Effects of sucrose and dried alum sludge on the growth of Rudbeckia and leaching of nitrogen and phosphorus from potting media containing biosolids compost

Sewage treatment biosolids are composted at 198 facilities in the United States (Goldstein 1998). Amending potting media, used in the commercial production of ornamental plants, with biosolids compost is considered a prime use (Bugbee 1996). Biosolids compost contains substantial amounts of the plant nutrients nitrogen (N) and phosphorus (P). If these nutrients leach from the potting media they can become a pollutant. Nitrate (N03-N) is the most common chemical contaminant in drinking water wells (USEPA 1990) and non-point sources of N may contribute to low oxygen levels in marine estuaries (Frink 1991). Phosphorus enrichment of freshwater ponds and lakes promotes the growth of nuisance algae (Frink and Norvell 1984). Strategies are needed to help prevent N and P in potting media containing biosolids from leaching to the environment.