Mina Alipour Babadi, Mojtaba Norouzi Masir, Abdolamir Moezzi, Afrasyab Rahnama Ghahfarokhi, Mehdi Taghavi Zahedkolaei,
Volume 30, Issue 1 (spring 2026)
This study aimed to evaluate the effectiveness of iron (Fe) aminochelate application methods on Fe chemical speciation in the soil solution, as well as Fe concentration and uptake in sunflower seeds (Helianthus annuus L. cv. Oscar). The experiment was conducted in a randomized complete block design with three replications at the research field of Shahid Chamran University of Ahvaz. Treatments included two application methods (seed priming and fertigation) and three Fe sources: Fe–glycine aminochelate [Fe(Gly)₂], Fe–methionine aminochelate [Fe(Met)₂], and ferrous sulfate (FeSO₄·7H₂O), along with an unfertilized control. Fe speciation was determined using Visual MINTEQ software. Results indicated that Fe aminochelates, [Fe(Met)₂], significantly decreased soil pH and increased DTPA-extractable Fe (by 35.7%), seed Fe concentration (by 13.5%), and seed Fe uptake (by 79.1%) compared with the control (p < 0.01). Application of Fe fertilizers also significantly enhanced the concentrations of dominant Fe species (Fe²⁺ and FeSO₄(aq)) in the soil solution, with the highest Fe²⁺ level (3.1-fold higher than the control) observed under [Fe(Met)₂] seed priming. Strong and significant positive correlations between Fe²⁺ and FeSO₄(aq) concentrations and both DTPA-extractable Fe (r = 0.88** and r = 0.89**, respectively) and seed Fe uptake (r = 0.84** and r = 0.87**, respectively) highlight the pivotal role of these species in improving Fe bioavailability and uptake by plants in calcareous soils.
