FAQs

All crops need sulfur to grow and form proteins. In fact, sulfur is considered to be "The Fourth Nutrient" behind nitrogen, phosphorus and potassium. Where sulfur is lacking, crop yield and quality will suffer. Plants can become spindly and stunted, and new growth turns a yellowish green color. See Crop Nutrition for more information on the importance of sulfur.

Years ago, crops got a good dose of sulfur from electric utilities that released sulfur dioxide through their smokestacks. However, the Clean Air Act has sharply cut back on sulfur dioxide emissions and crops are not getting as much "free" sulfur from the skies.

Traditionally, sulfur deficiencies have been most common in sandy soil types with low organic matter content. More recently, researchers have discovered that crops can become sulfur deficient even when organic matter levels are high. These "new" deficiencies are attributed to earlier planting dates and no-till/conservation-till farming - two trends that promote cooler soil temperatures that slow down the release of sulfur from the organic matter.

Start with a soil test to find out how much sulfur you have in your soils, then follow-up with a tissue test to find out how much of that sulfur is actually getting into the crop.

Unlike potassium and phosphorus, sulfur is not part of the routine soil test at most university and private labs. To get a sulfur analysis, you must specifically request it.

The tissue test for sulfur measures the amount of sulfur that is actually absorbed into the plant. It's a very useful tool for confirming suspected sulfur deficiencies. Like the sulfur soil test, the sulfur tissue test must be specifically requested. Many labs now have the capability to turn around sulfur tissue tests in a matter of days, allowing sufficient time for in-season applications of sulfur to correct deficiencies and prevent further yield loss.

It's often tough to differentiate sulfur deficiency and nitrogen deficiency because both cause yellowing of plant tissue. Sulfur deficiency tends to show up in newer leaves, while nitrogen deficiency tends to show up in older leaves.

Both. As a sulfur source, Sulf-N ammonium sulfate supplies S in the readily available sulfate form. As a nitrogen source, Sulf-N ammonium sulfate is extremely efficient because all of its nitrogen is in the ammonium form, which resists losses from leaching, volatilization and denitrification. Because Sulf-N ammonium sulfate supplies both of these vital nutrients in a form that is immediately usable to plants, it is a cost-effective choice.

Sulf-N ammonium sulfate supplies sulfur in the readily available sulfate form, the only form that crop roots can immediately absorb. Fertilizers that supply sulfur in the elemental form cannot be absorbed by crop roots until converted to sulfate by soil microbes. This is a process that can take up to one month or more, depending on soil temperatures - the cooler the soil, the slower the transformation.

Sulf-N ammonium sulfate supplies nitrogen in the dependable ammonium form. Ammonium nitrogen promotes higher yields than straight nitrate while resisting losses to leaching, volatilization and denitrification. That makes it often more effective than urea and UAN solution in conservation-till and no-till systems.

Yes, ammonium sulfate is an excellent fertilizer source for broadcast applications. In no-till and conservation-till systems, studies have demonstrated that broadcast ammonium sulfate is as efficient as injected UAN solution.

Yes, ammonium sulfate can be used in pop-up and 2-by-2 starter applications.

Residue left on the soil surface in no-till and conservation-till systems can promote N loss from volatilization when urea and urea-containing fertilizers like UAN solution are broadcast and not incorporated into the soil. Ammonium sulfate is not susceptible to volatilization loss because its N is in the ammonium form. University studies have demonstrated that ammonium sulfate can be broadcast on the surface of no-till and conservation-till soils with very little risk of N loss due to volatilization.

Sulf-N granular grade, now with improved size and uniformity, provides the ideal specifications for bulk blending with urea, MAP, DAP, potash, and other granular fertilizers. Sulf-N soluble grade readily dissolves in water to make an 8-0-0-9S solution that is compatible with other liquid fertilizers and fertilizer suspensions.

Many fertilizer dealers carry Sulf-N ammonium sulfate. Larger dealers are listed under Customer Links, or visit Contacts and e-mail us for the dealer nearest you.