Author: Clemmie Gleeson

Organic farmer and seed producer Anna Pearce joined the TRUTH project as she was keen to work with scientists to learn more about the health of the soil on her farm.

She says: “As farmers we don’t often get the chance to interact with scientists and this is a huge opportunity to be able to put our heads together,” says Anna Pearce.

Becoming a Root Ranger followed success with a previous BOFIN project, working with researcher Dr Tom Thirkell from Crop Science Centre. This one looked at arbuscular mycorrhizal fungi populations and saw 41 farmers sending in root samples for analysis.

By joining TRUTH Anna was keen to develop this knowledge further and was interested to find out how her soil compared to other farms. Her trial of choice in year one was to assess the effect of biostimulant Fixio.

“It was actually the third year I tried this product. I was too late in the first year, but got good results in the second year with a 24% yield increase.” However yield is just one element – the addition
of the soil and root analyses available to her as a Root Ranger give a more detailed view of` how the soil and roots performed.

Anna carried out four replications in the field. “I believe that the more replications you have the more scientific the results. It’s just one spray so it’s not difficult to do.” She uses a yield monitor on her combine to see the yield variation between the treated and untreated areas.

For next harvest, Anna is using ADAS’ Agronomics for a more precise yield analysis of the treated and untreated areas.

The soil core CT scans have been another highlight for Anna.

She says: “It is fascinating to see pictures of what is under the ground. And it was reassuring to learn that my soil copes well with being lightly ploughed and that there is enough life in it to repair any changes to structure.”

As an organic producer, a min- till approach is not an option because of the weed burden, so gaining better understanding of the areas that can be changed has been invaluable, she adds.

“It shows that you can make a huge difference to your crops by having soil in the best conditions within your own parameters.”

Thornton Farm/ Smales Organic Seeds

• 280 hectares arable crops Organic production

• Wheat, barley, oats, beans grown primarily for seed

• Around one-third of the farm under clover

• Clover leys rented for sheep grazing

Arable farm manager Ted Allen-Stevens was keen to find out if ‘regenerative’ was the best way to go for soil and crops.

Owned by regen advocate Ian Piggott, Thrales End Farm had been managed according to regenerative principles for around nine years. But after joining as farm manager in 2023 Ted wanted evidence into how effective those practices had been in improving soil health.

As son of BOFIN founder Tom Allen-Stevens, Ted was well- versed in the value of on-farm trials. “Researchers can provide evidence of the value of regenerative practices, but every farm is unique, and I needed to see results from our system to know if it’s achieving its goals,” he says.

In year one of the project Ted joined the other farmer triallists
at training workshops learning about the different sampling techniques. Back at Thrales End his trial explored the effect of Polysulphate fertiliser on below-ground biomass taking samples from treated and untreated areas.

“Even though I didn’t see any significant differences between the two treatments it did provide me a valuable opportunity of setting up, completing and assessing on-farm trials,” he says.

By taking soil cores and both soil and root samples, he got a closer look at the health of his soils and roots. He also learned how to make sense of the data with guidance from the TRUTH scientists, which is proving particularly valuable.

“When I saw our results from the TRUTH project I felt that I had some real evidence that soil health had improved since we brought in regenerative practices here.

“It’s only when you drill down into the detail of your own farm that you can get that substance and reassurance of what you’re actually achieving.”

With another year of the project ahead, Ted’s hoping to fit together the pieces of his soil puzzle. He is exploring different nitrogen rates on the soil health and performance of different varieties but ultimately, he wants further depth to the evidence that regenerative principles are really paying off.

“This year I hope to tie in the scientific detail from the TRUTH project with changing or influencing our on-farm practice to reduce inputs and increase crop resilience.”

Thrales End Farm

• 400ha, sandy clay loam

• Wheat, oats, beans and stewardship schemes

• Regenerative system
• Direct drilling

Dr Maria Hernandez-Soriano is leading a fascinating investigation into soil microbial diversity as part of the TRUTH project. Her work involves analysing DNA from soil samples collected by Root Rangers across 10 farms, revealing a staggering 15,686 individual species.

The research aims to understand how different farming practices impact soil biodiversity, with early results suggesting that management practices, particularly organic farming, significantly influence microbial diversity.

