What does critical relative humidity index (CRHI) mean?

This is the point at which a fertilizer granule will absorb moisture and begin to degrade (physically). Temperature is a considerable factor for SINGLE or unblended products. When 2+ fertilizer products are combined in blends, there are a multitude of variables and factors that come into play that need to be taken into consideration.

Key understandings for granular fertilizer blending

• The more fertilizer products in the blend, the greater the potential for caking or fertilizer binding together.
• The higher the amount of nitrogen and sulfur in the blend, the greater the chance of moisture absorption.
• The higher the solubility of the individual fertilizer products, the increased chance of reacting with other products in the blend. Remember – soluble formulations are required for plant uptake, optimal agronomy and practicality.
• Poor quality/dusty fertilizer which creates increased surface area, increases caking causing buildup/plugging of application equipment.
• The longer fertilizer blends sit under humid conditions the worse handling/flowability of the fertilizer becomes.
• Warm fertilizer in cold conditions and vice versa, cold fertilizer in warm conditions creates condensation and potential caking.

Practices to improve the CRH of granular fertilizer blends

• Low to no dust (potash is the worst of the macros)
• Low to no Urea & Sulfur
• Low humidity or moisture
• On demand blending to avoid blends sitting for lengthy periods
• Monitor changes in external temperatures
• Addition of AgReady diatomaceous earth

Visit NexusBioAg's full portfolio of Granular Micronutrients here. 

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