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A greenhouse experiment was aimed at assessing the effects of poultry manure, sorghum, and clover residues (0 and 15 g kg-1) on the zinc (Zn) bioavailable fraction in contaminated calcareous soil using two chemical assay, diffusion gradient in thin films (DGT) and DTPA-TEA, and a bioassay with corn (Zea mase L.). The results showed that poultry manure, clover, and sorghum residues application increased dissolved organic carbon (DOC) by 53.6 and 36.1, and 9.2%, respectively, with respect to unamended soils, as well as decreasing soil pH by 0.42, 0.26, and 0.06 units, respectively. These changes did result in increases of Zn effective concentration (CE) and DTPA-Zn, and plant Zn concentration as a result of the increased exchangeable form of Zn. In the sorghum residues-amended soils, a reverse trend was observed for CE-Zn compared to the DTPA method. Correlation analyses revealed that unlike CE-Zn, DTPA-Zn had a positive correlation significantly with organic fractions that can be considered as an equivalent to the fact that the DTPA method had been overestimated Zn available to plants. The best correlations between corn metal concentrations and soil metal bioavailability were for CE-Zn using DGT technique, which also provided the best Zn bioavailability estimate. It is concluded that sorghum residues could be used to reduce the phytotoxicity risk of Zn in calcareous contaminated soil, and DTPA method is the less robust indicator of Zn bioavailability than DGT technique.