Why the ortho-ortho isomer matters in Fe-EDDHA specifications

Set up the comparison

Request separate results for total iron, chelated iron and the ortho-ortho EDDHA fraction. Hold water quality and pH constant when comparing grades.

Measurements to record

Iron chelated by the ortho-ortho isomer (Mass fraction as Fe). Confirm that the percentage denominator is the mass of the commercial product. Use the same method for comparisons. Total iron (Mass fraction as Fe). Also check soluble iron, chelated iron and the ortho-ortho fraction. Record the sample ID and method revision for repeat testing.

Interpreting the results

Keep iron attributable to the ortho-ortho chelate separate from the isomer percentage of the ligand. Neither value can be substituted for total iron in the product.

What to record

• Total iron
• Chelated iron
• Ortho-ortho isomer
• pH
• Trial water

Technical references

• Yara greenhouse nutrient solution guide: iron content and ligand data for Q48 ↗

Products and processes