Conifer Tree Seedling Response to Nursery Soil Amended with Composted Sewage Sludge1

Seedlings of Norway spruce ( Picea abies (L.) Karst) produced longer stems when grown in seedbeds amended with 224 dry MT/ha screened composted sewage sludge or top-dressed with 1 MT/ha of Osmocote 18–6–12 or 112 dry MT/ha of screened composted sewage sludge applied at the end of the first growing season. More seedlings of white pine ( Pinus strobus L.) were produced in soils amended with 112 dry MT/ha of unscreened composted sewage sludge than in soils amended with 448 dry MT/ha of screened composted sewage sludge or in the 0 treatment levels. Soils amended with composted sewage sludge had higher pH, Mg, and P level than soils top-dressed with Osmocote 18–6–12 and mulched with pine sawdust.