Fraxinus americana Roots Respond to Subsurface Feeding of Mycorrhizal Inoculum and Nitrogen Fertilizer

Abstract Ball and burlap Fraxinus americana (Autumn purple ash) trees were evaluated for their response to subsurface feeding of mycorrhizal inoculum with root biostimulant (mycorrhiza Roots) and nitrogen fertilizer (Coron 28-0-0) on difficult sites in the Colorado front range. Two root ingrowth cores were installed around each of twelve trees following planting in fall 1998 and excavated in fall 1999. Inoculation with mycorrhiza Roots alone resulted in sigificantly increased dry root weights and mycorrhizal colonization percentage on treated purple ash trees (p ≤ 0.05). Mycorrhiza Roots with Coron also significantly increased dry root weights and mycorrhizal colonization percentage on treated ash (p ≤ 0.05). Increases in root growth were dramatic. Purple ash trees treated with mycorrhiza Roots and Coron had greater than 3.5 times the dry root weights in excavated root ingrowth cores compared controls. Trees treated with mycorrhiza Roots alone had greater than 3 times the dry weights compared to controls....