Turfgrass Sod Harvesting and Land Use Sustainability.

Sodded landscapes provide immediate ecological and aesthetic benefits compared to seeded landscapes although both reduce soil loss and increase soil organic matter and hence soil quality following establishment.  The sustainability of continued sod harvesting is in question, given the high amounts of topsoil lost with each harvest compared to established soil loss tolerance (T), particularly, for shallow soil profiles.  We evaluated the effects of soil texture (silty-clay loam-SiCL, clay loam-CL, silty clay-SiC, and loamy sand-LS); slope (1%, 2% and 5%); and organic matter levels (low, medium and high) on soil loss and soil organic carbon (SOC) trends using typical turfgrass sod culture management operations from seedbed preparation but prior to sod harvesting.  The Revised Universal Soil Loss Equation version2 (RUSLE2) and its subroutine, the Conditioning Index (SCI), were used to evaluate soil loss and SOC trends respectively. The effect of turfgrass cutting depth and bulk density on soil loss and SOC trends from sod harvesting was estimated using the acre-furrow slice approach and SCI.  Annual soil loss before sod harvesting increased with slope but decreased with soil organic matter content and was significantly lower compared to conventional cropping systems.  Soil loss by texture ranked SiCL>CL≥SiC>LS.  Soil loss from sod harvesting, however, exceeded T values over the range of sod cutting depths, and soil bulk densities with significant decrease in SOC.  This suggests a need for strategies to reduce soil loss from sod harvesting that are economically feasible but improve or maintain soil organic carbon and land use sustainability.