Soil Ecology Research

Although we tend to think of soil as just dirt, soil is really alive with communities of bacteria, fungi and animals. In one teaspoon of soil there can be billions of bacteria and thousands of species.

Many of these bacteria and fungi are beneficial to plants. Healthy soil and healthy soil food webs are essential to maintain the health of our natural and agricultural lands.

But we still don’t really understand the role of most of these fungi in soil. Researchers at Holden are studying the diversity of fungi in soil, how human activities affect these fungi, and how the fungi affect soil fertility.

Many fungi colonize the roots of plants and provide them with nutrients from soil. These fungi – called mycorrhizal fungi (fungi on roots, literally) are found on 85 percent of all plants and are beneficial to plants.
Research at the Arboretum has found more than 3,000 species of fungi on the roots of trees, like oak and beech. But we still don’t really understand the role of most of these fungi in soil.

Ectomycorrhizal fungi colonize many tree roots and cover the root like a glove would cover your hand. Many of these species can be distinguished based upon color and appearance. Researchers at the Arboretum used DNA-based techniques to explore ectomycorrhizal fungi and their diversity. These roots were found on hardwood trees in Ohio.

Mushrooms are the reproductive structures of many soil fungi. These mushrooms were found in the Stebbins Gulch natural area. Left, Russula sp.; middle, Tremellodendron pallidum; right, Strobilomyces floccopus.

Arbuscular mycorrhizal fungi within the roots of herbaceous plants (Jack-in-the-pulpit panel A; Mayapple panel B; Sweet White Clover panel C). Arrows point to arbuscules which are the site of nutrient exchange between the plant and the fungi. These fungi are beneficial to plants and help them acquire nutrients and resist disease.

Ectomycorrhizal fungi on roots of beech and oak  (Inocybe sp. panel A; Russula sp. panel B; Cenococcum geophilum panel C).