Field studies with radioactive sulphur‐labelled gypsum fertiliser

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 35 S‐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.