Tentative critical values for Fe and Cu are 19.3 mg/kg Fe and 0.38 mg/kg Cu for Coca Cola and 73 mg/kg Fe and 0.96 mg/kg Cu for the DTPA method. The critical value for available Mn and Zn on the investigated inceptisols was 17.8 mg/kg Mn and 1.3 mg/kg Zn for Coca Cola® and 9.4 mg/kg Mn and 1.8 mg/kg Zn for DTPA. For Mn 49% of the variability in Mn concentrations observed in field grown winter wheat plants could be explained by Coca Cola‐extractable soil Mn, but only 39% when employing DTPA. Correlation coefficients for the relationship between Coca Cola‐extractable Fe, Zn, and Cu in soils and element concentrations in plants were the same as by means of the DTPA method. Compared to DTP A, Coca Cola extracted only 27% of iron (Fe), 38 % of copper (Cu), and 86% of zinc (Zn), but 165% of Mn. The overall extraction force of Coca Cola was similar to that of commonly used phosphoric acid methods. The main ingredients of Coca Cola, phosphoric acid, reducing sugar and carbon dioxide are well proven in common extraction recipes. Coca Cola has been found to be an excellent extractant for micronutrients in soils, particular for manganese (Mn).
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