LAUSR

Assigned to Associate Editor Benjamin Wherley. Abstract Rehabilitating anthropogenically disturbed soils is vital to restore soil functionality and improve plant growth. Biosolids can be used to improve such soils and increase soil organic C (OC) stocks, but repeated applications of such organic byproducts may result in excess soil P. Here, we present further data that complete the observations for a 5-yr study (September 2013–October 2018) conducted on an anthropogenic soil tall fescue (Festuca arundinacea Schreb.) system. This study compared the effects of irrigation strategies (with or without irrigation during summer heat stress) and soil amendments (annual applications of biosolids products and a conventional synthetic fertilizer) for improving soil properties and tall fescue health. Biosolids amendments applied at the agronomic N rate (ANR) reduced soil bulk density at the 0to 5-cm depth by 33–53% and at the 5to 10-cm depth by 4–9% relative to synthetic fertilizer. Soil OC in the top 10 cm increased from 1.74 to 13.6 g OC kg−1 (i.e., +682%) over the 5-yr period for the conventionally fertilized tall fescue, and larger gains were observed in the biosolids treatments. Repeated applications of biosolids amendments at the ANR increased total P concentrations; however, biosolids containing high Fe concentrations did not increase water-soluble P compared with biosolids applied at the agronomic P rate (APR) and synthetic fertilizer after 5 yr. Biosolids amendments applied at the ANR improved tall fescue visual quality (maintained acceptable quality 86–92% of the time), clipping biomass, and leaf tissue N accumulation (P < .05).