Effects of iron and zinc applications on nitrogen fixation,yield and quality of second crop soybean varieties at different stages in Amik plain

In this study, it is aimed to determine the effects of Zn and Fe spray foliar application on nitrogen fixation, yield, and quality characteristics of the soybean plant grown as a second crop under Amik Plain conditions. The study was conducted in completely randomized design in split-split-plots with three replications and two planting seasons (2018 and 2019). Factors were places as varieties (Arısoy, Bravo, Nazlıcan) on main plot, growth stages (V3, R1, R3) on sub-plot, and foliar applications (Control, Zn, Fe, Zn + Fe) on sub-sub-plot and various phenological, morphological and quality parameters were examined. The highest yield was obtained from Nazlıcan (517.80 kg/da) and V3 stage (427.43 kg/da). Zn + Fe (481.13 kg/da) application was the highest yield, followed by Zn (435.52 kg/da), Fe (406.84 kg/da), control (369.81 kg/da). The highest protein content was obtained from Nazlıcan (34.33%) and R3 stage (33.22%). Zn (33.61%) application had the highest protein content, followed by Zn + Fe (33.23%), Fe (32.97%). The highest oil content was obtained from Arısoy (21.50%) and R3 stage (21.30%). Zn (22.02%) application had the highest protein content, followed by Fe (21.96%), Zn + Fe (21.49%). The two-year average protein and oil content of all factors was 33% and 21.08%, respectively. Considering the two-year averages of all factors, fatty acids were found to be linoleic acid 50.13%, oleic acid 24.83%, palmitic acid 11.82%, linolenic acid 8.80% and stearic acid 2.86%. As a result, it was observed that the Zn and Fe uptake of the plant was limited under Amik Plain conditions where the soil had high calcitic and pH. By applying foliar fertilization, it was determined that nutrients affect both morphological and quality features in soybean varieties positively.