S vital role emerging
IN six years of Arable Research Centre organic trials testing a range of permitted products to try to improve grain yield and/or quality, none gave any significant responses until last year, said director Mike Carver.
Then, reflecting the general trend in conventional farming, two formulations of sulphur produced useful yield responses in a field with a known S deficiency.
As atmospheric deposits from the air have declined, responses to added sulphur in conventional crops have been dramatic, said Dr Carver. In 2000 the addition of 40kg/ha of S nearly doubled oilseed rape yields. "It is a sobering thought. Once sulphur deficiency hits an area its not going to go away. Sulphur has become part of conventional agriculture. Is it now going to have to become part of organic cropping?" *