Theoretical and practical studies on chelate‐ca‐ph system in solution

Abstract
The use of Fe chelates in agriculture for correcting Fe chlorosis is widespread. Stability diagrams are useful for expressing the equilibrium relationships between metal ions and chelates in soil systems. In this paper the chelate‐Ca‐pH relationships in solution were studied. Theoretical diagrams were compared to data obtained from the laboratory. Total Fe in solution is enhaced by the formation of Fe/B(OH)4‐ complexes. After speciation, the amount of Fe chelated in solution compared well with theoretical diagrams. The solubility of Fe3+ is discussed in relation to different solid phases.