Invisible Earth: Soil Microbes

Most people look at the ground and only see “dirt”. Gardeners know that it is much more; soil contains moisture, organic matter, and nutrients. It has specific textures and properties unique to not only large geographical areas, but also within a backyard! However, even gardeners can often overlook the importance of another soil component—microbes. They are at the end and beginning of soil food webs. Let’s dive into our invisible earth and learn more about our friendly soil microbes.

Fun Fact: A single teaspoon of soil contains more microbes than there are people on Earth!
soil microbes
Bacteria: These microorganisms are the smallest microbes in the soil, but are extremely abundant and important. They participate in the majority of breaking down of nutrients and make them available to plants. One of the key roles bacteria plays is fixing nitrogen for plants to access, since nitrogen in the atmosphere is not in a form available to plants. When bacteria in the soil process the nitrogen, they turn it into a form that plants can uptake. Without these nitrogen-fixing bacteria, few plants would be able to grow.  Bacteria retain other nutrients as well, which ensures that the nutrients remain in the soil and are not carried away by water before the plants have a chance to use them.

Actinomycetes: These are little-known microbes that function similar to fungi. They decompose decaying matter and prevent many plant pathogens from spreading through the soil. Actinomycetes are good at breaking down and removing pollutants from soils, such as hydrocarbons (e.g. oil). This way, they contribute much to making soil healthier and better-suited for susceptible plants.

Fungi: Often seen as negative, like mold. However, fungi plays a crucial role in the decomposition of dead plant and animal matter and returning nutrients to the soil. Mycorrhizae, one of the most common types of soil fungi, grow on plant roots and live symbiotically with plants— it increases surface area for more water uptake, and aids in making nutrients available to plants. In return, the plants supply the mycorrhizae some of the sugars and carbohydrates they produce. These are great for plants, but do best in undisturbed soil.

Protozoa: These microbes are multi-celled and act similarly to animals. They are carnivorous and move around searching for prey of bacteria and other protozoan. They help return nutrients taken up by bacteria to the soil, by eating and breaking down the bacteria.

Nematodes: These worm-like microbes are most often discussed in a negative manner for good reason. Many are pathogenic and will harm plant roots; but, there are also many beneficial nematodes that consume the “bad” nematodes and other grubs in the soil. They act as a biological control method, similar to how ladybugs can be used to manage aphid and mite populations.

While important, soil is often overlooked as a unique ecosystem. We focus on the world we can observe—the plants that grow from the soil, the insects and animals that surround them, and the harvest that we receive. However, so much occurs that is invisible to the eye yet has a considerable effect on the health of soil and the plants we grow in it. Having a better understanding of our soil microbes helps us create an environment where our plants can truly thrive.

For all your gardening and landscaping needs, shop at one of Big Earth Landscape Supply‘s 4 Sarasota and Tampa area locations.