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Blue Bags Grow Better Crops


Application of Sulphur has boosted silage yields by the same 29% over two very different years on medium and clay loam soils at Barthomley in Cheshire.

Grazed grass yields have also been lifted by as much as 19% using the NS True Granular Compound as opposed to straight Nitrogen (N).

In the trials CF SingleTop (27N + 12 SO3), which has both N and Sulphur combined in each granule, was compared directly to 34.5% straight N.

On the silage land, Nitrogen was applied at 210kg N/ha over two cuts from both fertilisers with the Sulphur plots receiving 93kg SO3/ha from the SingleTop.

In 2016, first cut from the straight Nitrogen yielded 4.7t/ha dry matter with the Sulphur treated grass yielding 6.0t/ha. In second cut these were 5.0t/ha dry matter and 6.4 t/ha dry matter, respectively with both results representing an almost 30% lift in production in favour of the SingleTop.

For 2017, these changed to 4.2t/ha dry matter for the N only crop and 5.6t/ha for the combined Nitrogen and Sulphur product in first cut with 3.0t/ha dry matter and 3.7t/ha respectively for second cut. Sulphur delivered a 33% advantage in first cut and a 23% lift in second cut.

Totalling up both cuts shows an average of 8.4t/ha dry matter for the AN crops and 10.9t/ha dry matter for NS treatment over the two years. (see graph 1.)

“Overall, both years showed a 29% boost in grass for silage production representing an average gain of 2.4t/ha dry matter across first and second cuts, which was a very strong and consistent response over the two years,” explains James Holloway, CF Fertilisers Western Regional Manager.”

“This suggests that the deficiency is real and relatively stable in the soils so accurate applications and responses can be calculated.”

It’s a similar situation with the grazing trials, he points out. In these, Nitrogen was applied at 180kg N/ha from both fertilisers over the first four rotations, with the Sulphur plots receiving 80kg SO3/ha from the SingleTop.

Sulphur fertiliser on medium soil

“In 2016 we saw a 14% additional yield response to the Sulphur compound and last year this rose to 19%. So the average response was 16% for both years on the grazing land.

“Total grazing yield lifted from around 6.8t/ha dry matter to 7.9t/ha – a 1.1t/ha improvement.”

Levels of atmospheric Sulphur have fallen considerably in recent decades and much of the country’s grassland is suffering as a result, James Holloway believes

“We only get a maximum of 10kg/ha of Sulphate falling from the sky each year now and in many areas of the UK it is below 5kg/ha. Before the industrial clean-up this was around 70 to 80kg/ha.”

“Unlike blended urea Sulphur product, a high quality compound has both N and S combined in each granule so application is consistent and all the grass in a field gets the correct amount.

“It is this consistency in solving a sulphur-deficiency which delivers the yield responses and this is exactly what we have been seeing in the Cheshire results.

“What is interesting from this trial is the new thinking. It used to be thought that only the lighter soils got the best response from Sulphur but Barthomley is predominantly medium and clay loam so the results suggest, as time goes by, heavier soils are starting to lose their residual organic matter Sulphur and are now becoming deficient.”