Fungal response from oat (Avena sativa) plants and surface residue in relation to soil aggregation and organic carbon

The influence of soil fungi on soil organic carbon (OC) from surface residue was tested in outdoor plots in southern Ontario, Canada, 2004. Fungal hyphal length, soil aggregation, OC and light and heavy fractions of organic matter were compared with factors of plant growth (with or without oat [Avena sativa]) and surface residue (no residue, oat straw (low C:N) or corn (Zea mays) stalks (high C:N)) in a factorial arrangement. Significant increases were observed in soil OC from the oat plants, and from corn stalks compared to straw residue, in the growing season with very moist, high OC, sandy soil. In treatments with corn stalk residue, fungal hyphal length was increased with interaction from the oat plants and residue and was positively correlated with the heavy fraction organic matter along with soil OC. Fungal hyphae, plant roots and high C: N residue were all factors in soil OC increases.