RELATIVE EFFECTIVENESS OF SEWAGE-SLUDGE AS A NITROGEN-FERTILIZER FOR TALL FESCUE

A 3-yr study was conducted to determine which sludge rates would give yields of tall fescue comparable to yields obtained from inorganic N application. Sludge and NH//4NO//3 were surface applied at annual rates of 0, 110, 220, 440, and 880 (sludge only) kg N/ha. Dry matter yield of tall fescue from sludge-treated soils was 36, 56, and 50% of that on NH//4NO//3-treated soils for 1976, 1977, and 1978, respectively. Sludge was 27, 41, and 44% as effective as NH//4NO//3 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 NH//4NO//3 and usually increased toward the end of the growing season, but plant concentrations never reached toxic levels.