Effects of Soil Decompaction and Amendment on Root Growth and Architecture in Red Maple ( Acer rubrum)
William Hascher and Christina E. Wells
Abstract: The Terravent TMsoil injection device (Pinnacle Concepts, Ltd., Cornwall, UK) uses compressed nitrogen gas to fracture compacted soil and permits the subsequent injection of liquid amendments. In the current study, we measured fine root growth and architecture in soil that had received one of four treatments: 1) Terravent injections, 2) Terravent injections followed by liquid amendment (MycorTreeŽ Injectable; PHC, Inc., Pittsburgh, PA, U.S.), 3) addition of amendment only, and 4) an untreated control. The experiment was conducted on ten red maples (Acer rubrum) growing on a moderately compacted urban clay soil next to a busy road on the Clemson University campus. Treatments were applied in April 2002. Seven weeks later, soil cores were pulled from locations adjacent to the injection sites, and fine roots (less than 2 mm [0.08 in] in diameter) from each core were washed free of soil. A variety of root parameters were measured, including length, surface area, diameter distribution, and mass. Terravent treatment had no effect on any root parameters measured. Application of MycorTree was associated with small, statistically significant reductions in root diameter, root mass density (mg root/cm 3soil), and root surface area density (cm 2root/cm 3soil).
Keywords: Acer rubrum; root growth; soil decompaction