COCA COLA(R) IS IT - THE UBIQUITOUS EXTRACTANT FOR MICRONUTRIENTS IN SOIL

Coca Cola(R) has been found to be an excellent extractant for micronut rients in soils, particular for manganese (Mn). The main ingredients o f Coca Cola(R), phosphoric acid, reducing sugar and carbon dioxide are well proven in common extraction recipes. The overall extraction forc e of Coca Cola(R) was similar to that of commonly used phosphoric acid methods. Compared to DTPA, Coca Cola(R) extracted only 27% of iron (F e), 38% of copper (Cu), and 86% of zinc (Zn), but 165% of Mn. Correlat ion coefficients for the relationship between Coca Cola(R) extractable Fe, Zn, and Cu in soils and element concentrations in plants were the same as by means of the DTPA method. For Mn 49% of the variability in Mn concentrations observed in field grown winter wheat plants could b e explained by Coca Cola(R)-extractable soil Mn, but only 39% when emp loying DTPA. The critical value for available Mn and Zn on the investi gated inceptisols was 17.8 mg/kg Mn and 1.3 mg/kg Zn for Coca Cola(R) and 9.4 mg/kg Mn and 1.8 mg/kg Zn for DTPA. Tentative critical values for Fe and Cu are 19.3 mg/kg Fe and 0.38 mg/kg Cu for Coca Cola(R) and 73 mg/kg Fe and 0.96 mg/kg Cu for the DTPA method. Besides the better results in extracting available micronutrient fractions from soils, f urther advantages of Coca Cola(R) as an extractant are its ubiquitous availability and readiness for use but also its easy and safe handling and the fact that the procedure has no harmful impacts on environment .