Relative Effectiveness of Sewage Sludge as a Nitrogen Fertilizer for Tall Fescue

Abstract
Sewage sludge application rates on grasses are mainly determined by N availability and concentration of toxic metals in sludge. The exact availability of N in sludge is difficult to predict. A 3‐yr study was conducted to determine which sludge rates would give yields of tall rescue (Festuca arundinacea Shreb. ‘Alta’) comparable to yields obtained from inorganic N application. Sludge and NH4NO3 were surface applied at annual rates of 0, 110, 220, 440, and 880 (sludge only) kg N/ha. Dry matter yield of tall rescue from sludge‐treated soils was 36, 56, and 50% of that on NH4NO3‐treated soils for 1976, 1977, and 1978, respectively. Sludge was 27, 41, and 44% as effective as NH4NO3 as a source of available N in 1976, 1977, and 1978, respectively. Ammonium‐N in the sewage sludge apparently provided most of the available N for fescue growth. Concentrations of Zn, Cd, and Cu were higher and Mn lower in tall fescue grown on sludge‐treated soil with NH4NO3 and usually increased toward the end of the growing season. However, plant concentrations of these heavy metals never reached toxic levels at any time. Sewage sludge was an effective and safe nutrient source for tall fescue.
Funding Information
  • Portland and Salem

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