Cationic speciation in nutrient solutions as a function of pH

Abstract

The pH of a nutrient solution is a property that is inherent to its composition. Changing the pH of a nutrient solution affects its composition, elemental speciation and bioavailability. The term ‘speciation” indicates the distribution of elements among their various chemical and physical forms like: free ions, soluble complexes, chelates, ion pairs, solid and gaseous phases, and different oxidation states. For a standard nutrient solution elemental speciation is calculated for a pH range from 2 to 9. For each cation the formation of precipitates, ion pairs, complexes, and chelates is illustrated as a function of pH. The calculation of elemental speciation in nutrient solutions is an indispensable tool in the design, the analysis and the interpretation of experiments with the mineral composition of nutrient solutions in plant nutritional research.