NEWSPRINT PULP AND PAPER SLUDGE AS A SOIL ADDITIVE AMENDMENT FOR ALFALFA AND BLUEGRASS - GREENHOUSE STUDY

A newsprint, pulp and paper sludge was evaluated as a soil additive/am endment at 0, 8, 15, 31, 62, 123, and 246 Mg/ha for growth of alfalfa (Medicago sativa) and bluegrass (Poa pratensis) under greenhouse condi tions. Bluegrass biomass increased by 300%, and protein content increa sed by 27% at 246 Mg/ha compared to the unamended soil. Alfalfa biomas s was unaffected by sludge application rate, but protein content incre ased by 12%. No net nitrogen (N) immobilization was observed. A compar ison of single and double exponential N mineralization models showed t hat the two pool model more closely fit the N mineralization data obta ined from a laboratory incubation study. The two pool model was then u sed to develop linear regression equations to estimate appropriate slu dge application rates based on the rate of N mineralization.