We all know that there is less Sulphur being released into the atmosphere and that’s a good thing for the future. It does mean though that crops need to receive more Sulphur applied by either FYM, slurry or inorganic fertilisers.
Sulphur is available from the soil, but the amount will depend on the soil type. Organic soils have high levels of sulphur, whereas light soils tend to have lower levels due to the Sulphur being leached out. The level of soil available Sulphur can vary month on month depending on rainfall and temperature.
Sulphur is used by the plant to support nitrogen and thus affects protein production. Thus, ensuring sufficient sulphur in grass will help to improve the level of protein in the grazing and silage crops. Deficiency shows up similar to Nitrogen deficiency except the yellowing of the leaves in the young leaves and not the older leaves.
In terms of application levels, the amount varies depending on soil type and crop. Silage fields require more than grazing fields and amounts of inorganic Sulphur needed can be reduced if FYM or slurry is applied. In order to establish how much Sulphur to apply the guidance in the new RB209 should be followed. Slurry has higher levels of available Sulphur when compared to FYM, thus should be used during the cutting and grazing seasons, whereas FYM should be applied in the previous autumn to allow Sulphur to be released to the crop.
If your silage analysis is coming back low in protein with P, K and pH in balance, low sulphur could be a reason, especially on lighter soils.
To draw up a fertiliser plan incorporating sulphur, contact Phil Cooper at firstname.lastname@example.org or any of our FACTS qualified consultants in your local FCG office.