Biosolids-Based Amendments Effects on Tall Fescue Establishment in Urbanized Soil.

The removal of organic matter- and nutrient-rich topsoil and subsequent compaction of subsoil typically results in a poor plant rooting medium in urbanized landscapes. Exceptional Quality (EQ) biosolids were evaluated for renovating such degraded soils. A three-year study (September 2013 – June 2016) was conducted to compare various EQ biosolids with a standard inorganic fertilization system under two irrigation regimes (0 and 80% evapotranspiration) on (i) the quality and persistence of tall fescue (Schedonorus arundinaceus) and (ii) soil chemical and physical properties on a post-development soil classified as Groseclose silt loams (a clayey, kaolinitic, mesic Typic Hapludults). Five fertility amendments were applied at an annual establishment rate of 224 kg plant available nitrogen (PAN) ha^-1 (September 2013 – June 2015). No amendments were applied from June 2015 – June 2016 in order to measure residual treatment effects. Amendments included: 1) synthetic fertilizer applied according to Virginia Tech Soil Testing Laboratory (VTSTL) recommendations; 2) anaerobically digested, dewatered biosolids applied at the agronomic N rate; 3) anaerobically digested, dewatered biosolids blended with sand/sawdust applied at the agronomic N rate; 4) anaerobically digested, dewatered biosolids blended with sand/sawdust applied at the agronomic P rate and supplemented with inorganic N fertilizer to meet VTSTL recommendations; and 5) biosolids composted with wood chips. Turfgrass quality, yield, total leaf and soil C and N, normalized difference vegetative index (NDVI), soil nitrate and ammonium concentrations, and bulk density were measured. Biosolids-based amendments applied at the agronomic N rate elicited greater turfgrass yield and quality response than the inorganic fertilizer, and increased soil C and N concentrations, and reduced soil bulk density (p-value <0.05). Our results demonstrate that given time, application of biosolids-based products is a better approach to improve soil quality and turfgrass response than conventional inorganic fertilizer.