In the late 80’s early 90’s periodic failure of canola crops were occurring in NSW. Responses to nitrogen were being seen in canola trials but no responses to the addition of sulphur (Sykes and Colton 1990) were occurring. In 1991 the KCL40 soil test was developed and validated in pastures. Canola crops in southern NSW were responding to gypsum (Helen Burns). In 1991 “Canola Check” identified sulphur responses at , Temora, Young and Cowra.(GRDC 1993). In 1992 John Sykes – sulphur in canola. Incitec/NSW Agriculture established joint research trials. In 1993 publications and advice eg “Canola needs sulphur” reported results from field trials. From 1993 onwards the widespread use of sulphur in canola growing systems was occurring. In 1995 research papers were published reporting on NSW Agriculture and Incitec field trials (Good and Pinkerton)
The yield increases from the 1993 and 1993 joint trials were significant. Where canola was following pasture and sites were responsive to sulphur 40% of trials responded to 40kgs/ha/S. Where canola followed cereals only 11% of the sites responded to 40kgs/ha/S
Where severe sulphur deficiency occurs the flower petals are pale yellow to cream and most flowers fail to form pods. Losses of up to 80% of seed yield plus a reduction in seed oil concentration have occurred in central and southern due to S deficiency.
Field trials have shown that S-deficient canola responds to sulphate –S topdressed at the start of stem elongation, giving up to 100% recovery of seed yield and oil concentration. Economic responses to topdressed sulphate-S have been recorded as late as flowering in salvage situations. (Hocking et al)