Sea2Soil sets market-leading results in grassland trials testing a range of biologicals
Terrafarmer-run farm trials, funded through an Innovate UK research project, are testing and comparing a range of different biological stimulants applied to grassland. Results so far have shown their potential to reduce inputs and improve grass quality.
How has Sea2Soil performed?
Sea2Soil fish hydrolysate delivers a wide range of plant-available amino acids, macronutrients and trace elements to both the crop and soil. Sea2Soil performed very highly in all trial measurements taken, including giving increases in kilograms of dry matter (DM)/ha, crude protein, trace element availability, and microbial biomass, when compared with a control treatment.
According to regenerative agronomist and soil consultant Will Marris at Terrafarmer, a number of products tested (including Sea2Soil) are improving crude proteins and sugar. “If that goes into a silage clamp, you’ve got more sugars for the fermentation process. If you get a better fermentation, you get better-quality forage.”
Out of 7 biological product treatments tested in the trials (over 7 different farm sites), Sea2Soil ranked No.1 and performed highest for crude protein improvement (at 136.225 g/kg) compared to all other products and the control treatment. Sea2Soil also ranked No.3 out of all treatments for improving microbial biomass in mid-season assessments taken. Each farm trial site used large 20 x 160m strips to test all treatments and baseline analysis measurements were taken for all products tested for comparative purposes.
Sea2Soil fish hydrolysate, as a naturally high source of protein and carbohydrate, is a perfect choice for improving soil biology. “By feeding the beneficial underground livestock in the soil i.e. the bacteria and fungi, these in turn are helping with the mobilisation of vital trace minerals such as boron, manganese, and magnesium,” says Grant James, Business Development Manager, Sea2Soil.
Soil, leaf, and forage tests from the trials show more of those nutrients being readily plant-available moving from the soil into the leaf, and therefore into the forage. “This could even reduce the need to supplement trace minerals given to livestock through licks or drenches,” suggests Will.
How biologicals like Sea2Soil work to benefit plants
Traditional fertilisers such as urea or ammonium nitrate prills have an efficiency rate of about 50%. By contrast, solubilised and foliar-applied alternatives can be almost twice as efficient, so less nitrogen is needed. “If foliar nitrogen is applied with biologicals such as molasses, fish hydrolysate, and fulvic acid, nitrogen use efficiency is improved, as you’re applying plant-available nitrogen to the leaf, which is a more direct route into the plant. That’s safer for the plant, but also beneficial and safer for the soil,” explains Will. “You’re feeding the plant and the soil at the same time, and the nitrogen doesn’t get lost via volatilisation or tied up in the carbon and nitrogen cycles in the soil.”
By applying biological and soluble fertilisers like Sea2Soil, farmers can build soil function and fertility, carbon and organic matter, all generally at reduced cost. “Biologicals are inherently more sustainable than a manufactured synthetic nitrogen source,” continues Will. “We’re not saying don’t use any, just try to use a bit less and make it more efficient.”
Valuable cost savings being realised
Using biological and foliar fertilisers can also bring significant cost savings. For example, a grass-based, multicut system might use 250kg/ha of nitrogen. Based on a standard urea application, using a 46% urea product, at a cost of 46p/kg, the cost would be £115/ha. Will explains: “Where we have added in two biological products, molasses and fish hydrolysate (Sea2Soil), to the foliar nitrogen mix, we had a saving of £5/ha,” he says. “A total cost of £110/ha to get a more efficient form of nitrogen into the plant, while reducing nitrogen use by 20%, is quite significant – and you’re feeding the soil.” He adds that nitrogen application rates can, over time, be reduced even further.
“You could easily reduce inputs starting at 25% to 50%, but that wants to be done over a few years in a managed reduction,” he advises. In addition, there is the potential for farmers to save on inputs such as mineral supplements because of the improved flow of nutrients from soil to forage with Sea2Soil and other biologicals.
Timing of application is important
The time of day and weather conditions can make a significant difference to the effectiveness of biologicals and foliar nitrogen, Will says: “If you’re looking at foliar nitrogen plus biologicals, it’s important to time your application right. Early in the morning is a good time, because that’s when the stomata are open.”
He adds that in the morning, especially, the plant will not be overly stressed, so is better at taking in the product, leading to greater efficiencies. While temperature is an important consideration, UV index and humidity should be considered first when applying biological fertilisers and foliar applications.
“When you have a high UV index, the plant is conserving moisture, and it’s not going to want to take in any nutrition,” says Will. “So the biological fertiliser or soluble nitrogen will sit on the leaf and can scorch or burn it, particularly if you’ve got urea in there. It’s best to apply these when the UV index is low and humidity is high. Humidity means moisture, and that means stomata are open to take in these products.”
Sea2Soil recommends applying the product to grassland in 2 or 3 split applications in early spring, mid-spring and late-spring or early summer, and it is also worth taking into consideration grazing cycles as well, so product application is timed around those periods, as Grant explains: “For grassland and herbal leys, applying Sea2Soil at 10 L/ha just before the start of the active spring growth period sets a good baseline and then follow-up with at least one repeat application in May.”
Multiple Sea2Soil foliar applications of 5-10 L/ha can be made in the season up to 3-6 times a year, and Terrafarmer trials work is showing that a ‘little but often’ approach to applications can work well in many grassland situations.
For more information about trials work with Sea2Soil or about using the product this season, please contact Grant James directly.
T: 07976 879646
Acknowledgments: Sea2Soil would like to acknowledge Terrafarmer Innovate-UK trials work and
FW / FWi 04 Nov 2025 article ‘Biological Stimulants: Are they good for grassland?’, read the full article here.