Research Accomplishment Reports 2007

Mineral Controls on P Retention and Release in Soils and Soil Amendments

A.D. Karathanasis
Department of Plant and Soil Sciences

 

Project Description

The project seeks to improve our understanding of the processes controlling P partitioning at the mineral/solution interface (precipitation/sorption reactions), and the influence that such dynamic reactions have on other important co-contaminants, such as metals. Our research contribution was to investigate P sorption potential of Al-hydroxyinterlayered minerals, which are major constituents in the soils of the region. The results showed that most of these minerals have the capacity of sorbing both inorganic and organic forms of P, with higher binding affinity for organic than inorganic forms. In many cases this capacity appeared to exceed even that of free Al and Fe -hydroxides. The sorbed organic P forms also exhibited stronger retention by both Al-hydroxyinterlayered minerals and free Al and Fe-hydroxides. The findings suggest that soils dominated by such minerals may have a greater tolerance to receive higher P loads of organic wastes and a lower risk of polluting surface or ground waters.

Impact

Information generated by this research project will be of general utility in developing appropriate animal waste and nutrient management plans necessary to limit or avoid water pollution and generally improve environmental quality.

Publications

Karathanasis, A.D., D.M.C. Johnson, and C.J. Matocha. 2007. Subsurface Transport of Heavy Metals Mediated by Biosolid Colloids in Waste-Amended Soils. P. 175-201. In F. Frimmel, F. von der Kammer, and H.C. Flemming (eds.) Colloidal Transport in Pourous Media. Springer.

Karathanasis, A.D. 2008. Thermal Analysis of Soil Minerals. In Mineralogical Methods of Soil Analysis, SSSA (in press).

Karathanasis, A.D. 2008. Structural Allocation of Clay Mineral Elemental Components. In Mineralogical Methods of Soil Analysis, SSSA (in press).