The Effects of Biosolids On Tall Fescue Sod Production and Soil Properties.

The amount of biosolids created by municipal wastewater facilities continues to grow each year while  suitable land in close proximity to the treatment facilities for biosolids application is increasingly difficult to find.  At the same time, sod growers  face rising production costs  that have reduced profitability.  Using biosolids to supply turfgrass nutrients and replace removed organic matter during sod production and harvest can alleviate these problems. The purpose of this study is to compare the effects of biosolids treatments and synthetic fertilizer on sod production.  Two biosolids products from the Alexandria Sanitation Authority, a class A dewatered cake and the same material blended with wood fines, were used at three rates designed to supply 0.5x, 1.0x and 1.5x the agronomic nitrogen rate (196 kg N ha^-1). Large field plots (61 m by 10.5 m) were established fall of 2009 and 2010 in a Kentucky bluegrass (Poa pratensis) and tall fescue (Festuca arundinacea) mixture on a sod farm in Remington, Virginia.  Turfgrass establishment, color, and quality, and broadleaf weed, grass weed, and disease pressure were measured bi-monthly throughout the growing seasons.  At harvest sod tensile strength, rooting strength and soil loss data were collected.  Soil phosphorus was tracked to evaluate P build-up across treatments.  The 1.0x and 1.5x biosolids rates of both products produced similar establishment, color, and quality compared to conventional sod production practices.  None of the cake biosolids rates resulted in significant soil P build-up at the end of the first season’s harvest (2010).  Average soil loss following the first harvest (2010) for 2.54 cm thick cut sod was 189 Mg ha^-1.  These results suggest that acceptable quality sod can be produced using a biosolids-based system, while providing a beneficial biosolids reuse pathway. Further data will be needed to evaluate the potential for long term soil P build-up.