The Soil Microbiome: What It Is, Why It Matters & How Healthy Soil Can Help Save The World

Published on July 17, 2020

You may have been hearing the term "microbiome" a lot more recently. This has been a trending health topic across all media channels as new research continues to emerge showing how inextricably linked overall human health is to the health of the microbes in our gut. The gut microbiome contributes to our digestive, immune, and emotional health, so it plays a vital role in overall well-being.*

Soil, like our gut, has its own microbiome, which supports the health of the plants growing in it. And just as we have unknowingly destroyed key microbes in the human gut by consuming highly processed foods and from the widespread overuse of antibiotics, we have also carelessly damaged the soil microbiome through overuse of chemical herbicides, pesticides, fertilizers and fungicides, heavy plowing and tillage, and the failure to add organic matter back to the soil upon which the microbes feed.

On our 350-acre Certified Organic farm in Brevard, North Carolina, the health of our soil is just as important as the health of our plants. According to Thomas Leonard, Farm Operations Manager, “We are growing more life than just the plants we harvest. We are really repairing the entire ecosystem.” Come along as we dig deep into the soil microbiome and learn tips for improving soil health in your garden.

Understanding the Soil Microbiome

The soil microbiome is a complex interaction of the billions of microbial organisms found within the soil. There are multiple layers, or horizons, of soil, with the microbiome concentrated mostly within the first six inches. Those first six inches are referred to as the "A" horizon, or the topsoil. And in just one single teaspoon of topsoil, there are about 50 billion microbes. Although invisible to the naked eye, these microorganisms are essential to healthy soil. Each microbe is vital in the overall interaction between the microbiome and the plant roots, and together they have a symbiotic relationship. The soil microbiome lives off of the exudates from the plant roots. Exudates are organic substances secreted by the roots, including sugars, enzymes, and other compounds that support the interaction of the microbes and the roots. The microbiome is then able to produce the nutrients that the plant roots need, such as nitrogen, potassium, and phosphorus.

Two Big Reasons Why Soil Health Matters

Soil Health Can Combat Climate Change From the Ground Up

Maintaining a healthy soil microbiome isn't just important for the plants, it's critical for the environment. Soil high in organic matter with healthy microbial activity helps to trap excess carbon that would otherwise contribute to climate change. And as soil health improves, it is able to capture even more carbon in the atmosphere. This past year on our farm, we were able to capture over 2,490 tons of CO2 in the soil by supporting its microbiome. This is equivalent to the emissions from the electricity of 422 homes in a year. Leonard shared, “We farm almost as much carbon as we do all of the crops that grow on our farm. It’s satisfying to look at our soil tests year after year and see that we are sequestering even more carbon.”

Improving Soil Health Can Save Time & Money

Healthy plants need healthy soil to thrive. When soil is high in organic matter and a soil microbiome is alive with interacting bacteria, fungi, nematodes, and earthworms, plants are able to better absorb water, nutrients, and minerals. This allows the plants to essentially grow and flourish on their own, without extra assistance, because they are receiving the nutrients that they need directly from the earth. Soil microbes are also scientifically proven to improve the health of plants by fending off diseases, which in turn generates higher crop yields. As you can see, healthier soil is also healthier for your budget, as the reduced need for fertilizers, irrigation assistance, and the increase in crop productivity results in both cost and time savings.

Observing What Healthy Soil Looks Like

The easiest way to tell if your yard has healthy soil is by simply giving it a close inspection, as there are certain characteristics typically present in healthy soil, including:

  • Soil rich in organic matter with a strong microbiome will be dark brown in color. This color is an indicator that the organic material has been broken down and is readily available to nourish the microbiome.
  • From earthworms to fungi, healthy soil will include plenty of visible animal and plant activity as this is also an indicator of the overall condition.
  • The texture of healthy soil should be variable. This means that if you scoop up a handful of soil, you should see different textures and see various sized compounds. Differences in size and texture will come from the combination of earth materials that make up the soil in its entirety. When looking at soil overall, it is typically made up of approximately 25% air, 25% water, 5% soil organic matter, and 45% of a mixture of sand, silt, and clay. This mixture, referred to as loam, is about 40% sand, 40% silt, and 20% clay. Together, these materials create the variation of sizes and textures that you can look for in healthy soil.
  • Healthy soil will also have a balance of water retention and drainage, which is especially beneficial during dry seasons.

5 Tips for Improving Soil Health in Your Yard

Test the Soil

Testing your soil at home is a great first step to prepare for a new garden, or if you have noticed that an existing garden has not been doing well, it can help you determine why. According to Kate Renner, Assistant Farm Operations Manager, "When testing your soil, you want to make sure that it's a representative sample of the land. This can be done by digging about 6-8 inches down for samples in the four corners of your plot, as well as one in the center, and then mix it all together. For a closer look at this process, check out our Instagram page @gaiaherbs, where I go through the soil sample process used on our farm step-by-step in the highlight 'Kate's Turn'."

Brew Some Compost Tea

Compost tea is exactly what it sounds like, compost that has been steeped in water. Adding a compost tea to your garden helps to introduce beneficial bacteria to your plants and the soil because it separates the microbes from the rest of the compost, which would otherwise be difficult. Learn how to make your own compost tea at home.

Use Clippings as Mulch

There's no need to head to the hardware store for mulch. Instead, you can use what is naturally available in your yard. Yard debris and pieces from surrounding trees can be used and act as an effective mulch providing the soil with nitrogen. Mulch also provides a space for beneficial fungi to grow and encourages other symbiotic relationships between plants.

Practice Cover Cropping

Cover cropping in larger gardens is an effective way to use the space throughout the year, especially if your area experiences a change in the seasons. Clover, Rye, and Buckwheat are a few examples of cover crops used on our farm, and we recommend these for growing during off-seasons. Cover crops assist with soil health in providing a living root to be in the ground even in the offseason, allowing for root exudate exchange with the soil microbiome throughout the year, drainage/aeration for erosion control, and depending on the cover crop used, the addition of nutrients like nitrogen to the soil.

Allow Plant Matter to Naturally Decompose

Another way to encourage microbial growth within the soil is to leave fallen plant matter to decompose naturally. Allowing the plant matter to decompose helps increase the soil's organic matter and improve the microbiome's health. Learn more about our regenerative farming practices to improve soil health and other methods that you can incorporate at home.

Help The Soil, Heal The Planet

The solution to climate change may be right under our feet. By focusing on restoring soil health, we can all help improve the environment. And if you do not have the time to dedicate to your soil health, you can still make a difference. Another easy way you can help is by purchasing organic food and supplements from producers that practice environmentally responsible, sustainable farming methods. Organic farming makes the land healthier, whereas industrial farming keeps making it sicker. Through these efforts, big change can be created by the smallest of organisms.