Signs of a shortfall in Hampshire…
POTENTIAL sulphur deficiency has been identified in cereals grown on light chalk soils in Hants. The findings follow tests carried out on grain samples taken from stores this winter.
Nearly two-thirds of the 25 samples had a total S content below the 0.12% threshold, says Seumas Foster, a member of the Association of Independent Agronomists, near Basingstoke.
Most of those containing adequate S levels were from farms already using sulphur-containing nitrogen fertiliser or sprays, he adds.
"Although its not possible to draw any scientific conclusions from a small survey, it seems crops are starting to run short of sulphur in this area."
Further tests show that the nitrogen to sulphur ratio, an indication of sulphur supply, is also low. All but four samples were below the 17:1 threshold.
As expected, lighter soils appeared to be at most risk, notably around Winchester. But no crop showed signs of sulphur deficiency in the field, says Mr Foster. "With oilseed rape you can spot the symptoms early and correct potential yield loss. In cereals, the symptoms are not expressed so well. Crops may not be reaching their full potential."
He urges growers to carry out a risk assessment. "Those who are not using sulphur should think about it very seriously. Take into account soil type, rainfall, cropping, manure application and sulphur deposition."
Mr Foster will take tissue samples on clients farms this season to assess the problem further, and will test more grain samples this harvest. "I will also seriously consider using NS fertilisers next spring. I think we are getting to the point in this area where sulphur is a routine treatment."
• Local trials identified risk.
• Grain and tissue tests of crops confirmed shortage.
• Winter cereals treated with solid compound in spring.
• Cost – £3.30/ha (£1.35/acre).
• Spring barley and grass
likely to be treated soon.