Temporal and Spatial Patterns in Forest Soil Response to Biosolid Amendments.
Michael R. Banaitis, Ivan J. Fernandez, and Cullen T. Wilson. Univ of Maine, Dept of Plant, Soil and Environmental Sciences, 5722 Deering Hall, Orono, ME 04469-5722
The use of biosolids as agricultural amendments has been studied extensively, yet applications in forests have not. This project is studying forest land application of N-Viro Soil™ (NVS), a Class A biosolid product that combines municipal sewage sludge, cement lime kiln dust, and coal-boiler fly ash. Twelve field plots were established in 2003 (Phase I) at 4.5, 6.7 and 13.4 Mg calcium carbonate equivalents (CCE) ha-1 and six field plots were established in 2005 (Phase II) at 20.0, 26.7 and 33.4 Mg CCE ha-1 . The forest is a twenty-year-old stand of hardwood dominated by quaking aspen (Populus tremuloides), gray birch (Betula populifolia), andred maple (Acer rubrum). Soil samples were collected and analyzed seasonally for pH. Annual or semi-annual soil and foliar sampling has been carried out to determine ecosystem response to treatments. Soil pH response in phase I plots initially paralleled loading rates in both the O-horizon and upper 5 cm of the B-horizon. Temporal responses varied by horizon, since pH responses in the upper B horizon were not evident until one year after application while O horizon responses were immediate. Three years after the Phase I application there was evidence of declines in pH from treatments. Phase II plots provide an opportunity to extend our understanding of the ecosystem response surface by using higher loading rates and results of both Phases I and II demonstrate temporal and spatial patterns of ecosystem change.