Crop response to elemental sulfur fertilizers in central Alberta

Abstract

Sulfur deficiency has become a widespread limitation to crop production in western Canada. A variety of S sources are commercially available to alleviate these deficiencies but not all are equally effective. Three elemental S products (a finely-divided suspension and two elemental S + bentonite) and ammonium sulfate were compared over a 3-yr period in central Alberta. These products were applied to barley and canola at various rates (0–120 kg S ha −1 ) in a factorial arrangement with various supplemental rates of sulfate-S (0–40 kg ha −1 ) in two experiments Fertilizers affording effective and reliable alleviation of S deficiency in the year of application included sulfate forms and finely-divided elemental S products that can be readily mixed into the soil. The residual benefits of the various fertilizer products examined appeared to be comparable despite large differences in short-term availability. The absence of appreciable residual advantage of slow-release elemental S products was attributed to the short duration of S assimilation by canola and barley and the susceptibility to leaching of S oxidized after that period. Key words: Barley, canola, residual, rotation, S fertilizer, uptake, yield