If you’re no-tilling, soil biological activity in your fields is most likely better than your conventional tillage neighbors.

But to really increase the robustness of soil microbial life — and potentially increase nutrient cycling and crop yields — a more intensive crop rotation and diverse species of cover crops will do a better job than simply no-tilling monocultures, says Lisa Tiemann.

With a team of researchers, the Michigan State University Extension soil biologist recently studied the effects above ground plants have on below ground processes.

“A diverse community of soil organisms is going to help control plant disease, insects and weed pests, help form beneficial symbiotic relationships with plants, and there’s going to be recycling of nutrients and improvement in soil structure, as well as better water and nutrient-holding capacity,” says Tiemann.

Small World, Big Impact.

A teaspoon of soil has plenty of microorganisms that aren’t visible to the naked eye — more than 1 billion cells of bacteria and at least 10,000 different species, Tiemann says. There may also be up to 1 million different cells of fungi and up to 20 meters of fungal hyphae.

Predators of the soil underground, like protozoa, amoeba, flagellates, ciliates and nematodes, eat fungi and bacteria and release nitrogen (N) in a plant-available form. And larger organisms that are visible to the naked eye, such as mites and springtails, as well as moles and earthworms, are part of the soil scene and help complete the soil food web.