Feasibility of a New Granular Rapid Release Elemental S Fertilizer in Preventing S Deficiency of Canola in S-deficient Soils

S. S. Malhi

Department of Renewable Resources, Room 751, General Services Building, University of Alberta, Edmonton, Alberta, Canada T6G 2E3;

Our previous research indicated that granular elemental S (ES) fertilizers were not effective in increasing seed yield of canola, because of slow dispersion of ES particles and their subsequent oxidation to sulphate-S. A 3-yr (2011-2013) field experiment was conducted to determine relative effectiveness of a new rapid release elemental S (RRES – called Vitasul) and potassium sulphate fertilizers (applied at 20 kg S ha-1) with five application times and placement combinations (broadcast in autumn/incorporated in spring, broadcast/incorporated in spring/pre-tillage, broadcast in spring/pre-emergence, sidebanded and seedrow-placed in spring, plus a zero-S control) on seed yield, oil concentration, N and S uptake, partial factor productivity (PFP – kg seed kg-1 applied N ha-1 – blanket application of 120 kg N ha-1), S use efficiency (SUE - increase in kg seed kg-1 applied S ha-1) and percent recovery of applied S (%) on canola on a S-deficient soil at Star City, Saskatchewan. There was a significant response of seed yield to applied S in all 3 years. Seed yield increased considerably with all sulphate-S treatments compared to the zero-S control, although yields differed slightly among treatments. Seed yield also increased significantly with all RRES treatments, but increases were greater with autumn than spring applied RRES in many cases. Oil concentration in seed increased only with sulphate-S fertilizer in 2011, and it increased with both S sources in 2012 and 2013. The response trends of N uptake and PFP were usually similar to seed yield for both S sources, but S uptake, SUE and % recovery of applied S were lower with RRES than sulphate-S in many/most cases. In conclusion, our findings suggested the potential of spring broadcast pre-emergence or autumn broadcast RRES in preventing S deficiency, although seed yields were still slightly lower than the ideal highest yielding spring broadcast/incorporated sulphate-S treatment.

Mode of Presentation: Either Oral or Poster, whatever you decide (I prefer Oral)