• Liquid Nitrogen and Sulphur Fertilisers

Supplying sulphur to your crops helps grow high yielding healthy produce

The importance of sulphur & liquid nitrogen fertiliser

Whilst Nitrogen is a growth promoter, Sulphur works as a growth regulator, effectively balancing the manufacture of sugars and proteins in leaf tissue with the demand from these materials throughout the plant.

Consequently, Sulphur plays a crucial role in maintaining green leaf area, growth rates and delaying senescence. Low Sulphur levels reduce Nitrogen metabolism, leaf expansion and plant development.

The nutrient is very mobile in the soil meaning wet winters and early springs leave low reserves in the soil. Crops need a steady supply throughout rapid growing seasons, so it’s key to apply S each time N is applied in your fertiliser.

Contact OMEX today for further information or to discuss your requirements.

The Benefits of Sulphur in your fertiliser

green leaf area

growth rates

uptake of nitrogen

OMEX Liquid Nitrogen plus Sulphur fertiliser grades:

Nitroflo 28+S

containing nitrogen and a low level (2.5% SO3) of sulphur.

Nitroflo 26+S

containing nitrogen and 5% SO3 sulphur; for top-dressing sulphur responsive crops in the spring during periods of rapid growth and ensuring strong, even growth. The sulphur source is sulphate. The most widely used product in the Nitroflo range.

Nitroflo 24+S

containing nitrogen and a higher level of S (7.5% SO3) than Nitroflo 26+S. The sulphur source is sulphate.

Nitroflo 22+S

containing nitrogen and a higher level of S (10% SO3) than Nitroflo 24+S. The sulphur source is sulphate.

Nitroflo 20+S

containing a higher level of sulphur (12.5% SO3) for deficient areas and crops with a high demand for sulphur, such as oilseed rape. The sulphur source is sulphate.

Nitroflo 15+S

containing an equal amount of nitrogen and sulphur; ideal for first nitrogen application on oilseed rape. The sulphur source is sulphate.

Sulphur fertiliser trials results

A 2019 Nitrogen plus Sulphur fertiliser trial showed:


Sulphur applications can
raise grain yield
by over 1t/ha

A 2017 trial on potatoes using OMEX Suspension fertiliser, with and without Sulphur showed:


Higher number
of marketable tubers


Higher dry matter


Higher number
of marketable yield

A significant improvement
in fry colour

Lower levels of
skin disease, especially
common scab

Supplying Sulphur with OMEX Multiflo

Suspension Ferilisers offer farmers a bespoke nutritional service, meaning the crop receives exactly what it needs to grow. Using the free soil sampling service OMEX provide, you’re able to gain a true understanding of the Sulphur requirements for the season. Multiflo offers tailor made nutrition, and are applied by a contractor service, meaning they’re a useful time management tool.

How much Sulphur to Apply

The continued reduction in sulphur deposition means that many rural areas of the UK currently receive less than around 5 kg/ha of S from the atmosphere. The following recommendation take this into account.

  • Most oilseed rape crops require a minimum 100kg/ha SO3 sulphur. Crops therefore require an application of 75 – 100 kg/ha of SO3.

  • Cereals require approximately 60kg/ha SO3 of sulphur and much of East Anglia and many areas in the North East are at medium risk of sulphur deficiency. Crops in these areas therefore require approximately 50 kg/ha SO3 sulphur.

  • Historically, maize was grown in rotations with often large inputs of manure and slurry, which usually provided sufficient sulphur for the crop.

    With maize being increasingly grown outside livestock areas it is important to consider the sulphur requirement of the crop and an application of 50-75 kg/ha SO3 particularly on light soils is usually required.

  • Most brassica crops have a relatively high requirement for sulphur and adequate levels of sulphur are required for improved taste in a number of vegetable crops.

    Sulphur is also required to ensure efficient nitrogen utilisation in vegetable crops, with deficiency often resulting in reduced nitrogen responses.

    Application of 40-50 kg/ha SO3 is recommended in responsive situations.

  • Sulphur deficiency reduces the yield and quality potential of grassland and is exacerbated by high forage removal rates. Responsive crops require approximately 40 kg/ha SO3 . Top-dressing with Nitroflo 20+S provides immediately available sulphur to supply the crops needs