1. Metal Controls and Acidity Controls on Forest Floor and B-Horizon Extractable Phosphorus in Forested Watersheds Michael D. SanClements 1, Ivan J. Fernandez 2, Stephen A. Norton 3 1 Dept. of Plant, Soil, and Environmental Sciences1 Dept. of Plant, Soil, and Environmental Sciences 2 Dept. of Plant, Soil, and Environmental Sciences & Climate Change Institute2 Dept. of Plant, Soil, and Environmental Sciences & Climate Change Institute 3 Dept. of Earth Sciences & Climate Change Institute3 Dept. of Earth Sciences & Climate Change Institute

2. Research Objectives Apply P fractionation techniques to an analysis of soil P, Al, and Fe across a suite of acidic soils in forested watersheds to determine: – chemical distributions of P among fractions – metal controls on P availability Better understand influence of changing chemical climate (e.g. acidic deposition)

3. ALPSS Project Sites (Aluminum and Phosphorus in Soils and Solutions) 1.Bear Brook Watershed in MaineMaine 2.Hadlock Brook Watershed Maine 3.Mud Pond WatershedMaine 4.Fernow Experimental Forest West Virginia 5.Strengbach WatershedFrance 6.Lesni PotokCzech Republic 1 3 2 4 5 6

4. Conceptual Sampling Design Stream Channel 0.1m1m3m10m Eight additional sampling points equidistant from each other 20m xxxxx 13 Pedons per transect 26 Pedons per watershed

5. Watershed Characteristics Upper B-horizon pH CaCl 2 : 3.4 to 4.1 Upper B-horizon % C: 1.1 to 8.9 Dominant Vegetation: Red spruce, Norway spruce, American beech, European beech Soil Orders: Spodosols Inceptisols

6. Phosphorus Fractionation Modified From Psenner (1985,1988) – 1M NH 4 Cl Labile-P – NaHCO 3 -Na 2 S 2 O 4 Reducible Fe-P – 0.1M NaOH Al-P, Fe-P P I – 0.5M HCl Ca-P – 1M NaOH Residual-P Murphy-Riley P T – P I =P O PTPT

7. Total Soil P by Watershed eab

8. Distribution of P by Fraction

9. pH, Al, and P

10. Linkages to Biology?

11. B-horizon Controls on Forest Floor P

12. Conclusions 1.The results suggest that Al controls P accumulation, and that Al dynamics are an important control on the biological availability of P 2.Any process or perturbation affecting Al within the ecosystem could directly alter P dynamics

13. Acknowledgements This research supported by: National Science Foundation Maine Agricultural and Forest Experiment Station With special thanks to: Mary Beth Adams, U.S.D.A Forest Service Tom Navratil, Czech Geologic Society Marie-Claire Pierret, University of Strasbourg Cheryl Spencer, University of Maine David Manski, National Parks Service