Development and Testing of EQ Biosolids Mixes for Amending Disturbed Urban Soils and Improving Tall Fescue Drought Resistance.

Establishment of resource-efficient lawns and landscapes after the soil disturbance activities of urban development is often challenging. Topsoil is often not replaced, leaving a compacted soil with low organic matter. Class A, Exceptional Quality (EQ) biosolids for application to publicly accessible landscapes are from domestic sewages that have been processed to meet the most stringent of EPA regulations in terms of concentration limits for pollutants, pathogens, and vector attraction. Unless heat-dried or composted, EQ biosolids contain too much water to be spread effectively in landscape situations. Preliminary greenhouse research indicated that mixing 50% (v/v) EQ biosolids with 25% sand and 25% sawdust resulted in a low-moisture product with a C:N ratio that was favorable for tall fescue (Festuca arundinacea) development and growth. Our objective is to amend a disturbed urban soil with variously prepared biosolids applied at agronomic N or P rates and compare their effects on tall fescue establishment and persistence when subjected to drought or not to a synthetic fertilizer control. Topsoil was removed and plots (RCBD, with four replications) were amended to a 10 cm depth with: 1) Urea to supply agronomic N rate of 224 kg ha^-1 over the growing season; 2) EQ biosolids-alone at 224 kg PAN ha^-1; 3) EQ biosolids/sand/sawdust mix at 224 kg PAN ha^-1; 4) EQ biosolids/sand/sawdust mix at agronomic P rate of 64 kg N ha^-1, supplemented by 160 kg N ha^-1 over the season; and 5) biosolids compost at 224 kg PAN ha^-1. Following a September through May irrigated establishment period, plots were split to provide 80% of ET twice weekly or no irrigation. Drought resistance will be quantified in terms of tiller density, NDVI, chlorophyll and auxin concentrations, and root mass.