Tuesday, November 14, 2006

Interaction of Organic and Inorganic P on Iron and Aluminum Oxides, and Kaolinite.

Branly Eugene, Brad Joern, Cliff Johnston, and Darrell Schulze. Purdue University, 915 W. State St., W. Lafayette, IN 47907

Phosphorus loss from soils can negatively impact surface water quality. Clay minerals and amorphous Fe- and Al-oxides largely control P sorption by soils. Our objective was to determine the sorption of inorganic P and three organic P compounds (adenosine triphosphate, ATP; glucose 6 phosphate, G6P; and inositol hexaphosphate, IHP) when added individually (noncompetitive) or in various combinations (competitive) to ferrihydrite, kaolinite, goethite and boehmite using 24 hour sorption isotherms. Preliminary data analysis of the noncompetitive isotherms showed that IHP had the greatest affinity for P sorption sites in all four mineral compounds. Preliminary data analysis of the competitive isotherms showed that IHP sorption was least affected by the presence of other P compounds and that ATP decreased inorganic P sorption more than IHP or G6P. The results and implications of this study will be presented in this poster.