Winter Canola Response to Sulfur Fertilization.

Historically agronomic crops do not respond on most Ohio soils to supplemental S. Winter canola is known to have a larger demand for S than other crops. Since winter canola is a relatively new crop in Ohio little is known about the benefits of supplemental S. To test the hypothesis that canola yields may be increased with supplemental S, plots were established on the OARDC Northwest Research Station near Custar and/or at the North Central Research Station near Fremont in 2003 - 2004, 2006 - 2008, 2010, and 2012. Each plot received 20 – 30 lb acre^-1 of fall N prior to planting and 100 lb acre^-1 of spring N prior to bolting. Sulfur was applied the same time as spring N at two rates (20 and 40 lb acre^-1). Sulfur sources were either ammonium sulfate (AMS) or calcium sulfate. Nitrogen was applied as urea. Credit was given for the N in AMS and balanced with urea to achieve 100 lb N acre^-1. Leaves were collected at early pod development to determine S content. Experimental design was a completely randomized block with four replications. Statistical analysis was a simple ANOVA. Eight out of 10 site years showed no yield increase from sulfur. Two site years at the Fremont location showed a yield increase at the 40 lb acre^-1 rate. However, the yield increase may have been a result of more stabilized N from the ammonium in the AMS rather than S. Results from this study would suggest that winter canola grown on most Ohio soils would have little yield response to supplemental S.