The effect of Zinc application on the methods which can be used to determine available Iron content of soils

This research was carried out in order to find out the effect of zinc application on the methods which can be used to determine available iron content of paddy soils. For this purpose, an experiment was carried out in greenhouse conditions by growing maize. The effect of increasing rates of zinc application on biological indexes of maize plants was determined. Eight chemical extraction methods for available iron content of soils were used and these methods are: 0.005 M DTPA+0.01 M CaCl₂+0.1 M TEA; 0.005 N HCl+0.025 N H₂SO₄; 1 N NH₄Oac; 0.01 N Na₂EDTA+1 N NH₄Oac; 2 N MgCl₂; 0.01 M Na₂EDTA +1 M (NH₄)₂CO₃; 0.01 N Na₂EDTA and 0.005 M DTPA+NH₄HCO₃. The relationships between biological indexes and chemical extraction methods were determined at the end of the experiment. The highest correlation coefficient was determined with the method 0.005 M DTPA+0.01 M CaCl₂+0.1 M TEA. The iron content of maize plants decreased with zinc application and dry matter content increased with zinc application.