In modern agriculture, the health of the soil is recognised as the foundation of sustainable, profitable farming. Yet despite decades of research linking soil microbial activity to nutrient cycling, disease suppression, and crop performance, few farmers have access to a practical, affordable means of measuring it. The microBIOMETER® changes that — offering rapid, on-farm soil biology testing that delivers results within twenty minutes.
At Agricultural Supply Services, we work with arable, mixed, and grassland farmers across the UK to support better agronomic decision-making from field to store. One area we are increasingly asked about is soil health — and specifically, how to measure the biological component of soil health in a way that informs management decisions at the right time. This article explains what the microBIOMETER® is, why it matters, and how UK farmers can use it to drive measurable improvements in soil function and crop performance.
What Is the microBIOMETER®?
The microBIOMETER® is a field-portable soil biology testing system developed in the United States and now used globally by farmers, agronomists, and researchers. It measures total microbial biomass — the combined mass of all living bacteria, fungi, protozoa, and other microorganisms in a soil sample — as well as the fungal-to-bacterial ratio, which provides insight into the structure and maturity of the soil food web.
The test itself is straightforward: a small soil sample is diluted in a standard solution, stained with a fluorescent dye that binds to microbial cells, and viewed under the microBIOMETER® microscope at 400× magnification using a smartphone or tablet camera. The integrated app analyses the image, calculates microbial biomass in micrograms per gram of soil, and stores the result with GPS coordinates, date, and field notes for later reference.
The entire process — from sample collection to result — takes around twenty minutes. There is no need to send samples away to a laboratory, and there is no waiting period. The result is available immediately, which means you can make timely management decisions — whether that is applying a biostimulant, adjusting organic matter additions, or confirming that a cover crop has delivered the biological response you intended.
Why Soil Microbial Biomass Matters
Soil is far more than a physical substrate for anchoring roots and holding water. It is a living ecosystem — one in which microorganisms play a central role in cycling nutrients, decomposing organic matter, building soil structure, and protecting crops from pests and diseases. A single gram of healthy soil can contain billions of bacterial cells and metres of fungal hyphae, all working in concert to drive the biological processes that underpin crop nutrition.
When soil microbial biomass is high and diverse, several important benefits follow. Organic nitrogen is mineralised more efficiently, reducing reliance on synthetic nitrogen fertilisers. Phosphorus that would otherwise be locked up in unavailable forms is released through microbial activity and mycorrhizal associations. Soil aggregates are stabilised by fungal hyphae and microbial exudates, improving water infiltration and reducing erosion. And pathogens are kept in check by the competitive and antagonistic activity of beneficial microbes.
Conversely, when microbial biomass is low — often the result of intensive tillage, prolonged monoculture, or high inputs of certain synthetic chemicals — these processes slow or stall. Nutrient cycling becomes sluggish, organic matter decomposes more slowly, and the soil becomes more vulnerable to compaction, waterlogging, and pest pressure.
Measuring soil microbial biomass is not an academic exercise. It is a practical diagnostic tool that tells you whether your management is building or depleting the biological capital on which long-term productivity depends. The microBIOMETER® makes this measurement accessible. Rather than relying on expensive laboratory assays that take weeks to return, or attempting to infer biological health from indirect indicators such as earthworm counts, farmers can now obtain a quantitative, comparable measure of microbial activity within minutes — and use that data to guide amendments, monitor responses, and track progress over time.
Key Benefits of the microBIOMETER® for UK Farmers
The microBIOMETER® offers several distinct advantages to UK arable and grassland operations looking to integrate soil biology into their management toolkit.
Rapid On-Farm Results
Laboratory soil microbiology tests can take two to four weeks and cost £40–£100 per sample. The microBIOMETER® delivers results in twenty minutes for a fraction of the cost — enabling timely decisions during critical management windows.
Quantitative and Comparable
Rather than subjective assessments or relative rankings, the microBIOMETER® provides a numerical biomass figure in micrograms per gram of soil. This allows direct comparison between fields, management zones, and sampling dates.
Measure the Impact of Amendments
Cover crops, composts, biostimulants, and reduced tillage all promise biological benefits. The microBIOMETER® lets you verify whether they are actually working — test before, then retest weeks later to confirm the response.
Track Improvement Season by Season
Cloud-stored results create a longitudinal record of your soil health journey. Over seasons and years, you build an invaluable dataset demonstrating the return on your soil improvement investments.
Support SFI & Agri-Environment Claims
Objective, dated, georeferenced soil biology data strengthens your evidence base for Sustainable Farming Incentive payments and demonstrates responsible land management to processors and retailers.
Target Inputs More Precisely
Understanding which fields or zones have healthy biological activity — and which do not — allows you to direct biostimulants, organic matter, and other amendments where they will deliver the greatest return.
