Plants depend on soil microorganisms in the root zone to produce various chemical compounds that regulate growth. Other soil microorganisms ward off parasitic nematodes and suppress disease. The mycorrhizal fungus wraps its hypha around plant root systems and thus protects them from root-feeding nematodes. Underground, nutrient retention occurs when bacteria and fungi multiply and convert free nitrogen from the soil into protein in their bodies, thus retaining nutrients. Nutrients are gradually released back into the soil and made available to plants when beneficial nematodes, soil mites, and protozoa eat the bacteria and fungi.
Soil microbes can also help clean up most herbicide and pesticide molecules.
Ingham's clients range from gardeners to commercial farmers. Preliminary research shows a correlation between restored soil foodwebs and improved crop resilience and nutritional quality. Increases of protein content in corn, wheat, strawberry, and grape crops have been documented. Yet Ingham and other soil scientists call for more research to meet the dire need for sustainable farming and food systems worldwide. Based on her experience with test plots, Ingham believes such research would prove the economic effectiveness of replacing many pesticides and fertilizers with sustainable soil management techniques.