Skip to the content

How important is Sulphur for the health of soil?

Sulphur element

After N,P,K, sulphur is the fourth most important element for crop nutrition.

When the UK burnt coal, we rarely suffered from a serious deficiency, but now with clean air, we must add sulphur. Most fertilisers applied today contain some sulphur as sulphates, such as ammonium sulphate and sulphates of metals added as trace elements. But, as they are water soluble, they rapidly wash away with rain. This means most land in the UK is still below the required sulphur level for optimum growth.

Why sulphur is key to plant growth

When a plant is deficient in sulphur it shows a yellow leaf colour due to the low chlorophyll production. Its overall development will be impacted and, when discovered, it may already be too late for treatment.

Some treatments are ineffective

Traditionally, in many other countries, farmers have applied sulphur + bentonite mixtures, usually 90%+10%, and the bentonite holds moisture, helping the oxidation of the sulphur to sulphate. The typical application rate is 100 to 150 kg per hectare. Though cheap, its big disadvantage is that it takes about three months to oxidise and release sulphur to the crop, so planning in advance is needed. Why does it take so long to become active? Because the sulphur particles at 75 microns are so big.

New developments 

This year, for the first time in the UK, Hockley Agro will offer the patented sulphur product now leading the US and other world markets. It offers a sulphur granule where the sulphur is micronised to typical 2-4 microns and formulated with dispersant, resulting in soil bacteria that starts oxidisation from day one, feeding the crop continuously for 60 days and beyond. This product is very efficient, being applied at only 10 to 15 kg per hectare. Both large granules for broadcast application and micro granules for sprayer application are available. It can be tank-mixed with liquid fertiliser.

Why does this product work so fast and efficiently? Simply because one kilo of sulphur at 2 microns particle size compared to one kilo at 75 microns has greater than 50,000 times more particles with an increase in surface area of some 37 times.

Key advantages are:

  • Apply when needed - starts to work immediately
  • Disperses but does not wash away with rain
  • Provides a continuous supply of sulphur for 60 to 90 days
  • Broadcast or spray application (can tank mix)
  • Competitive pricing
  • Convenient 15kg bags, palletised


For more information or a sample please get in touch at