Comparison of Application of Iron Oxide, Sequestrin and Iron Sulfate in the Presence of Manure and Sulfur on Fe Uptake by Soybeans

The use of iron (Fe) fertilizers is the most effective methods to deal with Fe deficiency in calcareous soils for agricultural purposes. Use of cheaper and available resources has been the focus of researchers. In this study, the effect of different sources of Fe fertilizer on the availability of Fe in soybean in a completely randomized design with factorial arrangement including three factors of different sources of Fe fertilizer (zero, Fe-sequestrin, Fe-sulfate and Fe-oxide with concentrations of 5, 30 and 50 mg of Fe per kg of soil, respectively), decomposed cow manure (0.5 and 1.5% by weight) and elemental sulfur in the presence of Thiobacillus bacteria (zero and 25 mg kg-1 and thiobacillus 1.8% of sulfur) in three replications. In 2019, it was studied in the research greenhouse of the Faculty of Agriculture, Ferdowsi University of Mashhad.The results showed that concentration and absorption of Fe in shoots in fertilizer treatments was higher than that in the control. Application of iron oxide alone, with manure, with sulfur and application of iron oxide with manure and sulfur could make a significant difference in increasing the concentration and absorption of Fe with other treatments. Use of iron oxide increased iron concentration by 1.24, 1.36 and 1.69 times and Fe uptake by 1.11, 1.28 and 1.73 times compared to sequestrin, iron sulfate and iron oxide treatments in shoots of soybean in the shoots. Application of ferrous sulfate alone did not differ significantly in increasing the concentration and absorption of Fe compared to treatments of ferrous sulfate with manure and with sulfur. In addition, no significant difference was observed between Fe uptake in sequestrin alone and manure. According to the results, to increase the efficiency of iron oxide, it is recommended to use it with manure and sulfur as a suitable alternative.