Effectiveness of an elemental sulfur fertilizer in an oilseed‐cereal‐legume rotation on the Canadian prairies

Abstract

AbstractAdequate sulfur (S) nutrition is critical for sustaining yields in crop rotation systems. Because of slow oxidation of elemental S (S°), research on S° fertilizers has emphasized improving the short‐term availability, while the long‐term effects of S° have been overlooked. The effectiveness of a dispersible granule S° fertilizer (SF: Sulfer95), consisting of S° particles smaller than any S° fertilizer reported in literature (< 44 μm in diameter), was compared to gypsum (CS: CaSO4) and ammonium sulfate [AS: (NH4)2SO4] in a three‐year experiment (1997—1999) on a moderately S deficient Black Chernozem soil (Typic Cryoboroll). The three S fertilizers were applied to canola (Brassica rapa L.) at 20, 40, and 80 kg S ha‐1, supplemented with corresponding rates of nitrogen (N) fertilizer in the first year. The control treatment (CT) received N only. Barley (Hordeum vulgare L.) and peas (Pisum sativum L.) were grown in the second and third years to test the availability of residual S. Although the yield of canola in SF fertilized treatments was only slightly higher than in CT, available S provided by SF produced a higher physiological S efficiency (PSE). Superior yields with residual SF were obtained in the second and third years by barley and peas at the rate of 80 kg S ha‐1 applied in the first year, indicating that slow oxidation of SF was beneficial to the crops subsequently grown. Over three years, the total crop S uptake was 21, 4.0, and 15% higher with SF than with CT, CS, and AS, respectively.