Evaluation of Some Extraction methods for Determination of Corn Available copper in Some Calcareous Soils of Iran

The effectiveness of different extraction methods for the prediction of available Cu concentration was studied in 21 calcareous surface soils (0-30 cm) in western Iran. The greenhouse experiment was conducted with single cross 704 (SC-704) cultivar of corn plant (Zea mays L.) with three replications. The leaf chlorophyll index, shoot dry weight and shoot Cu concentration were measured at the end of the growing period (after 60 days). Various extractants were applied for extraction of soil available Cu, including DTPA, AB-DTPA, AC-EDTA, Hydroxylamine Hydrochloride, and Ammonium Oxalate. According to results, extracted Cu by various extractants was insignificantly correlated with plant growth indices. However, significantly correlation was found between The Log DTPA-TEA-Cu and Log Root-Cu content. The highest (25.9 mg kg-1) and the lowest (1.57 mg kg-1) concentrations of extractable Cu was extracted with ammonium oxalate and DTPA-TEA respectively. The most significant correlation coefficient (r=0.93**) was obtained between AB-DTPA and AC-EDTA extraction methods.  Results revealed that the DTPA-TEA was the most effective Cu extractant in this study.