The effects of sheep faeces on soil solution composition

To elucidate changes occurring in soil solution under sheep faeces we collected faeces from sheep grazing on an improved podzol in Scotland in summer and re-applied it (150 g of fresh weight) to patches, each with an area of 0.018 m². Faeces and/or intact soil cores (0–50 mm deep) from underneath the patches were sampled at intervals up to 224 days and nutrients measured in the soil solution isolated by centrifugation. The treatment with faeces increased the soil solution concentrations of P, N, dissolved organic carbon (DOC), Ca, Mg and K. The greatest increases occurred at day 56 for P, Ca, Mg and K, day 84 for N, and day 112 for DOC. Most of the P in the faeces applied to the soil was in inorganic form, but organic P made a substantial proportion (nearly 50%) of the P in soil solution at the time of maximum effect. The faecal residue became indistinguishable from the soil between 84 and 112 days following periods of persistent rainfall. The data provides a new insight into the effects of sheep faeces on soil solution composition unperturbed by chemical extraction and a contrast with the effects of sheep urine on soil solution composition.Section Editor: N.J. Barrow