What’s often perceived as “bad soil” is more accurately a soil system that’s being prevented from functioning normally. Rather than being inherently poor, most soils have much greater potential for water retention, nutrient availability, and carbon storage than we realise. The issue is rarely a single factor like pH or low nutrients; those are symptoms of deeper, systemic imbalances.

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Soils are living ecosystems made up of billions of microorganisms, fungi, roots, and invertebrates. When these biological communities are disrupted, whether by physical limitations, chemical imbalances, or environmental stressors, soil function declines. This can suppress root growth, reduce microbial activity, and limit the natural cycling of nutrients and carbon. Even excess levels of nutrients like phosphorus can unintentionally inhibit beneficial plant-microbe relationships, such as those with mycorrhizal fungi, which are essential for soil health and structure.

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Understanding soil health requires taking a step back to assess the entire biological and chemical system. It's not just about fixing one metric—it's about restoring the soil’s capacity to function. By stimulating microbial life and encouraging robust root systems, we can reactivate these natural processes and unlock the soil’s true potential.

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This is why we developed Carbon Boost, to help soils recover by stimulating biology and promoting root activity, giving farmers a starting point to rebuild soil health and improve productivity over time.

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What is it?:

Soil microbial biomass is the total mass of living microorganisms in the soil, mainly bacteria, fungi and archaea. These microorganisms are important for soil health, as they contribute to nutrient cycling, the creation of soil structure and organic matter and play a significant role in carbon cycling and the formation and storage of complex carbons. Microbial biomass is a reliable indicator of the overall health and fertility of your soil. So how do you measure it and what is a good reading?

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Measuring Microbial biomass:

Microbial Biomass is not just about quantity. Two soils can have the same total microbial biomass but very different outcomes, depending on the diversity and activity of the organisms present. Active, diverse microbial communities contribute will have a greater impact positive on soil health than inactive or imbalanced ones.

One of the most accessible and cost-effective ways to measure microbial biomass is with a Microbiometer. This portable device pairs with a smartphone and provides results for around $10 per sample. It reports total microbial biomass in micrograms of carbon per gram (µg C/g) of soil and gives a snapshot of the fungi-to-bacteria ratio. While opinions vary, a balanced ratio, roughly 50:50, is often considered a sign of a healthy, functional soil. Skewed ratios may indicate a temporary disturbance or an underlying issue.

For most soils, readings above 500 µg C/g soil suggest a moderate to healthy level of microbial activity. Anything above 1,000 µg C/g is exceptional. Readings below 250 µg C/g may fall below the device's detection range and often signal a biologically inactive soil.

It's important to remember that soil biology is dynamic. Microbial populations and activity can change daily based on moisture, temperature, nutrient availability, and management practices. More advanced lab testing can offer species-level identification, but these results should be interpreted with caution, as microbial communities fluctuate rapidly.

Finally, one of the most underrated but reliable tools for assessing soil biological activity is your sense of smell. Soils rich in microbial life often have a distinct, earthy aroma, caused by a variety of aromatic compounds produced during microbial activity. Simply digging a hole and smelling the soil can provide instant insight into its biological condition. Healthy soil smells rich and complex; biologically poor soil often smells flat and dead.

Whether you are using a Microbiometer, or simply your nose, regularly monitoring microbial biomass can help guide management decisions and track the progress of soil health over time.