RESPONSE OF STYLOSANTHES-HAMATA CV VERANO AND NATIVE PASTURES TO FERTILIZERS ON 2 LIGHT-TEXTURED SOILS IN NORTH-WEST QUEENSLAND

The effects on yield and quality of applying fertilisers to Stylosanth es hamata cv. Verano (Caribbean stylo) and to native pastures were mea sured in 3 field experiments on a grey kandosol and a brown sodosol su pporting Melaleuca woodlands in north-west Queensland. Phosphorus appl ication at a rate of 30 kg/ha P increased Verano yield annually in the first 4 years. The maximum yield achieved was > 6000 kg/ha on a grey kandosol in the second year. Eighty percent of maximum legume yield wa s achieved with acid-extractable soil P levels of 8 mg/kg. There was a lso a yield response to sulfur and zinc at establishment, but not in s ubsequent years. The nutrient concentration responses of Verano to fer tilisers are reported. Dry matter yield of native pasture was increase d by both nitrogen (from 2050-3630 kg/ha) and superphosphate (to 3080 kg/ha) fertiliser in the first year, but not in the second growing sea son when rainfall was low. Concentrations of P and S in the native pas ture were increased by super-phosphate (from 0.03% and 0.07% to 0.12% and 0.10% respectively) in the first season. Productive Verano pasture s with nutrient concentrations adequate for animal production can be g rown on these infertile soils by applying single superphosphate alone. Most commercial pastures are not adequately fertilised and an applica tion of 30 kg/ha P every 5 years is suggested.