Yield and economic response to nitrogen and phosphorus fertilizers on a low-phosphorus soil of the Darling Downs, Queensland

Abstract

While maximum wheat yields appear to be obtained with rates of up to 3·6 cwt superphosphate and 2 cwt urea per acre (37 lb P and 103 lb N respectively) on the Mywybilla series of Darling Downs black earths, economical rates were 1 cwt superphosphate and t cwt urea per acre (11 lb P and 26 lb N respectively). It is recommended that both fertilizers be applied for fertility maintenance. Highly significant responses in grain protein occurred but these were not sufficient to raise the grain quality status on the Australian price structure. Increased stubble may be expected with the use of fertilizer.