Pasture responses to superphosphate and elemental sulphur on soils of the West Coast, South Island

Abstract

The effects of applying superphosphate, with or without elemental sulphur (S), to established pasture were measured at 3 sites of varying soil phosphorus (P) status. Regardless of whether background soil P levels were high or low, > 90% of maximum pasture yield was achieved with superphosphate applied at 250 kg/ha (23 kg P/ha). The form and number of applications of S fertiliser affected pasture production, but the rate did not. Under conditions of high S leaching (rainfall 3400 mm/year, soil retention of anions low), the use of elemental S in the spring or applications of superphosphate in September and February gave best S supply. Where conditions were drier (annual rainfall 2000 mm) and soil had better anion retention properties, a single application of superphosphate in the spring appeared to provide a suitable supply of S.