Evaluation of Some Extraction for Determination of Corn Available Iron in Some Soils of East Azerbaijan Province

This research was conducted to evaluation of extraction methods for determining the available iron (Fe) and active Fe in corn plant (Zea mays L.) at 21 calcareous surface soil samples in the East Azerbaijan province. In a greenhouse experiment, corn plant single cross 704 cultivar has been cultivated with 3 replications. After 60 days, the plant growth parameters were measured. According to the results, DTPA and AB-DTPA had the highest linear correlation coefficient with growth indices of corn such as active Fe concentration, chlorophyll index, Fe content, fresh weight and shoot dry weight as well as with some physical and chemical properties of soils. AB-DTPA due to a correlation coefficient greater than DTPA and simultaneous extraction of multiple nutrients was chosen as the best extractant. On the average, rapid ammonium oxalate and AC-EDTA extracted the maximum and minimum amounts of Fe, respectively. The both of 1.5% o-phenanthroline and 1N HCl methods were suitable for measuring corn active Fe concentration. Significant correlation (r=0.66 ,p