A Simplified Determination of Reductant‐Soluble Phosphate in Soil Phosphate Fractionation Schemes

Abstract

Abstract A simplified and more rapid procedure for the determination of reductant‐soluble phosphorus (P) was developed by a modification of the Murphy and Riley (1962) ascorbic acid method. The procedure which eliminated the interference of sodium dithionite by air‐oxidation and that of sodium citrate by addition of ammonium molybdate, was suitable for the determination of 0.1 to 0.7 µg P/ml in the presence of up to 3000 µg Fe/ml and 4.0 µg Si/ml.