Ronald Strahan, Koske, Thomas J. | 4/28/2009 7:37:32 PM
As many turfgrass producers know, there are more than a few people who have the misconception that turfgrass sod harvesting is a form of strip mining. They are convinced that topsoil is depleted each time turfgrass is harvested. Some people think turfgrass farms have to periodically bring in topsoil to replenish their fields. What these people don’t realize is that the lower portion of harvested sod isn’t all soil, but a leafy portion attached to a thatch/root layer that normally measures ½ to ¾ inches thick containing only a bit of soil. Lou and Ginger Brooking of Brookmeade Sod Farm in Hanover County, Virginia, have been harvesting turfgrass on the same farm for over 40 years.
Grass roots are continually developing, dying off, decomposing and redeveloping. This new organic matter keeps soil microbes active and improves the soil's chemical and physical properties. Turfgrass sod production actually improves farmland soil by adding organic materials and nutrients. Dr. C. Richard Skogley’s research at the University of Rhode Island showed that when sod is harvested, most of the grass root system is left in the soil.
Researchers found that sod fields contained an average difference of 1.9 percent more organic matter. Work by Skaradowski and Sullivan found that sod production fields increased in organic matter with time. Assuming that a 6-inch depth of soil on an acre weighs 1,000 tons, then this represents 19 tons per acre returned to soil. Based on a five-year study, it could be concluded that the turfgrass sod operation had added the equivalent of nearly four tons of organic matter to the soil each year.
Skogley, C.R. and B.B. Hesseltine. 1978. Soil Loss and Organic Matter Return in Sod Production. University of Rhode Island, Kingston, RI .
Skaradowski, S. and W.M. Sullivan. 1995. The Effects of Commercial Sod Production on Soil Dynamics. American Society of Agronomy. Madison, WI. R.I. Agricultural Experiment Station #3186.