A comparative field evaluation of some potential sulphur fertiliser materials

Abstract The escalating cost of superphosphate, the traditional phosphorus (P) and sulphur (S) fertiliser in New Zealand, has led to increased awareness of high analysis P and S fertilisers. With S, interest has centred on elemental S (S°), but to be effective, S°fertilisers must be readily oxidised to supply sulphate-S (SO4-S) at a rate which satisfies plant requirements. This rate is largely dependent on particle size. Experimental batches of alternative S°fertilisers, with future commercial possibilities for New Zealand pastures, were assessed over three seasons, from 1982 to 1985, in a cool temperate environment. These products included granulated ground S°;mixtures of molten S° and sodium (Na) bentonite; a mixture of S° and anhydrous calcium sulphate; imported sulphur prills; imported ground gypsum; and S° particles in five size ranges. Their effectiveness was compared by reference to a nil S control treatment and to five rates of S applied as molten mixed sulphur superphosphate (MMSS). The prime ind...