When and How Often Should UK Farmers Test?
Microbial populations are naturally dynamic, shifting with seasons, soil temperature, moisture, and crop growth stage. A single test provides a useful snapshot; a programme of regular testing reveals trends, confirms responses to management changes, and builds the baseline knowledge needed to manage proactively.
| Scenario | Recommended Testing Programme |
|---|---|
| Establishing a baseline | Test each field once before any amendments, ideally at the same time of year for consistency |
| Cover crops | Test before drilling, then again 3–4 weeks after establishment to measure the biological response |
| Liquid amendments & biostimulants | Test before application, then at 2 weeks and 6 weeks post-application |
| Solid amendments (compost, manure) | Test before application, then at 4 weeks and 8 weeks post-application |
| Reduced or no-till transition | Test at least twice per season across multiple years to track the biological recovery |
| Seasonal monitoring | Test pre-drilling and post-harvest as a minimum; add a mid-season test for actively managed fields |
Practical Tip: Always collect samples at the same depth and under similar moisture conditions for comparable results. Field-moist samples taken at 2–5 inches depth give the most reliable reading of the active root zone. Avoid sampling from wet patches, headlands, or areas directly adjacent to slurry or fertiliser application points, as these are not representative of the broader field.
Understanding the Fungal-to-Bacterial Ratio
Beyond total microbial biomass, the microBIOMETER® also provides the fungal-to-bacterial ratio — a metric that offers important insight into the structure and maturity of your soil food web.
Fungal-dominated soils tend to cycle nutrients more slowly, retain organic matter more effectively, and support better soil structure — characteristics associated with perennial crops, grassland, and regeneratively managed arable land. Bacterial-dominated soils cycle nutrients more rapidly and are better suited to annual cropping systems, but can indicate a soil that has been disrupted by intensive tillage or chemical inputs.
Understanding your ratio allows you to manage amendments deliberately. If you are transitioning towards reduced tillage or want to build the conditions that support mycorrhizal fungi — which are critical for phosphorus uptake — the ratio gives you a measurable target to work towards and a means of confirming progress.
Acting on Your Results
A microBIOMETER® result is most valuable as the starting point for a targeted management response. A low microbial biomass reading does not mean the situation is fixed — it means you have identified an opportunity. Common management interventions that consistently improve biomass scores include:
Cover cropping — diverse, multi-species mixes feed a broader range of microbial communities and protect soil biology over winter, when populations would otherwise decline.
Reduced or minimum tillage — every tillage pass disrupts fungal hyphae and the aggregate structures that protect microbial communities. Reducing soil disturbance is one of the most impactful biological management decisions available.
Compost and organic matter additions — feeding the microbial community with high-quality organic carbon is the most reliable way to build lasting biological activity.
Biostimulant and microbial inoculant applications — products containing beneficial bacteria and mycorrhizal fungi can accelerate recovery in depleted soils. The microBIOMETER® lets you verify whether your chosen product is delivering a measurable response.
Reducing synthetic inputs where possible — high rates of soluble nitrogen and certain fungicides can suppress microbial populations. Data from repeated testing helps identify where input reductions are viable without compromising yield.
Cost and Value: A Straightforward Case
The microBIOMETER® starter kit provides ten tests, with refills available in further packs of ten. The per-test cost is a fraction of conventional laboratory microbiology analysis, and crucially, the result is available within twenty minutes rather than weeks — meaning you can act on it within the same management window.
When you consider that improved soil microbial management is associated with a minimum 5–10% increase in crop yields alongside meaningful reductions in fertiliser and pesticide inputs, the return on investment from a structured testing programme is compelling. Even a single season of more targeted input decisions, guided by real biological data, is likely to recover the cost of the kit many times over.
Research into the use of biostimulants and improved soil microbial management consistently reports a 5–25% increase in fertiliser use efficiency, a 10–15% reduction in pesticide use, and a minimum 5–10% increase in crop yields. For a 500-acre arable unit, the financial implications of those improvements are very significant indeed. The microBIOMETER® gives you the data to pursue those improvements with confidence — and to prove they are working.
Getting Started with Agricultural Supply Services
Agricultural Supply Services supplies the microBIOMETER® starter kit and refill packs to farmers across the UK. Whether you farm arable, mixed, or grassland, and whether you are just beginning your soil health journey or looking to add biological measurement to an already sophisticated management programme, the microBIOMETER® is the most practical and affordable tool available for bringing soil biology into your decision-making.
We work with farmers across the UK as their Expert Farming Partner — supplying the tools and technologies that support better agronomic outcomes. Contact our team to find out more about the microBIOMETER® or to explore the broader range of soil health solutions we supply.