ICOM1 Abstract

BERMAN, JENNIFER, CAROLINE BLEDSOE. Soils and Biogeochemistry, Dept. of L.A.W.R., The University of California, Davis, CA 95616. - The effect of forest soil inoculum on mycorrhizal root development and growth of valley oak seedlings A field experiment was carried out to assess the effects of riparian forest soil on ectomycorrhizal root development and seedling growth of valley oak (Quercus lobata N­e.). Soil collected from a mature riparian valley oak forest containing abundant potential fungal inoculum was put in acorn planting holes in an agricultural field. Two additional treatments were set up as controls: agricultural field soil and steam sterilized forest soil. When seedlings were harvested ten months later mycorrhizal roots were found in all three treatments. The greatest percent mycorrhizal infection and fine root biomass were found for seedlings grown in forest soil. Shoot biomass was greatest in the forest soil treatment and least in the agricultural soil, while biomass was intermediate for the sterilized forest soil. Our data suggest that mycorrhizal activity in the forest soil contributed to the increased seedling growth of the forest soil grown seedlings. The sterilized forest soil also contributed to growth through unknown mechanisms.