This work is included in a wide field of research on the dynamics of synthetic chelates in calcareous soils of South‐East of Spain. Through the application of Freundlich isotherm to the process of formation‐decomposition of chelate FeEDDHA, equations of type: Cs= A . tn. Cmoare obtained, where A, n and m, are ctes., Cs, the concentration of iron chelated added to the soil, and t, interaction time of chelate with the soil. In this way we can predict the rhythm of the solution process of Fe in calcareous soils.