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Although over 40% of excretal S is returned to intensively sheep ‐grazed pastures as faecal S, limited information is available on faecal S fractions, their water solubility and temporal distribution. This study reports results obtained from sheep faeces returned to grazed pastures which have received long‐term annual sulphate applications for 15–20 years. Five freshly‐voided sheep faecal samples ( 80%) faecal S fraction, regardless of faecal total S content or the time of year faecal samples were deposited. Faecal ester SO4 2‐ and inorganic _SO4 2‐fractions accounted for 3.3–7.1% and 0.1–1...

A laboratory study was conducted to investigate whether the Zn‐Na acetate solution, used for trapping H2S in the Johnson‐Nishita method (1952), could be used to quantitatively determine 35S and 32S in the same trapping solution, as the Zn‐Na acetate solution allows more sensitive S determination using methylene blue than does the bismuth sulphide colour development of H2S trapped in NaOH solution. Results obtained using the Zn‐Na acetate solution were variable compared with those obtained from the normal procedure of using NaOH as the H2S trapping solution, indicating that the Zn‐Na acetate solution was unsuitable, probably because of the rapid transformation of H2S to water‐insoluble ZnS. The applicability of methylene blue development for H2S trapped in NaOH solution was also investigated. Results showed that 32S could be determined quantitatively provided methylene blue colour development was conducted less than 30 minutes after the removal of H2S‐trapping NaOH solution from the Johnson‐Nishit...