About the Fungal-to-Bacterial Biomass Ratio
The Fungal-to-Bacterial Biomass Ratio (or F:B Ratio) refers to the balance between fungi and bacteria in the soil, which plays a crucial role in soil health and plant succession.
Research has shown that a the F:B Ratio is a key indicator of soil health. As the F:B Ratio increases from 0:1 to 1:1, plant health improves and weeds are outcompeted by row crops like vegetables and herbs. That's because each plant has a specific F:B Ratio that it prefers, according to where it comes in the stages of plant succession. So what is plant succession?
Plant Succession
Plant succession is a natural process that occurs in ecosystems over time. It refers to the gradual change in plant species from weeds to bushes to trees and eventually to old growth forests. With each stage of succession, more and more plant material accumulates on top of the soil, giving the fungi the food it needs to increase its biomass.
During plant succession, different plant species establish and replace one another in a predictable sequence. Different plant species have unique root exudates and litter inputs, which shape the microbial community structure and function. For example, early successional plants may have a higher abundance of nitrogen-fixing bacteria, while late successional plants may have a greater reliance on mycorrhizal fungi.
This diagram shows the various stages of plant succession and the F:B Ratios that go along with them. Bacterial dominated soils are only good for growing weeds and annual grasses. Balanced soils with a 1:1 F:B Ratio are considered optimal for most vegetables, herbs, and crops that you might want to grow on your farm or in your garden.
Once you start approaching the 5:1 range, edge-of-forest plants like shrubs and berry bushes start to thrive. Soils like these are perfect for blueberry farms.
At 10:1, fruit trees start to thrive. Whether you have an orchard or just a few fruit trees in your backyard, you should be looking to nurture the fungi in your soils.
Lastly, old growth forests can have an F:B Ratio as high as 10,000:1, what we call fungal dominated. These old growth trees have a symbiotic relationship with mycorrhizal fungi, which have been referred to as the logistics system of the forest.
Measuring your F:B Ratio
Measuring your F:B Ratio (a key metric in Mycoscope's soil microbiome tests) can help you understand why certain plants are thriving and others are being outcompeted. By promoting the growth of beneficial fungi, farmers and gardeners can increase their crop health and yields, improve ecosystem resilience, and reduce their reliance on chemical inputs.
Based on the results of our soil microbiome tests, we provide tailored recommendations to improve the F:B Ratio in your soil. These recommendations usually include preserving the fungi in your soils to increase this ratio, as most soils are sadly deficient in fungi due to modern agricultural practices.
Do most farms maintain an F:B Ratio of at least 1:1?
Most conventional farms are stuck in the 0:1 - 0.3:1 range due to practices such as tilling the soil, which destroys the delicate fungal hyphae that stretch throughout the soil, as well as applying chemical pesticides, herbicides, and fungicides that destroy fungal communities. Fungi are far more sensitive than bacteria, which can bounce back even after being bombarded with chemicals. Thus, the key to improving your F:B Ratio, your soil health, and ultimately the health of your plants is utilizing practices that promote soil fungi. Let's work together to fuel that fungal feeding!
Mycoscope's team of soil microbiome experts is here to guide you on this journey towards an appropriate F:B Ratio for your crops. The first step is to measure your soil's F:B Ratio to establish a baseline, then following up with fungi-promoting practices and amendments, like no-till farming, no-dig gardening, and fungal-dominant composting. At Mycoscope, we believe in sharing knowledge. We don't gatekeep any "trade secrets". We will point you in the direction of many knowledgeable experts who have already discovered the path to increasing your F:B Ratio so that you can reap the benefits. Get your soil tested today and start on the successional path to truly healthy and productive plants!