Not All Sulfur Fertilizers Are Created Equal


granular ammonium sulfate vs. granular elemental sulfur comparison

Sulfur is an important nutrient in soybean production, playing a vital role in the growth and development of plants. Including plant-available forms of sulfur in crop nutrition plans can help maximize yield potential. However, not all forms of sulfur are created equal when it comes to delivering this essential nutrient when the soybean plants need it most.

“The form of sulfur makes all the difference in what is actually available to the plant roots to actually absorb, take up and use,” said AdvanSix Senior Agronomist Mercedes Gearhart. “Sulfate is the only form of sulfur that the plants are able to take up.”

The two most common supplemental sulfur sources for soybeans are ammonium sulfate (AMS) and elemental sulfur. But they are quite different when it comes to effectiveness.

Granular Ammonium Sulfate vs. Granular Elemental Sulfur comparison

Ammonium sulfate (AMS) is a dry granular fertilizer containing 21% ammonium-N and 24% sulfate-S.

Elemental sulfur (S) is a dry sulfur bentonite or co-granulated sulfur product.

Elemental S is water-insoluble and must be oxidized by soil microbes into sulfate before it can become available to be utilized by the plant.

AMS is highly soluble in water and readily available, so it immediately delivers sulfate sulfur to the plant roots once incorporated into the soil solution. This makes it a preferred option that can be used to correct in-season deficiencies.

Share the AMS vs. Elemental Sulfur infographic with your customers by downloading a PDF version here.

As you are making fertilizer decisions, take time to consider planting date, soil type, the nutrient analysis of your field, the organic matter composition of your field and the yield potential of your soybean variety. Combined, these factors can help you decide what fertilizer option is best suited to your crop.

In most cases, when it comes to sulfur nutrition, AMS is your best bet for maximizing ROI and yield potential.

Learn more at