Controlled Release Fertilizers vs Slow Release Fertilizer

A common misconception is that Controlled Release Fertilizers (CRF) and Slow Release Fertilizers (SRF) are the same. Both deliver nutrients over a duration but are completely different products. The difference lies in the way they release the nutrients.

Controlled release fertilizers are affected by only one factor. Soil temperature is the only factor that affects the release of nutrients. Plant nutrients are released from controlled release fertilizers at a predictable and sustained rate. Controlled release fertilizers only come in the granular form where the coating thickness regulates the nutrient release.

Slow Release Fertilizers on the other hand are affected by many factors. Factors such as soil temperature, moisture, microorganisms, surface area and pH can affect the release of nutrients. Slow Release Fertilizers come in granular, nugget or packet/sachet forms where the release mechanism varies widely.

The table below compares the different types of Controlled Release Fertilizer and Slow Release Fertilizers currently available in the market.


Table Comparison of Controlled vs Slow Release Fertilizer

CharacteristicSK Cote CRF SCUIBDU/MU/UF NuggetInhibitors
TechnologyPolymer CoatingSulphur Coating Urea Reaction Product CompressionNitrification/Urease Inhibition
Release MechanismDiffusionRupture of coatingIBDU: Hydrolysis

MU/UF: Microbial activity
Smaller surface area Inhibition of enzymes
Longevity2-24 months 2-3 monthsIBDU: 90 days

MU: 12 weeks

UF: 12 weeks
2-4 months Depends on soil moisture and bacteria
Release Controlling FactorTemperatureMicrobial activity, moisture, temperature.Microbial activity, moisture, temperature, pH, organic matter.Microbial activity, moisture, temperature, pH. Microbial activity, moisture, temperature, pH.
Controlled Release100% 40-50%20-85%30-50% 0


In conclusion, Controlled Release Fertilizers are far superior to Slow Release Fertilizers. The reason is because it is the most advanced technology in the field of enhanced efficiency fertilizers. Only one single factor controls the release of nutrients over a predetermined period, therefore a more predictable result can be obtained.

To know more about SK Cote range of controlled release fertilizers please visit our product page.

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