Scots go elemental to combat shortage
ELEMENTAL sulphur rather than blended, granular product is making a return in the north of Scotland, as growers struggle to combat severe deficiency problems.
"The return to elemental sulphur sees us going full circle," says Doug Limburn of Robertson Crop Services, which has about 300 farmer customers from Inverness to Aberdeen.
"When sulphur deficiency and its effect on nitrogen uptake was first recognised in rape, the Macauley Institute recommended applying 20kg of Thiovit which was 80% elemental sulphur," Mr Limburn recalls.
That helped prevent deficiency, particularly in winter rape which suffered badly, often turning white because the lack of sulphur made nitrogen unavailable to the crop.
"But then there was the move to blend sulphur into granular fertilisers at a rate of 2 to 4%. That was fine, but there were problems because the sulphur was in the soluble sulphate form and it leached from the soil during the winter.
"Top dressings were needed later in the season and we began to think again about the benefits of elemental sulphur, where oxidisation to sulphate occurs as the soil temperature rises.
"It gives a slower release but one which is maintained throughout the growing season," says Mr Limburn.
The spreadable granule being tried this year is Stefes Tiger 90, containing 90% elemental sulphur plus 10% lignite clay. The latter expands to spread sulphur across the soil surface.
"We heard about the new product last autumn, but many farmers had already bought sulphur-containing fertilisers in advance. About 10 farmer clients are using it and we will be monitoring the effects throughout the season," he says.