Microbial inoculants will be part of the autumn drilling campaign on a Cambridgeshire farm this autumn, as Tom Pearson takes the next steps in reducing reliance on artificial inputs.

See also: How an award-winning arable farm combines business and nature

Tom, together with farm manager Rhys Jones and regenerative farming research and data lead Shona Russell, has made three Johnson-Su bioreactors.

And they have fitted a liquid application system with a peristaltic pump to the farm’s Horsch Avatar drill.

They are now ready to apply the home-brewed biology at a rate of 1kg/ha (diluted in 50 litres/ha of rainwater) when next year’s crop goes into the ground.

Tom Pearson © Louise Impey

The liquid extract being applied comes from compost based on plant material from the farm, which should kick-start the soil biology and support healthy crop and root growth.

The aim is to reduce the need for other interventions, become more self-sufficient through improved nutrient availability, and deliver food with better nutrition – all while working in harmony with nature.

“It will take an extra hour in the morning to have what I need for a day of drilling,” explains Rhys, who adds that the “live” inoculant needs to be applied as soon as possible and must be kept aerated.

“There is a time commitment, but the costs of creating and filling the bioreactors have been minimal,” he adds.

“We have also created two more Johnson-Su bioreactors using materials that have been growing throughout the spring, so we can make a compost more specifically primed for spring microbial communities to use for our spring 2026 drilling.”

Drilling preparations

Forward planning has been required, as it takes 300 days before a usable product is ready.

Shona takes the lead in making the fungal-rich compost, keeping it aerobic and moist before adding worms and then creating an extract using rainwater.

This is then applied with molasses and fish hydrolysate.

Shona has also planted a cover crop mix and some wheat in the top of the bioreactors, to influence microbial communities associated with the crops grown on the farm.

To this, spores from mushrooms found on the farm have been added to increase the compost’s fungal aspect.

The peristaltic pump liquid application system from Trevor Tappin was retrofitted to the drill and part funded with a Farming Equipment and Technology Fund grant.

This has provided an efficient and reliable way to apply the low-cost biology produced by the bioreactors.

Rhys Jones © Louise Impey

“Compost extracts are the obvious next stage for this regenerative business,” says Rhys.

“We have already reduced our use of fungicides and fertilisers, our fossil fuel dependence is less, and our environmental impact is minimal.

“Long-term, we want to create a more circular farm economy.”

Bringing in diversity

Diversity is encouraged wherever possible on the 400ha farm at Caxton, with agroforestry and variety blends grown, while a clover understorey has been in place in some fields for three years.

Sheep are integrated across the cereal crops as a replacement for plant growth regulators and early fungicides. Sheep also graze cover crops and the permanent clover layer. Their fertility benefit is also exploited.

As Tom explains, payments from Countryside Stewardship and the Sustainable Farming Incentive have helped to fund some of the changes made on the farm to date, and he is keen to do more when these schemes return.

The whole farm is companion cropped and direct drilled, while apple trees have been planted in flower-rich AB8 strips. Cover and catch crops feature widely, with the drill following directly behind the combine.

“Behind this is local food and system resilience,” he says. “We want to take a whole-farm approach to resilience, and tree planting is a key part of this.

“The wider area gets the benefit of more trees in the landscape delivering more biodiversity and better water management, while we have fresh produce to offer over the winter.”

Manor Farm hosts Adrienne Gordon’s Sweet Pea Market Garden, which is in its third season and featured in the documentary film Six Inches of Soil.

A separate enterprise to the farm, it has opened Tom’s eyes to the amount of food that can be produced from 1ha, and the potential of the local consumer market.

“That’s partly responsible for our agroforestry,” he says. “Currently it’s all dessert apple trees, but we hope to do a walnut and hazelnut project next.

“There are over 20,000 people on our doorstep, which is projected to be 54,000 in the next 10 years, so there’s plenty of opportunity and a great deal of interest in how food is produced.”

Low input crops

In keeping with building a resilient farming system, the farm is also growing spring wheat for Wildfarmed and has the Wakelyns YQ population wheat.

This is a mix of more than 190 crosses from 20 different wheat varieties and has been grown on the farm for the past five years.

Both are grown with companions and have significantly lower inputs, with foliar micronutrition being the biggest spend at about £20-£60/ha.

“Having a clover understorey present means we don’t have to worry about the effort and cost of cleaning and separating the crop at harvest,” Tom says.

It also reduces the weed burden and provides diversity above and below ground, although there has been some potential competition for water in this dry season, which may have an impact on yield.

These low-input crops don’t have pesticides after drilling, and weed burdens in winter cereals can cause issues, requiring a following spring crop for their management.

“We’re learning all the time about the right approach for this farm and what works best,” says Tom. “Trying out comb harrows and inter-row hoes is of interest.”

Financial considerations

Benchmarking shows that these crops often have the highest gross margins, yielding about 5t/ha and attracting significant premiums.

“We do try and graze them in early to mid-February with the sheep, before GS30, as that removes any early disease and means we don’t need plant growth regulators,” says Tom.

He stresses that it isn’t possible to just direct-drill crops and stop using fungicides.

“We’ve now got it down to using fungicides on around one fifth of the farm, but this year has been an easy season for that. Next year will be different again.”

Having said that, both Champion and Mayflower have needed some help this year, due to the new yellow rust race overcoming the genetic resistance, he acknowledges.

Nitrogen use is gradually coming down, with the final 20kg/ha supplied as a foliar urea application, made in two applications.

Dissolving urea with a carbon source and applying it to the leaf results in better uptake and has a reported nitrogen use efficiency of 65-90%, but needs spraying in humid conditions which is often at night.

Over time, the nitrogen rate has fallen from 220kg/ha to 140kg/ha soil-applied, followed by the two applications of 10kg/ha foliar urea plus micronutrient.

“There is a technique and some equipment required for dissolving urea, but it is not that complicated,” he says.

Tramline comparisons are being conducted, to try to get a better understanding of the increased efficiency and carbon footprint improvements that it offers.

Looking ahead, Tom, Rhys and Shona hope to continue building soil health and function.

They aim to reduce the emissions associated with their production and supporting biodiversity, potentially delivering more nutrient-dense produce.

“It’s a long-term game, but we are enjoying how things are changing and what can be achieved,” says Tom.

“Creating a resilient farm that supplies nutritious food through shorter supply chains, with local engagement, is the ambition.”