Get More from Every Hectare with POLY4 Grassland Fertiliser

Thomas Bell is supplying POLY4®, a natural, multi-nutrient fertiliser designed to help UK grassland farmers improve forage yield, quality and nutrient efficiency.

Getting the most from every hectare is increasingly important for livestock farmers, with grassland soils under pressure from nutrient deficiencies and the rising importance of efficient nutrient management.

Available through Thomas Bell, POLY4 offers a different approach to grassland nutrition. Made from natural polyhalite mineral mined in Yorkshire, it provides four essential nutrients in one application: potassium, sulphur, magnesium and calcium.

Four nutrients. One application.

POLY4 delivers a gradual supply of nutrients throughout the growing season, supporting sustained grass growth, root development and nutrient uptake.

Its nutrient analysis is:

• 14% potash (K₂O)
• 48% sulphur trioxide (SO₃)
• 6% magnesium oxide (MgO)
• 17% calcium oxide (CaO)

Sulphur is particularly important for grassland performance, helping plants make better use of applied nitrogen and convert it into protein. Without sufficient sulphur, nitrogen use can become less efficient, potentially limiting grass growth and forage quality.

POLY4 provides sulphur without nitrogen, making it suitable for use alongside nitrogen fertilisers and particularly relevant to clover, herbal leys and multi-species swards.

Supporting yield and forage quality

UK field trials comparing POLY4 fertilisation programmes with standard nitrogen, phosphorus and sulphur (NPS) programmes have demonstrated encouraging results.

Across five UK grass trials conducted between 2014 and 2022, the reported average results included:

• 11% higher dry matter yield
• 4% higher crude protein yield

The leaflet also reports a 10% improvement in nitrogen use efficiency across 68 global trials covering various crops.

For a productive grass silage system, the results indicate the potential to produce more forage and improve its protein value, helping farmers make better use of home-grown feed.

What could this mean for your farm?

Based on the trial results and typical forage values, the POLY4 leaflet estimates additional forage value of approximately £122–£185 per hectare.

This example assumes a baseline grass silage yield of 12 tonnes of dry matter per hectare per year, with an additional 730kg of dry matter and a 4% increase in crude protein yield. Actual results and financial returns will depend on soil nutrient status, growing conditions, application strategy and farm management.

Flexible grassland nutrition

POLY4 can be applied as a straight fertiliser alongside a flexible nitrogen programme or supplied in a range of blends. Its combination of potassium, sulphur, magnesium and calcium can help replace nutrients removed through grazing and silage production.

With nutrient requirements varying between grazing systems, silage fields and clover or herbal leys, application rates should be tailored to soil analysis, crop requirements and the farm's nutrient management plan.

Speak to Thomas Bell about POLY4

As a distributor of POLY4, Thomas Bell can help grassland farmers explore how this multi-nutrient fertiliser could fit into their grassland nutrition programme.

Contact the Thomas Bell team to discuss POLY4 availability, suitable applications and your fertiliser requirements.

Call 01652 652933‍

POLY4 is an Anglo American product. Trial results and potential forage values are based on the information provided by Anglo American and are not guaranteed outcomes. Application rates and suitability should be assessed for individual farm conditions

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