Newsprint pulp and paper sludge as a soil additive/ amendment for alfalfa and bluegrass: Greenhouse study

Abstract

A newsprint, pulp and paper sludge was evaluated as a soil additive/amendment at 0, 8,15,31,62,123, and 246 Mg/ha for growth of alfalfa (Medicago sativa) and bluegrass (Poa pratensis) under greenhouse conditions. Bluegrass biomass increased by 300%, and protein content increased by 27% at 246 Mg/ha compared to the unamended soil. Alfalfa biomass was unaffected by sludge application rate, but protein content increased by 12%. No net nitrogen (N) immobilization was observed. A comparison of single and double exponential N mineralization models showed that the two pool model more closely fit the N mineralization data obtained from a laboratory incubation study. The two pool model was then used to develop linear regression equations to estimate appropriate sludge application rates based on the rate of N mineralization. © 1993, Taylor & Francis Group, LLC. All rights reserved.