Sulphur is often overlooked when it comes to grassland and especially silage, the focus so often being on Nitrogen, Phosphorus and Potassium. However Sulphur is present in all crops and plays an essential role in plant metabolism and the formation of plant protein amino acids and enzymes.
Until relatively recently, Sulphur deficiency wasn’t seen as an issue. Depositions of atmospheric sulphur as sulphur dioxide from the burning of fossil fuels guaranteed a plentiful and free supply for UK farmers. But tightening legislation saw deposition greatly reduce, so much so that deposits have declined by 94% since 1970. Government figures suggest that 6.8kg/ha of sulphur are now deposited annually on UK grassland and bearing in mind that an average silage crop requires 40kgS03/ha/cut, sulphur deficiency in grassland is a very real but not always apparent issue.