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Nocardiae were isolated from 15 out of 47 soils using Diagnostic Sensitivity Test Agar supplemented with antibiotics. Up to 7.3 × 10 4 g −1 dry wt. soil were counted, indicating that these bacteria might be more widespread and important than previously thought. Study of randomly selected isolates showed that they formed fragmenting mycelium, contained arabinose, galactose, meso-diaminopimelic acid and nocardomycolic acids. They clustered with Nocardia asteroides markers in a numerical taxonomic analysis.

Ryegrass was grown in 12 soils at 10 and 25°C in a pot trial carried out under controlled climate conditions. Adsorbed sulphate determinations were carried out on the soils both before and after the trial using 2 related methods; 1/2 h extraction with 0.04 M Ca(H2PO4)2 followed by charcoal treatment and reductive distillation and 16 h extraction with 0.04 M Ca(H2PO4)2 followed by reductive distillation with no charcoal pretreatment. Total DM yield and S‐uptake at the two temperatures were correlated with the two measures of adsorbed sulphate employed. Estimates of the apparent net mineralisation of organic S during the trial were also made on the basis of each set of adsorbed sulphate measurements and correlated with ester‐S, C‐bonded S and total organic S levels in the soils and with the mean levels of sulphatase activity and microbial respiration recorded during the trial. Sulphate levels determined by the 1/2 h method were significantly less than those determined by the 16 h method. Although t...