Why sulphur matters for Nitrogen Use Efficiency

Sulphur plays a central role in how crops use nitrogen. Where sulphur supply is limited, nitrogen cannot be fully converted into yield and protein.

Sulphur deficiency is still seen on many UK soils, particularly lighter land and where atmospheric deposition is low.

The role of sulphur in nitrogen use

Sulphur is essential for amino acid formation, including cysteine and methionine, which are required for protein synthesis.

Where sulphur is insufficient, nitrogen uptake can continue but conversion into protein is reduced. This leads to lower yield potential, reduced grain quality and poorer nitrogen efficiency.

Evidence from Agrii trials

Agrii trials with sulphur-containing fertilisers such as Polysulphate have demonstrated that improving sulphur supply can support crop performance while maintaining output at lower nitrogen rates.

This reflects improved efficiency of nitrogen use within the crop where sulphur is not limiting.

Recognising sulphur deficiency

• Pale younger leaves
• Uneven crop growth
• Reduced biomass and tillering
  
  

What this means in practice

Where sulphur is adequately supplied:

• Nitrogen is converted more efficiently into yield
• Grain protein targets are easier to achieve
• Response to applied nitrogen becomes more consistent

In contrast, where sulphur is limiting, increasing nitrogen rates alone will not deliver the expected response.

Getting sulphur strategy right

• Apply sulphur early alongside first nitrogen applications
• Match rates to crop demand
• Ensure a reliable supply through appropriate fertiliser choice
  
  

In practice on farm

Sulphur should be treated as a standard component of nitrogen programmes. Correcting sulphur supply is often one of the most straightforward ways to improve Nitrogen Use Efficiency on farm.