The Use of Polyacrylamide to Replace Carbon in the Determination Of‘olsen's’extractable Phosphate in Soil

Summary The addition of 2.5 mg/l of polyacrylamide to 0.5M NaHCO 3 used as an extractant for ‘available’ phosphate overcame most of the analytical difficulties associated with the use of activated carbon which was recommended in the original procedure of Olsen et al. (1954). No significant differences in the amount of P extracted were found between polyacrylamide and carbon and with the former, technical problems were greatly reduced. Consequently, the modification of the original method to incorporate polyacrylamide has been adopted in the Agricultural Development and Advisory Service of the Ministry of Agriculture, Fisheries, and Food as a standard method for the determination of available phosphate in soils.