Contents and Distrıbutions of Iron Fractions in Bafra, Çarşamba and Suluova Soils and Relationshıps with Some Soil Properties

The aim of this study was to determine contents and distributions of iron fractions in Bafra, Carsamba and Suluova soils and relationships with some soil properties. For this aim, 26 soil samples were taken from 0-20 cm depth of agricultural fields of Bafra, Carsamba and Suluova districts. Beside some physical and chemical soil properties, exchangeable iron (Exch-Fe), organic bounded iron (OM-Fe), manganese oxides bounded iron (MnOX-Fe), amorph iron oxides bounded iron (AFeOX-Fe), crystal iron oxides bounded iron (CFeOX-Fe) and residual iron (R-Fe) contents of soils were determined. According to mean iron fraction values, iron fractions ordered as follows; R-Fe (7800-19400 ppm Fe) > CFeOX-Fe (6000-11300 ppm Fe) > AFeOX-Fe (1100-6700 ppm Fe) > MnOX-Fe (3.90-158.9 ppm Fe) > Exch-Fe (0.8-2.4 ppm Fe) > OM-Fe (0.6-1.6 ppm Fe). The total iron content of the soil were found between 20000-34000 ppm. Manganese oxides bounded iron form had significant negative correlations with soil pH (r=-0.448*), total lime (r=-0.556**) and active lime (r=-0.448*) contents.  There was a significant positive relationship (r=0.674**) between MnOX-Fe and available Mn contents of soils.  While sand contents of soils gave significant negative correlations with CFeOX-Fe (r=-0.382*) and total iron contents (r=-0.467*), clay contents of soils had a significant positive correlation with total iron content (r=0.386*). In another word, total iron contents of soils increased with increasing clay contents in soils. It has been determined that sum of exchangeable + organic + manganese oxides bounded iron is diagonistic (effective) on the extractable iron by 0.005 M DTPA + 0.01 M CaCl2 + 0.1 M TEA (pH=7.3). The extractable iron content by 0.005 M DTPA + 0.01 M CaCl2 + 0.1 M TEA (pH=7.3) increased with increasing sum of exchangeable + organic + manganese oxides bounded iron of soils