Title: EXTRACTABLE FORMS OF Al AND Fe IN ACID WESTERN

Extractable forms of Al and Fe were studied in five soils from the Coast Range, and in two soils from the Willamette Valley in Oregon. Exchangeable Al was determined in a way which permitted a comparison of three different methods for its determination. Values for exchangeable Al obtained by the method of lirrited leaching by Lin and Coleman (1960) agreed closely with those obtained by the method of Skeen and Sumner (1965) which consists of successive extractions and extrapolation to obtain the exchangeable Al content. Values for exchangeable Al measured by the method of exhaustive leaching pro-posed by Dewan and Rich (1970) exceeded the Coleman values in differ-ent amounts depending on the amount of exchangeable Al present, and on the final slope of the extraction curves. Steep slopes were found in coastal soils containing amorphous aluminosilicates, indicating that these soils have a strong supplying power for exchangeable Al, Fro