Are your soil sulphur levels low following last year’s extreme wet conditions?
NRM
Agriculture
Understanding the mobility of nutrients in soil is key to effective nutrient management. Some nutrients, like sulphur and nitrogen, are highly mobile, making them more susceptible to leaching. This is seen particularly lower down the soil profile, where shallow, restricted, or young roots are less able to access nutrients.
This issue has come into sharp focus following last year’s extreme wet conditions, which significantly impacted nutrient availability and plant health, including soil sulphur levels.
Want to learn more about sulphur and how can we make impactful changes for optimal crop production using key data insights? We held a webinar on Wednesday 19th February hosted by experts from NRM and Rothamsted Research, a renowned agricultural science research centre. This free virtual event focused on the importance of sulphur in boosting crop production and for effective nutrient management, as well as a deep dive into the latest data insights.
Watch the recording of the webinar here.
Soil sulphur levels: a less visible but critical challenge
Last year’s heavy rainfall visibly affected fields where nitrogen applications were delayed or absent due to ground conditions, or in trial fields where nitrogen was not applied. Nitrogen’s mobility made its deficiency more noticeable, but sulphur—a nutrient with similar mobility—has quietly faced the same challenges. While its impact might not seem as dramatic as nitrogen’s, sulphur is vital for crop yield, quality, and the effective uptake and utilisation of nitrogen.
Despite its importance, sulphur often doesn’t receive the attention it warrants. However, data from leading laboratories over the last two years highlight the extent of the problem. For instance:
- NRM’s 2023-24 winter wheat tissue samples: over 40% were deficient in sulphur
- Lancrop’s cereal grain analysis: nearly 70% of samples were low or slightly low in sulphur, with the percentage of low samples more than doubling in 2024 compared to the previous year (PDA, 2024).
These findings strongly suggest that last year’s wet conditions exacerbated sulphur deficiencies across a wide range of crops.
The current season appears to be continuing the trend of challenging weather. Although many areas have recently experienced a respite from the rain, sulphur levels are likely to remain low this year. Farmers must plan accordingly to prevent potential yield and quality losses.
The role of organic materials in improving sulphur levels
While organic materials like slurries, manures, and digestates can supply sulphur, the quantities and availability of the nutrient vary widely. Research has shown that sulphur availability in cattle slurry can range from as low as 5% to as high as 55%, depending on feeding and storage practices.
These variations are influenced by factors such as:
- Conversion to organic sulphur: this form is less immediately available to plants
- Reduction to sulphide: another form of sulphur that plants cannot readily utilise.
Due to these uncertainties, relying solely on organic sources to meet a crop’s sulphur requirement is risky unless soils have received consistent manure applications over a long period of time.
Early planning is key for sulphur level management
Given the likelihood of sulphur deficiencies this season, it’s essential to plan analysis in early when making nutrient management plans. Whether through targeted fertiliser applications or supplementary organic sources, addressing sulphur requirements proactively will ensure crops have the nutrients they need to thrive.
NRM provides UKAS accredited soil analysis, as well as manure and slurry testing services to help you determine nutrient content and requirements. With accurate, timely data, you can make informed decisions on application rates, saving on fertilisers and boosting productivity. Get in touch today or speak to your agronomist.
By staying ahead of these challenges, growers can safeguard both yield and quality, even in the face of unpredictable weather patterns.
References
https://www.pda.org.uk/sulphur-levels-on-the-low-side-following-extreme-wet-conditions/
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