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Soil phosphorus extracted by iron-aluminum-oxide-impregnated filter paper

Sharpley, A.N.
Soil Science Society of America journal 1991 v.55 no.4 pp. 1038
soil fertility, soil analysis, nutrient availability, phosphorus, filters, paper, absorption, iron oxides, aluminum oxide, calcareous soils, weathering, physicochemical properties, extraction, fertilizer requirements, genetic soil types, inorganic phosphorus, United States, Puerto Rico, Indonesia, Malaysia, Papua New Guinea, Philippines, Sudan
The use of Fe-Al-oxide-impregnated paper strips may allow estimation of plant-available P contents of soils with widely differing properties. Little information is available on the forms of P extracted by paper strips (SP). Relationships between SP and Olsen, Bray I, Mehlich III, and P fractions were investigated for 203 surface soils representing all soil orders. Soils were divided into calcareous, slightly weathered, and highly weathered groups, based on taxonomy and weathering. Amounts of P extracted by paper strips were closely correlated (r2 of 0.89 to 0.93, P > 0.001) with soil-test P (Olsen, Bray I, and Mehlich III), for soils on which use of the test is recommended. It is suggested that the paper strips removed primarily physically bound extractable P from all soils (approximate 1:1 relationship), with little extraction of amorphous Al and Fe or Ca compounds indicated. A potential general applicability of Fe-Al-oxide-impregnated paper strips to estimate plant-available soil P is suggested.