A method capable of wide application to the analysis of plant and faecal materials involving X-ray fluorescence spectrometry for magnesium, aluminium, silicon, phosphorus, sulphur, potassium and calcium is described. Ball milling the material for 10 minutes is sufficient to eliminate particle-size effects in samples diluted 1 + 1 with cellulose when compressed into discs. Inter-element effects are overcome by the use of correction lines and calibration for all elements is carried out with synthetic standards made by incremental addition.

Most of the elements can be determined with coefficients of variation within ±1·0 per cent. at low concentrations. Results covering wide concentration ranges, obtained by X-ray and chemical methods, showed good agreement for a variety of samples, including heather, peat, clover, rye grass, mixed herbage, grain, straw, kale leaf, turnip, hay, silage, oak leaf and draff, thus indicating that almost all samples of vegetable origin can be reliably analysed for these seven elements by the proposed X-ray method.