Iron is one of the essential elements for plant growth. Iron deficiency results in a decrease in chlorophyll and causes chlorosis of young leaves. Slag and converter sludge are by-products of Isfahan steel factory which contain iron oxides and thus are recommended for correction iron chlorosis. Although positive effects of application of these products on iron chlorosis and plant yield have been indicated, however their cumulative and residual effects of application have not been studied yet. A 3 years field study was conducted to investigate the residual and cumulative effects of these two compounds yield, and uptake Fe, Zn, Cu, Mn, Ca, Mg and P by sorghum and AB-DTPA extractable of these elements from the soil. This study was conducted in Khazaneh research field of Isfahan University of Technology. A split plots in a complete randomized block design with ten treatments and three replicates was used for three consecutive years. The treatments were foliar application Fe-EDTA chelats, converter sludge and slag, 1, 2, 3 and 4 times as much as soil test recommends, (based on DTPA-extractable Fe of soil and that of compounds) and a control. In the first year, three blocks and ten plots (12×3 m) in each block, were all treated. In the second year one third of each plot (4×3 m) was left untreated and the rest two third was treated. In the third year, two third (8×3 m) of the each plot was not treated. Sorghum was planted each year and in the third year plants were harvested after 3 months. soil samples(0-20 cm depth) were collected after the plant harvest. AB-DTPA extractable Fe, Mn, Zn, P, Cu, Pb of soil samples, plant dry matter yield and Fe, Mn, Zn, Ca, Mg, P and Cu concentration of plant samples determined. Results showed that application of slag and converter sludge increased the AB-DTPA extractable Fe, Mn, Zn, Cu, Pb of soil samples. The increase was proportional to the rate and the application times. Converter sludge had the largest cumulative and residual effects on AB-DTPA extractable Fe, Zn, Pb of soil. The largest cumulative and residual effects on AB-DTPA extractable Mn were observed for different slag treatments. Application of slag and converter sludge resulted in a significant increase in dry matter yield. The increase was proportional to the rate and the application times. Iron concentration of plant increased with slag and converter sludge treatments but the increase was not significant probably due to the dilution effect. Plant uptake Fe, Mn, Zn, Ca, Mg, P increased significantly with the amendment rates and years of application.