| Arable
Trials suggest sulphur shortages
extending across most soil types
An increasing area of UK grassland could be developing Sulphur deficiencies
sufficient enough to affect yields and quality a new series of nationwide trials
suggest.
hilst Sulphur issues have been
prevalent on lighter soils for
many years, heavier soils are
now starting to show signs of
less than optimum levels, says
independent grassland
specialist Dr. George Fisher.
“The amount of Sulphur falling from the sky
has diminished significantly in the last few
decades with the reduction of coal-fired power
stations and the general clean-up that industry
has achieved.
“At its height this was around 70-80kg
Sulphate/ha each year but it’s now around
10kg/ha maximum and in some areas of the
country it’s no more than 5kg/ha.”
Such levels are simply insufficient to
replenish that taken out by productive
grassland with performance declining as a
result, he says.
In trials on medium loam soils in Cheshire
over the last two years, CF SingleTop Sulphur
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16 | Farming Monthly | March 2018
containing fertiliser (27N + 12SO3) has been
shown to produce an average 10.9t/ha dry
matter yield over first and second cut silage as
opposed to 8.4t/ha for crops receiving N only –
a 29% improvement.
On the same reseeded pasture used for
grazing, SingleTop produced a 14% additional
yield response compared to straight Nitrogen
and last year this rose to 19%.
Silage trials in Devon and Cheshire on heavy
clay loams have produced responses to
Sulphur of +10% and +6%, and although the
results are more variable on heavier ground,
they do show the impact of Sulphur is no
longer limited to just lighter soils, he says.
“In fact, on the Devon site, when Sulphur
and Phosphorus were added together, yields
increased from 4.2t DM/ha from the straight
Nitrogen to 5.2t DM/ha – a 24% lift.
“At the other end of the country, indications
from SRUC trials in Aberdeen suggest an
average 10% lift in yields for first cut silage are
possible with using Sulphur on heavier soils.”
According to CF Fertilisers’ Northern
Regional Manager Mark Garrett where slurry is
used for both first and second cut on soils with
adequate P and K, the main requirement is for
NS compounds like SingleTop.
If the P index is high but the K index low,
particularly if it’s on a lighter soil type,
producers should consider using SingleTop
(27N + 12SO3) in spring then KayNitro Sulphur
(25-0-13 +7SO3) in the summer, he says.
“NKS products are particularly beneficial
where P index is high and soil Potash levels
need to be maintained.
“MultiCut Sulphur (23-4-13 + 7SO3) can be
used as an all season high Nitrogen/high
potash product ideal for multiple cuts of grass
silage with reduced Phosphate content to help
maintain soil P and K status.”
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