A sodium hydroxide fusion method for the determination of total phosphate in soils

Abstract Total phosphate in soils can be determined at low cost using a sodium hydroxide decomposition technique followed by spectro‐photometric measurement in solution. The fusion, in nickel crucibles, is more rapid and takes place at a much lower temperature than the conventional fusion with sodium carbonate. Analyses compare well with published results for standard rocks and with analyses for a range of Scottish soils obtained by X‐ray fluorescence spectroscopy and by sodium carbonate fusion.