Field studies with radioactive sulphur-labelled gypsum fertiliser

Abstract

The movement of fertiliser sulphur (S) within the profiles of soils, belonging to the recent and yellow-brown earth soil groups, was investigated by applying ³⁵S-labelled gypsum fertiliser in the spring to several field trials located on these soils. Under similar rainfall conditions, the patterns of fertiliser S movement varied. The main soil properties and processes contributing to this variation were S retention capacity and water-holding capacity. The extent of pasture improvement, as related to soil organic matter status and bulk density, had little effect on fertiliser S movement. The significance of the observed fertiliser S movement is discussed in relation to the fertiliser S requirements of pastures.