In year one of the project, Maria assessed samples from the rhizosphere and different parts of the field taken by the 10 Root Rangers. “We were looking at the microbiome across all 10 sites and then assessing each farm individually for differences between them.”

With each of the Root Rangers sending 22 soil samples, Maria and colleagues had 220 samples to analyse. At the John Innes Centre laboratories in Norwich the samples are carefully processed to extract the DNA. The DNA is then prepared for sequencing by specialists to ensure the best quality analysis, and finally sent to a leading provider of sequencing services.

The scientists then compile a ‘library’ of all the DNA found in
the samples, naming matched sequences using extensive databases. The result is a vast spreadsheet listing all the individual microbial species found in each sample – a total of 15,686 across the Root Rangers’ soils.

The next task was to analyse that data, drawing comparisons across different systems and the whole dataset, but also drilling down into individual farms’ results to assess and compare diversity.

The first year of the project has gone well, she says. “At the moment the results are suggesting that management is the strongest influence.” In particular, the organic farmers amongst the Root Rangers had the most diverse samples with a significant difference in nitrification too.

Diversity is important because these microbes work together as part of a complex network, both in cooperation with each other and regulating their different roles in soil.

“It’s a huge community – some of which we know a lot about while others are yet to be characterised.”

Year two of the project is focusing more on the rhizosphere and now with 20 Root Rangers on board the sampling is producing an even stronger dataset.

“Working on the TRUTH project is a dream,” says Maria. “The farmers have been brilliant, and have sent us quality samples meaning that scientists like me can focus on what we do best. Through our work together we can deliver information that is of real value to farmers.”

Upcoming TRUTH trials

In year two of the project, novel wheat varieties are being multiplied up ready for trialling on Root Rangers’ farms in the final year of the project. These include a ‘remarkable’ variety that can regulate its own nitrogen supply.

Originating from Iran, this particular wheat landrace is part of the historic Watkins collection at JIC.

Maria explains: “What is interesting about this particular wheat, is that it has demonstrated capacity to decrease the transformation of ammonium into plant-available nitrate in the soil. This is believed to be an adaptive trait.”

It means much less nitrogen from fertilisers potentially being lost
to the environment and more being taken up and used by the wheat plant itself, because it is controlling the chemical transformation in soil and optimising the uptake.

“We haven’t observed that same capability or trait in any commercial wheat cultivars yet, so that is remarkable!”

The Root Rangers have been given a unique view of their soil structure and root systems through X-ray Computed Tomography (CT) scanning.

Dr Craig Sturrock of the University of Nottingham explains that CT scans were used to compare soil ‘cores’ from the different farms. The farmers took samples from their chosen fields of first winter wheat using sections of plastic pipe (15 cm x 8 cm). These were hammered into the ground before being carefully excavated to preserve the structure of the soil and roots inside. Each of the Root Rangers took 10 samples in a typical w-formation, five samples from the treated area under scrutiny in their trials and five from the untreated area. These samples were then posted to the University’s laboratory for scanning.

Craig explains: “It’s been a really exciting first year of the project, using the imaging technology to visualise the structure of soils across the UK, completely non- destructively, which is usually really difficult to see.

“We’ve found some nice differences between the soils. There’s variations between geographical location, soil texture, treatments, and differences in the root structure.”

CT scanning is a non-invasive technique to look at the structure and interior of the sample. It discriminates different materials based on density so more dense areas of materials appear brighter in the images. Soil pores, which are low density, appear darker. A high-powered computer then turns those 2D images into a 3D visual to show us what’s going on under the ground.

Analysis of the CT scan images measured the average porosity of the soil cores at typically 6% across all samples. It also measured mean pore thickness, orosity and connectivity of the pore network.

The scans highlighted the importance of biopores – channels created by roots and soil organisms – in soil health. These structures were evident across different soil types and management practices, providing pathways for root growth and water movement.

There was also evidence of healthy soil ecosystems, with numerous signs of biological activity. “There’s certainly lots of evidence of earthworms,” adds Craig. “There’s lots of biology there, keeping the soils nice and healthy.”

Different soil textures exhibited distinct characteristics in the scans. For instance, clay soils showed a blocky structure, while sandy soils displayed a lot of coarser grains.

The research highlighted the impact of management practices, such as ploughing and grazing.

