Comparison of the long-term effects of different sulphur fertilisers on legume pasture production on a toposequence of North Otago soils, New Zealand

Abstract Rates of sulphur (S) fertiliser for longterm legume pasture (a mixture of lucerne and red, white, and alsike clovers) production were measured for three forms of S fertiliser at each of four sites (two altitudes (450 and 800 m) and two aspects (sunny and shady)), on yellow-grey earth soils in the Waitaki Basin, under a cutting and removal management. The experiment covered a 3-year period (4–6 years post-establishment). Superphosphate and molten mixed S superphosphate extra (MMSS) (27% S) proved more effective forms of S fertiliser than screened agricultural elemental sulphur (S°). Pasture production reached c. 90% maximum with superphosphate and MMSS fertilisers applied at 50 kg S/ha biennially whereas at least 100 kg S/ha of screened agricultural S° was required biennially for similar production. In addition, the superphosphate fertiliser applied at sufficient quantities to maintain this level of pasture production (described as maintenance fertiliser S requirements), also supplied sufficient p...