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September 20, 2023

Watch: How Bentonite Sulfur Fertilizer Breaks Down in the Soil

Ever wondered how degradable elemental sulfur is converted into plant-available sulfate in the soil? You’ve come to the right place. Keg River has developed this animated video to provide a simple and easy-to-understand overview of how it all works. From application to absorption!

Click the play button (above) to watch the video or read the transcript below (expanded with a few additional facts and insights).

Read: How bentonite sulfur fertilizer breaks down in the soil

Sulfur is a macronutrient that’s essential to healthy plant growth and development. It’s also widely used to manage soil pH. Degradable elemental sulfur fertilizers are a low-cost, high-analysis option that’s been around for decades.

But did you know that for plants to absorb elemental sulfur, it must first be converted to sulfate?

This is done courtesy of beneficial microbes in the soil. The most commonly known is thiobacillus, but there may be thousands of types of microbes that can carry out this task.

Did you know? With consecutive applications of elemental sulfur as part of an annual plan, microbial populations will grow – expediting conversion.

The makeup of bentonite sulfur fertilizer

Degradable elemental sulfurs are made with two key ingredients: Purified Elemental Sulfur and Premium Bentonite Clay.

The clay is mixed into liquid molten sulfur and formed into pastilles, perfectly sized to work in fertilizer blends.

Breakdown begins soon after application. (Just add water!)

This dry fertilizer can be fall or spring applied. It’s typically broadcast… but can also be banded. Fall broadcast application is recommended in northern climates where crops are not seeded over winter.

The clay absorbs moisture and begins to swell. This initiates a physical process that will force the sulfur to break into extremely fine particles.

A premium bentonite clay – like the kind found in Keg90S and Keg85S – provides superior absorption and swelling characteristics. This results in a more complete and more consistent breakdown.

The smaller the elemental sulfur particles become, the better – as it creates more surface area for beneficial microbes to feast on. Typically, microbes require particles to break down to a size of 1-180 microns for oxidation to occur.

As the sulfur is digested by the microbes, it is oxidized and converted into plant-available sulfate.

On average, 30 to 40% of elemental sulfur applied will be converted per season.

Slow and steady conversion ensures season-long sulfur

Not all of the sulfur is converted at once. It takes place throughout the growing season, ensuring a steady supply of slow-release sulfate-sulfur to the crop.

On average, 30 to 40% of elemental sulfur applied will be converted per season. The rest is banked in the soil for future crops.

See how it works! Watch our animated video.

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