A modified resin exchange method for measurement of available phosphate in soils derived from volcanic ash

Abstract

An experimental method to determine available phosphate in soils using anion exchange resin as an extractant has been described (3, 5). However, when this method is applied to volcanic ash-derived soils, some problems arise. First of all, the original method is based on the phosphate retention capacity of an anion exchange resin which is brought into contact with the soil and then separated from it by mechanical means (screening). This separation presuposes that the resin particles are of a greater size than the soil particles. Therefore the soil has first to be airdried, ground and sifted. Besides, when using the above technique many resin particles are broken during shaking which may prevent their recovery.