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How It Works: Smart Nutrition™ MAP+MST®

Aug 11 2023

Boost your soil's performance

Smart Nutrition™ MAP+MST® is one of the most efficient dry fertilizer systems for delivering key nutrients to your crops when they need it most. This new granular fertilizer technology uses a unique integration of sulfur, phosphate and nitrogen to maximize crop nutrition and boost growth (9-43-0-16S) while providing a proven handling experience. But how does it work? The answer starts with an examination of the fertilization process at a microscopic level.

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Pure elemental sulfur is inert, hydrophobic and requires oxidation, e.g., converted by microbes, to sulfate before plants can utilize it. The problem with traditional elemental sulfur granules is they can take months or years to oxidize and become plant available due to the large sulfur particle size. The large particle size limits the volume of the granule that can be “worked on” by the microbes in the soil. In this case, a smaller granule size is preferred, as microbes can convert sulfur to sulfate more quickly and supply the crop with a much-needed nutrient. Micronized Sulfur Technology (MST) is a patented technology under license by Sulvaris Inc. where elemental sulfur is micronized. Smart Nutrition MAP+MST integrates that micronized sulfur directly into the manufacturing process of mono-ammonium phosphate granules (MAP) to deliver a uniform distribution of MST within the MAP granule.


Sulfur is widely recognized as an important part of a balanced crop nutrition program. Growers currently have options to apply sulfur as a liquid or solid fertilizer in the form of either sulfate, which is mobile in the soil, or elemental sulfur, which is immobile until it is oxidized by soil microbes. Both traditional sources have their limitations due to the trade-off involved (e.g., slow-release speed, risk of leaching, etc.). A newer option on the market is Smart Nutrition MAP+MST, a homogeneous, co-granulated fertilizer product that directly addresses these trade-offs. The patented MST process converts the elemental sulfur, which is a byproduct of oil and gas processing, into ultra-fine elemental sulfur particles, resulting in an average size of 15 microns.


Soil microorganisms are central to the natural process of oxidizing the elemental sulfur into sulfate. But to make the conversion, the microbes need access to the surface of the elemental sulfur. If sulfur particles are large, the surface area exposed for oxidation is small, and conversion rates slow down. When elemental sulfur particles are small, like with MST, there is a much larger surface area available. As particle size decreases, the total surface area available for microbial activity increases exponentially, coupled with uniform distribution of MST within the MAP granule, allowing for more rapid conversion to sulfate and better performance.


Because of these advantages at the microscopic level, Smart Nutrition MAP+MST offers versatility for sulfur management and often has benefits over sulfate forms. Since elemental sulfur oxidation is a biological process, the rate at which MST is converted to sulfate is highly temperature and moisture dependent. When soils are cold, the MST remains in elemental form. As soil temperatures warm, biological activity increases and starts converting the elemental sulfur to sulfate. This allows for applications of Smart Nutrition MAP+MST in the fall, without fear of sulfate losses, and slow release in the spring, matching crop needs. In U.S. field trials, Smart Nutrition MAP+MST has been shown to deliver an adequate supply of sulfur to crops. For comparison, these tests were always measured against equivalent sulfur rates of ammonium sulfate (AMS), a readily available sulfate sulfur source. The results indicate Smart Nutrition MAP+MST supplies adequate sulfur to maximize yields, matching sulfur availability from AMS applications, while protecting it from potential losses.

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