Earthworms are the most obvious indicator of soil health, but Fuller is focused far beyond that, extending his concerns to the microbes and other unseen forces in the soil. “Gail realizes that the soil is an ecosystem,” observes Ray Archuleta, NRCS conservation agronomist based in Greensboro, S.C. “He shows us how to farm in nature’s image, how to collaborate with it, how to give more than you take.”
Fuller describes his foray into soil health as a journey of understanding. “When we first started into cover crops in the late 1990s, it was because we were just looking for something to cover the soil, to help slow down our soil erosion,” he says. “When we came back to cover crops in the mid-2000s, I learned more about nutrient cycling and water infiltration, and to get to things like that we needed more than just a monoculture.”
He learned to use mixtures of cover-crop species – Fuller calls them cover crop cocktails – designed to provide specific services in the soil. “We started out with three- and four-way mixes, and now it is not uncommon for me to plant a 12- or 15-way mix.”
The mixes can be separated into broad categories:
- Brassicas, such as radishes, turnips or kale
- Grasses, which can be warm-season species such as sudan or millet, or cool-season grasses such as oats, rye or triticale
- Broadleaf components, which could be legumes such as clover or alfalfa, or a non-legume broadleaf such as sunflower
Each brings its own contribution to soil health. Brassicas boost earthworm populations, for example, while some grass species favor the highly desirable arbuscular mycorrhiza fungi that assist plants in gathering nutrients from the soil.
Fuller is venturing into biological soil testing, having sent samples to Ward Laboratories where they undergo a phospholipid-derived fatty acids (PLFA) test. PLFA measures an essential structural component of all microbial cellular membranes, and PLFA analysis is a technique widely used for estimating the total biomass and community composition of soil microbes.
“Through those tests, we have learned that our predator/prey counts in the microbes are to the point that we no longer need seed treatments,” Fuller says. “The cover crops and companion crops draw in beneficial insects to control pests, which has allowed me to greatly reduce my pesticide use since we have good predator/prey counts above the soil. Now, we’re seeing we’ve also got those good counts below the soil surface.”
Fuller is backing away from seed treatments on all his cash crops. “We’ve not used seed treatments on our wheat for a couple of years, “ he says. “We started going away from it on soybeans last year, and won’t put seed treatments on soybeans for 2013. And we’ve got one company that is going to sell us some corn without seed treatment.”