Monday, 6 October 2008: 9:45 AM

George R. Brown Convention Center, 362C

Michael San Clements, University of Maine, Dept. of Plant, Soil, and Env. Sciences, Deering Hall, Orono, ME 04469, Ivan J. Fernandez, Department of Plant, Soil and Environmental Sciences, University of Maine, Orono, ME 04401, Stephen Norton, University of Maine, Dept. of Earth Sciences, Orono, ME 04469, Aria Amirbahman, Civil and Environmental Engineering, University of Maine, Boardman Hall, Orono, ME 04469 and Lindsey Rustad, USDA-FS (Forest Service), 35 Crystal Lane, Cumberland, ME 04021-9538

Phosphorus (P) in acidic soils of forested watersheds originates from mineral apatite but is increasingly controlled by secondary aluminum (Al) and iron (Fe) as pedogenesis progresses. Research is underway to determine the relationship between illuvial secondary Al and Fe phases in these subsoils and P availability. We studied these relationships at eight watersheds in the US and Europe with varying parent materials, climates, vegetation, and histories of atmospheric acid deposition. Soil chemical fractionation techniques were used to determine labile-P, Fe-P, Al-P and apatite-P phases. The Al-P fraction was dominant in the B horizon of all watersheds with Al-P ranging from 68% to 82% of total extractable P. Evidence across all watersheds suggested that O horizon labile-P was correlated (r²=.54) with B horizon total extractable Altot (Altot=sum of Al in all fractions) despite differing site characteristics. There was a poor correlation between B horizon Altot and labile-P in the B horizon. This suggests bioavailable subsoil P is controlled by Al that is expressed through biocycling of P to the surface soils.

See more of: Forest Soil P Dynamics
See more of: S07 Forest, Range & Wildland Soils

2008 Joint Annual Meeting (5-9 Oct. 2008): Metal Controls on Forest Floor and B Horizon Extractable Phosphorus in Forested Watersheds.

596-2 Metal Controls on Forest Floor and B Horizon Extractable Phosphorus in Forested Watersheds.