You’ve heard the saying, “the right tool for the right job.” In agricultural production, the saying should be changed to “the right chemical for the right job.” Ammonium sulfate and calcium sulfate, commonly known as gypsum, are both products that are important to agriculture. They share one trait in common – the chemical sulfur is part of their makeup – but that is where the similarities end.

1. How Do Ammonium Sulfate and Gypsum Differ?
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Ammonium Sulfate and Gypsum
You’ve heard the saying, “the right tool f or the right job.” In agricultural production, the saying
should be changed to “the right chemical f or the right job.” Ammonium sulf ate and calcium sulf ate,
commonly known as gypsum, are both products that are important to agriculture. They share one
trait in common – the chemical sulf ur is part of their makeup – but that is where the similarities
end.
Ammonium Sulfate, (NH4)2SO4
Ammonium sulf ate is a non-hazardous, nitrogen-rich f ertilizer that also helps lower soil pH. The
nitrogen in ammonium sulf ate tends to be stable, so it is available throughout the growing
season. This reduces the need f or repeated applications. Applying ammonium sulf ate to alkaline
soil not only adds needed nitrogen, its acidif ying capability helps make soil micronutrients such as
calcium, boron and magnesium more readily available to growing plants. Ammonium sulf ate
f ertilizer can be used on acidic soils as well, but will require alternate lime applications to prevent
the soil pH f rom decreasing.
Ammonium sulf ate is highly soluble, so its
impact on soil f ertility and pH is immediate. Its
solubility also makes it an ideal addition to
glyphosphate-based herbicide applications by
substantially increasing herbicide ef f ectiveness;
using a slightly acidic spray allows the liquid to
better penetrate plant tissues which makes the
herbicide more ef f ective. Hard water is also
known to bind with the glyphosphate molecules
and render them inef f ective; ammonium sulf ate
added to the water counteracts hardness. It has
been f ound that ammonium sulf ate f ertilizer is
one of the best nitrogen sources f or soil crops such as soybeans and increases the production
of sulf ur-bearing amino acids in legumes and alf alf a. Ammonium sulf ate is a non-hazardous
byproduct derived f rom the production of Caprolactam.
Gypsum, CaSO4·2H2O
By contrast, gypsum is a soil amendment rather than a f ertilizer. It contains no nitrogen or other
macronutrients, so f or the purposes of f ertilization, gypsum needs to be used in conjunction with
a nitrogen source such as urea. Gypsum does help to stabilize the nitrogen in urea f ertilizer and
reduces volatilization. Gypsum is used primarily to loosen clay soils and to reduce the sodium
content of sodic soils as well as to add calcium. Gypsum is mined f rom rock sources, pulverized
and ref ined; it takes a long period of time to degrade completely into the soil. This is a positive
when it is used to reduce soil compaction and increase the f riability of clay, but tends to be a
negative when the need f or increased soil calcium is urgent. Even though gypsum is a sulf ate
compound, it does little to change soil pH; one soil testing lab has stated that it is the impurities
in lower grades of gypsum that act to change pH. A high grade gypsum is pH neutral.
Virginia soils range in pH f rom acidic in the

2. eastern regions to alkaline in the mountainous
areas. Find out your soil’s pH and f ertility level
through soil testing, and then purchase and
apply the right products in the right amounts to
make any needed adjustments. Commonwealth
CIS is a distributor of high quality ammonium
sulf ate and can provide your f arm with
ammonium sulf ate by the 50 pound bags, 3000
pound bags or supersacks. Commonwealth CIS
also provides ammonium sulf ate to manuf acturing f irms and to the tanning industry.
Image Credit:
Soil Component Name in Virginia, By J. Albert Bowden II
Post Emergence Stomp, by Chaf er Machinery
Gypsum, by Kevin Walsh
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Need Help Purchasing, Storing, Or Shipping Ammonium Sulfate?
Contact Commonwealth Industrial Services Today!
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Industrial Services
Commonwealth Industrial Services, Inc. (CIS) is an industrial services company
located in Hopewell, Virginia. Although historically a service business, CIS’ primary
prof it center is the packaging and resale of ammonium sulf ate.
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