The aim of this research was to understand the effectiveness of various agronomic managements in enhancing phytoavailability of Zn and alleviating its deficiency. The changes in chemical pools of Zn in soil solid and solution phases and the contribution to Zn phytoavailability of these forms was also investigated. The results showed that, agronomic managements significantly increased the exchangeable-Zn and organic-Zn fractions. Significant positive correlation between exchangeable-Zn and organic-Zn fractions in the rhizosphere with the total Zn uptake by wheat was found indicating that Zn in theses fractions are readily available for wheat. Also, our results showed that the agronomic managements changed Zn species in soil solution. However, the changes in Zn species were dependent on the agronomic managements. Chemical forms of Zn in solid and solution phases were more affected in the rhizosphere soil than in the bulk soil. The sensitivity analysis of artificial neural network (ANN) models showed that, the most effective managements affecting on grain yield and Zn bioavailability of wheat, were sewage sludge (10 and 5 t ha -1 ), cow manure (10 t ha -1 ), clover plant residue, rubber ash and powder, and cow manure (5 t ha -1 ), respectively. Keywords: Agronomic biofortification, Artificial neural network, Availability, Fractionation, Speciation, Wheat, Zinc.
