Nitrogen and sulphur requirements of some soils of the Wyreema-Cambooya district, in the eastern Darling Downs of Queensland.

Abstract

A glasshouse experiment and field trials were used to assess the requirements for nitrogen and sulphur and, to a lesser extent, potassium for some soils of the Wyreema-Cambooya area of the eastern Darling Downs of Queensland. Nitrogen deficiency was found in a number of soils in the area and a response can be expected to annual applications of nitrogen on most commercial crops. Potassium fertilisers appear not to be needed but low soil P analyses and a response to phosphorus indicate the need for phosphorus fertiliser applications. Sulphur may become limiting for cereal growth on some soils of the area. The responses at present are probably masked by adequate sulphur mineralisation during periods of fallow. Growers could apply single superphosphate as a source of phosphorus to annual crops. At the rate of 10 kg/ha P this would also supply
11 kg/ha S, to correct marginal sulphur levels.