By Tom Parker
That’s because the most critical processes involved in seed germination and plant health lie beneath the surface of the soil, and even then most can only be viewed on the microbial level through powerful microscopes. This hidden world—more a universe only now divulging its secrets, scientists say—is literally the root of all agriculture. But then, the term “root” might need to be redefined as well.
According to Larry Simpson, director of training and education for Mycorrhizal Applications, Inc., in Grants Pass, Ore., roots don’t do what people think they do.
“Getting nutrients and water from the soil is actually not a primary function of the root,” he said. “The root’s main function is to host mycorrhizal fungi, and the fungi’s task is to get nutrients and moisture from the soil. It’s a symbiotic relationship that’s relatively little known. Only in the past 50 years has it started to be understood, and the vast majority of that knowledge has come to light in the last 10 to 20 years.”
While the fungi is naturally-occurring, modern agricultural procedures such as extended fallow rotations, coupled with advanced tillage equipment and huge amounts of acreage under cultivation, have disrupted its vast interconnected web, Simpson said.
“Think of a huge dense spiderweb radiating out from the actual root of the plant,” he said. “The mycorrhizal filaments extend out a couple of feet from the host plant, so many in the growing season that there might be nine miles of filaments in a single teaspoon of native prairie soil. And they’re all interconnected, whether corn or wheat or soybean. Most of that population has been lost. We’re basically planting in soil that’s lost a critical component in how plants operate and perform. It’s a downward spiral.”
“The plant shares a small amount of sugar that keeps the fungus alive,” Simpson said. “Mycorrhizal fungi cannot feed themselves but require a living root to survive. If the plant dies, the fungus dies.”
Adding mycorrhizal fungus to the soil when planting seeds has several key benefits for farmers. In moist conditions the fungi acts as a primary immune system against fungal root disease caused by soil pathogens attacking the roots. In dry conditions the fungi allows host plants to not only tap into water sources more efficiently but even to store water for dry times, he said. The fungi promotes beneficial organisms that increase organic matter in the soil, thereby improving soil health, and they also help prevent potential effects from climate change through carbon sequestration.
“Farmers are always looking for better yield at less cost, and that’s what the fungi does,” Simpson said. “It increases the efficiency of the root system, enables individual plants to access more resources in the soil, improves growth in the host plant, requires less water and less fertilizer, further reducing costs. These are straightforward benefits no matter what kind of soil you have.”
Simpson suggests that farmers who are interested but not totally comfortable in adding mycorrhizal fungi to crops start by controlled planting in contiguous sections. “When treated and untreated crops are planted side by side, they will definitely see a difference,” he said. “Our approach is to ask the farmer to try a reasonable number of acres and plant it next to a crop treated without the mycorrhizal fungi and see for themselves. It slows down the overall process but gives them confidence when they see it happening.”
Though still in its formative years, research into mycorrhizal fungi continues to unlock secrets of the interconnections between plants, soil and microorganisms. Farmers wishing to educate themselves on cutting-edge techniques based on solid science would benefit from the one-day workshop, Simpson said.
“Certainly their fathers and their grandfathers and beyond benefitted from the fungus, because in their day the soil had a natural abundance,” he said. “It was part and parcel of the ways things worked.”
