THE USE OF IRON OXIDE-IMPREGNATED FILTER-PAPER FOR THE EXTRACTION OF AVAILABLE PHOSPHORUS FROM TAIWAN SOILS

Procedures were established for the preparation of iron oxide-impregnated filter paper and for its use in the determination of plant-available soil phosphorus. The amounts of phosphate extracted by the procedure from 39 soils of the major agricultural areas of Taiwan were well correlated with those extracted by young wheat seedlings or other chemical extractants commonly in use for soil testing. It was shown that the iron oxide-impregnated filter paper method is applicable to a wide range of soils in Taiwan and that the results are comparable with those obtained with the anion-exchange resin and Olsen methods.