This project evaluated the response of canola to applied fertilizer sulphur. Atmospheric sulphur dioxide deposition (acid rain) has steadily declined by over 50% during the past 20 years. Environment Canada estimates deposits have decreased from 25-30 kg/ha/yr. in 1990 to 9-11 kg/ha/yr. by 2010. Many farmers have increased their use of sulphur in response to more frequent reports of sulphur deficiency symptoms appearing in canola, winter wheat and alfalfa. This project evaluated the response to sulphur in canola.
Canola requires more than 20 lbs. S/ac (23 lbs. S/tonne); alfalfa requires about 25 lbsS/ac (5 lbsS/ton). Sulphur is not mobile in plants so a continuous supply is required. Most of the sulphur in soil is associated with organic matter. Availability is highly variable from year to year and site to site and is subject to leaching as experienced with nitrogen. This project was built on previous best management practices trials to evaluate the yield and economic return to fertilizer sulphur applications.