Sulphur containing fertiliser grades are too often dismissed as they command a small premium over the same grade without sulphur. However, the evidence is such that sulphur is now recommended by all the independent farm advisory bodies in the UK, including the AHDB in England, IBERS in Wales, and the SRUC in Scotland and AFBI in Northern Ireland.
We need sulphur applications now because in the past it came in sufficient quantities in our rain. Now, annually the rain provides less than 5kg SO3/ha.
Plain and simply sulphur helps nitrogen work better, and when nitrogen works better it improves grass growth rates but also the composition of the grass. For example, if we grow 1,000 kg more dry matter per ha just by using a fertiliser with sulphur, then this has had the effect of improving nitrogen use efficiency. There is an extra 20 kg of nitrogen removed in this 1,000 kg of dry matter which means there is less nitrate in the soil available for leaching which could potentially end up in our rivers. This is a win-win for the farmer and the environment.
Valuing the cost effectiveness of using sulphur this season
Yara commissioned the Agri-Food and Biosciences Institute (AFBI) in Northern Ireland last year (2017) to look at the role of sulphur on grassland. AFBI carried out these field trials at two different sites in Northern Ireland.
The soils at Hillsborough and Loughgall were characterised as a clay loam and a sandy clay loam respectively.
The overall dry matter (DM) yield was achieved over 6 cuts. A total nitrogen rate of 204 kg/ha was used for each treatment, with the YaraBela Nutri Booster supplying a total of 41 kg SO3/ha of sulphur.
Sulphur applications resulted in an extra 750 kg DM/ha
At the Hillsborough trial site the treatment including sulphur yielded 11.3 tonnes compared to 10.9 tonnes dry matter per ha without sulphur
At the Loughgall trial site the treatment including sulphur yielded an extra 1.1 tonnes dry matter per ha
What is this extra 750 kg dry matter worth?
The cost of growing this extra 750kg of dry matter was £15 per ha, based on the value of YaraBela CAN and YaraBela Nutri Booster.
Comparing the value of the extra dry matter to feed wheat @ £138/tonne and Hi-Pro Soya @ £305/tonne, with a grazing utilisation of 85% then this 750 kg of DM is worth £113.
A very healthy £7 return for every £1 spent on sulphur.