Soil microbes are what have built soil highways for efficient transport and storage of soil moisture, gases and nutrients. "Soil microorganisms decay organic matter and cycle nutrients back into forms that plants can use,” says Jill Clapperton, rhizosphere (root zone) ecologist and president of Rhizoterra, Lolo, Mont. “Tiny soil animals like protozoa, amoebae, nematodes and mites feed on organic matter, fungi, bacteria and each other. Together these activities stabilize soil aggregates, build a better soil habitat and improve soil structure, tilth and productivity.”
Soil microbes, fed by carbon, release crop nutrients that are strongly locked to soil calcium, iron or aluminum, depending upon soil pH, Nichols says. Without microbes, vital soil nutrients like P remain present but unavailable to your crop.