Differentiating Between the Influence of Wear and Soil Compaction and Their Interaction on Turfgrass Stress.

Wear and soil compaction are major cause for turfgrass stress in maintaining athletic field turf. A field study was established on a silt loam (coarse silty mixed nonacid, mesic Typic Udifluvents) and sand rootzone in 2004 at the Joseph Troll Research Center, University of Massachusetts. The compaction treatments were applied using a plate vibrator compactor prior to seeding. The wear treatment was simulated with a steel brush set at a height to injure the leaves and guided over the plots by movable tracks. The plots were seeded with Kentucky bluegrass (Poa pratensis L.) and perennial ryegrass (Lolium perenne L.) in September 2004. Treatments were set out in a randomized complete block design with three replications. Plots were mowed at 30 mm height. Root biomass was reduced between 7.5 to 15 cm depth in the silt loam as a result of soil compaction. Root biomass was not affected by soil compaction in the sand. Penetrometer values recorded over 2004-2007 were significantly greater on the compacted versus the non-compacted treatment. There was a significant correlation (r = 0.82) between root biomass and penetration resistance in the silt loam at 7.5 to 15 cm depth. The compaction treatment significantly decreased air-filled porosity (AFP) and saturated hydraulic conductivity (SHC). There was a significant correlation (r = 0.95) between AFP and SHC. Percent of maximum dry density was used to assess the degree of soil compaction. This was significantly correlated (r = 0.57) to AFP in the silt loam and (r = 0.86) in the sand rootzone. Wear treatments imposed each month, June-November, resulted in significant injury in all months. However wear did not affect soil physical properties showing the methodology devised to apply wear differentiated between its influence and soil compaction on turfgrass stress.