Pulp and paper sludge from a newsprint mill was composted for 6 weeks and evaluated as a substitute for peat moss in container media. One-year-old seedlings of lilac (Syringa vulgaris L.) and amur maple (Acer tataricum L. ssp. ginnala (Maxim.) Wesm.) as well as rooted cuttings of cistena plum (Prunus × cistena Hansen) were planted in #1 plastic pots that contained a pine bark and sand mixture (2:1 by vol) or pine bark and sand amended with either 25% or 50% peat moss or composted paper sludge. A 75% compost medium that consisted of composted paper sludge and sand (3:1 by vol) was also used in the study. Plant height was measured every 4 weeks. After 14 weeks of growth, shoot dry weight and final plant height were measured. All plants in compost-amended media grew as well as or better than those in peat-amended media, regardless of the species grown. Lilac plants in 25% compost produced almost double the amount of shoot dry weight and were 80% taller than plants in the bark: sand or 25% peat media. Maple plants in 50% compost produced at least 33% more shoot dry weight than those in either peat-amended medium. Plum cuttings in 25% compost grew at least 53% taller than those in either peat-amended medium. These results demonstrated that composted paper sludge from newsprint production was a worthy substitute for peat moss in a container medium for the three species tested.
Published as Idaho Agricultural Experiment Station Paper No. 95734. This research was supported, in part, by grants from the nursery industry through contributions of The Horticultural Research Institute, 1250 I Street, N.W., Suite 500, Washington, DC 20005. Plant donations by Carlton Plants and Bailey Nurseries, Inc. are gratefully acknowledged.
2Associate Professor and Scientific Aide Senior.
3Professor of Forest Products.
4Director of Statistical Programs.