Innovate UK.

“Seaweed aquaculture is a game-changer for sustainable food systems, and I’m passionate about unlocking its full potential.

“Cultivated seaweed biomass offers a scalable, sustainable solution that not only supports marine ecosystems but could also play a vital role in sustainable agriculture.

“This project is an exciting step forward in demonstrating how seaweed biostimulants can enhance soil health, improve nutrient efficiency and reduce reliance on conventional fertilisers.

“By developing an innovative supply chain, we are laying the groundwork for a future where cultivated seaweed is a cornerstone of both aquaculture and agriculture.”

Gordon McDougall, research leader at the James Hutton Institute, said: “We are delighted to bring our expertise in seaweed biochemistry, biostimulants and crop trials to this important research project.

“Understanding how these novel low energy seaweed extracts can reduce inputs of nitrogen and phosphate fertilisers, maintain or improve crop yield whilst altering the soil microbiota could provide new approaches for greener agriculture.”

Martin Sutcliffe, innovation lead for aquaculture at the UK Agri-Tech Centre, said: “The UK seaweed farming sector has great potential to meet the needs of other sectors such as arable farming.

“Projects like this can provide real world use cases for seaweed farmers, enabling sustainable growth of seaweed farming in the UK which, in turn, can provide well-paid, long-term jobs in our coastal communities, helping to shift away from the current boom and bust cycle of seasonal employment.

“I’m really excited to see the results of this work and how, together with similar projects the UK Agri-Tech Centre is working on, we can move towards a more resilient, sustainable food system in the UK.”