Long-Lasting, Steady, and Gentle Sulphur Release

Sulphur is an essential crop nutrient. Farmers have a choice of sulphate fertilisers to help crop growth. However, as with all soluble plant nutrients, there are concerns that sulphates are prone to leaching – or being lost through the soil beyond the root’s reach – before they can be taken up by the crop.

Learning About Leaching

The UK’s University of Nottingham conducted a soil column test experiment, designed to compare the rate of release of sulphate from Polysulphate with that of other fertilisers.

Each soil sample, a depth or column of loam soil, had been previously leached of soil nutrients. Four different granular fertilisers – Polysulphate, ammonium sulphate, sulphate of potash and kieserite – containing equivalent rates of sulphur were added. The soil samples were flushed daily with de-ionized water and the leachate that drained away was measured for sulphate content.

Polysulphate’s Prolonged Nutrient Release Proven

The results of the sulphate release experiment show that sulphate in Polysulphate is released gently and over a prolonged period, for about 50 days. Which means that sulphur is released where it’s needed in the upper soil level, at the pace the plants need it, and for weeks.

Sulphate from other fertilisers is released much more quickly, and probably too quickly for crop roots to be able to capture it and use it over a long period, meaning unused sulphates are leached from the soil.

Understanding the nutrients required by crops, and when and how they are available, is an important step in helping make the right choice of fertiliser to apply in order to achieve the full crop performance.