Biosolids Applications to Tall Fescue Have Long‐Term Influence on Soil Nitrogen, Carbon, and Phosphorus

• Published in: Journal of environmental quality 2013-03, Vol.42 (2), p.516-522
• Main Authors: Cogger, Craig G., Bary, Andy I., Myhre, Elizabeth A., Fortuna, Ann‐Marie
• Format: Article
• Language: English
• Subjects: Ammonium; Ammonium nitrate; Ammonium nitrates; Availability; Biosolids; Carbon; Composting; Equivalence; Fertilizers; Festuca arundinacea; Forages; Grasses; Manures; Nitrates; Nitrogen; Organic matter; Organic phosphorus; Phosphorus; Sludge; Soil; Soil (material); Soil organic matter; Soils; Uptakes
• ISSN: 0047-2425; 1537-2537
• DOI: 10.2134/jeq2012.0269

Repeated applications of biosolids provide long‐term benefits by increasing soil organic matter and N supply but can cause excess accumulation of P. Our objective was to determine the residual effects of repeated surface applications of biosolids on N availability and fate, tall fescue (Festuca arundinacea Schreb.) response, soil C, and P. A field experiment was started in 1993 to compare two biosolids products, each applied at three rates (6.7, 13.4, and 20.1 Mg ha−1 yr−1), with synthetic N fertilizer (0 and 403 kg N ha−1 yr−1 as ammonium nitrate). Treatments were surface applied for 10 yr, followed by a 9‐yr residual period where all plots received a reduced rate of inorganic N (202 kg N ha−1 yr−1). Annual measurements included forage yield, N uptake, and soil nitrate N. Soil samples collected in 2002 and 2011 were analyzed for total C and N and Bray‐1 P. Cumulative apparent N recoveries in harvested grass (1993–2010) were 51% for biosolids N and 72% for ammonium nitrate. Net fall soil nitrate N summed for the period 1993–2002 ranged from