Wheat yield responses to various phosphate fertilizers in South Australia

Abstract

A number of phosphate fertilizers were tested as a source of phosphorus for wheat during three seasons (1967-1969) in the cereal growing areas of South Australia. The fertilizers were standard superphosphate, double superphosphate, calcium phosphate, two forms of calcined phosphate, a mixture of calcined phosphate with superphosphate, and untreated rock phosphate. Nine experiments were sown on a range of soils (pH 6.2 8.4) during the three years.At equivalent rates of total phosphorus, the water-soluble phosphates (superphosphate, double superphosphate) and the readily hydrolysed calcium pyrophosphate gave similar responses in all experiments. Water insoluble calcined and rock phosphates gave lower yields than superphosphate and, in most cases, the yields were not significantly greater than with no fertilizer.Uptake of phosphorus in the grain paralleled the grain yield differences between the fertilizers.