The results were not always as expected, with ploughed soil showing minimal differences to min or no-till. This may have been related to the time of sample collection being relatively late in the growth season (May 2024), where the soil has had time to settle after cultivation the previous autumn.

In year two the Root Rangers are repeating the sampling process, but this time with five soil cores just from untreated areas. Sampling is taking place in March so tillage differences between sites may be more apparent.

“I’m really looking forward to seeing how the results will look and what more we can learn from repeating the sampling,” notes Craig.

Unearthing the secrets of the soil microbiome comes a step closer when farmers and research scientists work together, and the TRUTH Project has already revealed some intriguing results.

Dr Tom Thirkell’s area of expertise is mycorrhizal fungi – microscopic organisms that form symbiotic relationships with plant roots, facilitating nutrient exchange that is crucial for crop growth. His study within the TRUTH project aims to quantify the extent of these interactions, providing farmers with unique information about their soil’s microbiome.

The team of Root Rangers collect samples from their fields – digging up wheat roots, before washing and drying them, and then posting them to the laboratory in Cambridge. The research team then uses selective staining techniques to highlight the fungi within the roots, identifying structures such as hyphae, arbuscules and vesicles to indicate the level of nutrient exchange taking place.

“In a mutually-beneficial relationship, the plant supplies the fungi with carbon and receives essential nutrients like phosphorus and nitrogen in return,” explains Tom.

Mystery organisms

As well as healthy populations of mycorrhiza, Tom’s analysis of the Root Rangers’ samples has also uncovered some unidentified organisms.

“Selective staining works really well for the species of fungi that we work on, but every so often we find things we haven’t seen before.”

Some of these appear to be bacteria, while others are likely to belong to an ancient but newly- described group of fungi known as Mucoromycotina.

“We believe these can also form beneficial interactions with cereal crop roots, but there has been very little study of them compared to the arbuscular mycorrhizas.” They were found in several samples and are not unique to a specific type of farm, he explains.

“They are random how they crop up, but a strength of this project is that we can repeat these tests in years two and three and see if there are any patterns.” Tom also hopes that DNA sequencing of these samples may be possible in future, so that the ‘unknown fungi’ can be identified.

“Until then it’s our best guess what they might be.”

Tom’s findings from year one suggest that variations in fungal presence are influenced more by individual farms’ management practices, rather than the different treatments being trialled, but repetition of sampling in years two and three will develop this understanding further.

“There is a lot going on underground, but it can be uncovered through collaboration with farmers and other researchers through projects like TRUTH. It’s been well-documented that farm management impacts the microbiome. Moving forward, with an increased focus on sustainability and reduced chemical use, it is going to become more important.”

Microorganisms under the microscope

Hyphae: Fungal filaments which grow through the soil and
into plant roots that transport nutrients.

Arbuscules: Very small but highly branched structures within plant cells, that allow nutrient exchange.

Vesicles: Organs used by fungi for carbon storage to ensure a good supply, even when annual plant roots have died off

A revolutionary soil health analysis tool that can ‘smell’ a soil’s biological signature is being put through its paces by the TRUTH project’s Root Rangers.

PES Technologies developed its system to allow farmers and agronomists to carry out quick, cost-effective soil tests in the field. The system negates the need for farmers to send samples away, producing accurate results in just five minutes.

The hand-held, battery powered system is controlled with the smartphone app ScentsCheck. Put simply it ‘smells’ the soil, detecting volatile organic compounds and small molecular gases. This ‘smell fingerprint’ is captured and run through PES’s machine learning to provide more than 10 key biological and non-biological soil health indicators in a single test.

A small, representative sample is taken from the top 5-15 cm of soil and placed in the sensor’s soil drawer. After just five minutes it provides comprehensive information about the sample’s organic matter, microbial biomass and bulk density.

In addition, every sample also includes the GPS coordinates of where it was taken, making it easy to track how the soil’s health changes over time.

PES Technologies CEO Andrej Porovic says: “Getting the results straight away means you’re given intelligence of what is happening in a field while you’re stood looking at it.

“Everybody can see what’s going on above ground, but not what’s going on below – we want everyone to be able to see both at the same time to help them make decisions. We’re really looking forward to hearing how the Root Rangers get on with the sensor.”

Read more about the Root Rangers experiences on The Soil Circle on The Farming Forum or join the BOFIN WhatsApp community.