Experts agree that sulphur management is vital for optimal crop production

The overwhelming importance of sulphur management in optimal crop production was a key takeaway from NRM and Rothamsted’s recent webinar, “Optimising sulphur nutrition to maximise yield and quality”.

“We all recognise nitrogen, phosphorus, and potassium as the three major nutrients essential in helping our crops get everything they need to thrive. However, to my mind, sulphur is the second most important nutrient you should be considering when it comes to fertilisers and crop nutrition—just behind the big one, nitrogen,” said Professor Steve McGrath, Discovery Leader at Rothamsted Research. “Our research trials have demonstrated that sulphur deficiency impairs plant metabolism, reduces protein synthesis, and suppresses nitrate uptake, and therefore nitrogen utilisation efficiency. This means that expensive nitrogen is lost due to sulphur deficiency, and most likely a lot of other key nutrients because of poor root growth.”

According to Professor McGrath, routine sulphur fertiliser applications are needed to maintain crop yield and quality in the UK. However, as sulphur has minimal residual effect, it’s best to apply every year. He also noted that, while organic manures contain sulphur, they often don’t provide enough available sulphur to meet crop requirements. Sulphate is the central factor in ensuring optimal levels, as this is the form of sulphur that is available for crops to take up. Plants cannot take up elemental sulphur, as it needs to be oxidised in the soil to be available to the crop.

These findings were reinforced by NRM’s data, which highlights the importance of regular soil analysis to ensure that nutrient levels are sufficient to support crop performance.

“When analysing our data, we were truly surprised at how critical the situation has become around sulphur in the UK,” said Dr Sajjad Awan, Soil & Crop Nutrition Agronomist at NRM. “For example, around 15% of the 7,000 soil samples we received in the lab from 2021 to 2023 were found to have far less available sulphur than what is required for optimal crop yield. This was supported by our plant tissue data from 2023, where we saw that higher nitrogen concentrations in the samples did not result in higher yields compared with 2022, as one might expect.

“What’s the likely reason? It turns out that deficient sulphur levels in these plant tissue samples may have stifled yield. So, simply applying nitrogen may not always be the answer—sometimes, it’s a matter of making sure the sulphur is there to help make sure nitrogen is efficiently used by the crop.”

The webinar, held on Wednesday 19^th February 2025, attracted attendees from across the agricultural industry. It featured engaging discussions, an interactive Q&A session, and valuable expert recommendations.

“It’s important to remember that analysis is crucial in diagnosing issues accurately for insightful management decisions,” Dr Awan concluded. “Sulphur has become deficient across the board, and I’d say grain analysis is a must to help you adjust plans for the following season as a ‘post-mortem’ of your nutrient management plan.”

Dr Awan also highlighted the role of climate variability in nutrient management: “Some years we have very dry periods, where applied fertiliser isn’t effectively incorporated into the soil, while in others—like recently—wet and cold Springs compromise nutrient availability. My advice is to analyse all year round to make sure your crops are where they should be, so you can make adjustments quickly as needed.”

Key takeaways from the webinar include:

• Sulphur deficiency in UK soils has become widespread
• Sulphur is the second most critical nutrient after nitrogen for crop production
• Different crops have different sulphur requirements, and need to be considered individual for optimal growth
• Climate variability requires a more adaptive approach to sulphur management
• Year-round soil, tissue, and grain analysis is vital in tracking sulphur levels, adjusting fertiliser plans effectively, and better managing crop productivity.

For those who missed the live session, you can watch the full webinar recording here.

Stay tuned for more events and insights, and thank you to all who attended and contributed to this successful webinar!