Nutrient-based yield theories have served agriculture for more than 150 years, but the problem, some soil scientists say, is those models were created without any concept of soil biology.

But with yields stagnating and soil health declining across much of the globe, soil biology might be the last frontier available to farmers for stabilizing and even growing yields, says Will Brinton, whose company, Woods End Laboratories, has pioneered new soil tests that measure soil biological activity.

Key Components

To grasp the potential of soil biology, the various components of organic matter and how they function, must be understood.

Organic matter (OM), a key linchpin for soil health, includes a humus component, plant root component and soil organisms.

Soil organisms make up about 5% of the actual organic matter, and the group includes algae, fungi, bacteria, actinomycetes and soil animals. All contribute to the respiration cycle and overall performance of soils.

Soil organic matter also includes crop and root residues, manures and any living detritus in the system, as well as the accumulated humus on which soil microbes are feeding continually. “There is no such thing as a dead soil,” Brinton says.

Soil biological transactions do many things at once. They furnish soil animals with food. The same cycle provides CO2 for plant photosynthesis and releases available nitrogen (N) and phosphorus (P) to plants, Brinton says.

“Even more interesting,” he says, “is that the CO2 builds up in soil and acts as a natural weathering agent or solvent, pulling minerals out…