Lack of sulphur linked to patches
Lack of sulphur linked to patches
By John Burns
SULPHUR deficiency is being blamed for an outbreak of tabletop-sized circular patches of stunted wheat and barley plants in Devon and Cornwall.
The patches, which look like BYDV infections, contain plants 15cm (6in) shorter than the surrounding crop, says Bill Butler, ADAS arable area consultant.
"We first saw them about three years ago and we are now seeing them more and more, across all soil types and farming systems."
Take-all has been confirmed in the patches and the plants have been shown to be deficient in sulphur. "You could argue that the plants were sulphur-deficient because take-all damage to their roots had prevented adequate uptake of sulphur," says Mr Butler. "But we have circumstantial evidence that the take-all follows the sulphur deficiency.
"Clients who now apply sulphur as a routine, usually by using ammonium sulphate as their nitrogen source, have not had this trouble. Another client who was using ammonium sulphate to supply sulphur as well as nitrogen ran out and had to do part of a field with ammonium nitrate. Those characteristic stunted patches appeared in the part of the field that did not receive the ammonium sulphate."
Mr Butler now thinks there is a major shortage of sulphur in Devon and Cornwall, even where FYM is used regularly. "And I am convinced there is a connection between sulphur deficiency and take-all.
"Next year I will be advising all my clients to use ammonium sulphate."
ADAS plant pathologist Bill Clarke knows of nothing in scientific literature to suggest any link between sulphur deficiency and take-all, but admits it is possible.
"There is just one thing to remember about using ammonium sulphate – some of it is an industrial by-product and can be difficult to spread accurately." *
SULPHUR DEFICIENCY
• BYDV-like patches.
• Take-all confirmed.
• S shortage to blame.
• Use S fertiliser to avoid.