Persephone Ma, 1991 Upper Buford Circle, University of Minnesota, St. Paul, MN and Carl J. Rosen, Department of Soil, Water, and Climate, University of Minnesota, St. Paul, MN
The Twin Cities incinerate sewage sludge for energy. Research has shown that the remaining biosolids ash, which is usually landfilled, can be a viable phosphorus source for crops. However, there are questions regarding the behavior of P release, the amount of plant available P compared to total P, and concentrations of metals of concern. To determine the viability of this ash as a P fertilizer, we conducted a 64 day soil incubation comparing this ash to conventional P fertilizer (TSP), dried pelletized biosolids, struvite, and a German ash product which has been thermochemically treated to decrease the metals content and increase P solubility. Each P source was applied at 40, 80, 120, and 160 lb P2O5/acre, with a zero-P control included, and soil samples were taken at 0, 2, 4, 8, 16, 32, 64 days. Samples were analyzed for available P and EPA 503 metals. Results from the first 32 days will be presented.