Methods for determination of available iron contents of olive grown soils in Bursa region

This study was conducted to select appropriate methods for the evaluation of available Fe status in olives grown in alkaline soils. For this purpose, 50 olive orchards were selected in the Iznik, Orhangazi, Gemlik and Mudanya districts of Bursa region by conducting an extensive survey before the research started in the Bursa region. A total of 100 compound soil samples were taken from 0 - 30 and 30 - 60 cm depths in early spring from the orchards, a total of 50 leaf samples were collected in January and 50 fruit samples were collected at harvest maturity. In determining the available Fe content of soils; Total Fe, Aqua Regia (3 HCl + 1 HNO3) (M1); 0,005 M DTPA + 0,01 M CaCl2 + 0,1 M TEA (M2); "Active Fe" (COONH4) 2.H2O + (COOH)2.2H2O (M3); 0,05 M HCl + 0,012 M H2SO4 (M4); 0,05 M EDTA (pH 7,0) (M5); 1 M NH4HCO3 + 0,005 M DTPA (pH 7,6) (M6); 0,01 M Na2EDDHA (pH 7,0) (M7) and 0,43 M HNO3 (M8) methods were used. According to results of the research, method of 0,05 M HCl + 0,012 M H2SO4 (M4) could be used for determination of available Fe status of olive grown soils in Bursa region.