Department of Soils, Haryana Agricultural University, Hissar
Investigations to study the effect of different sources and amount of Zn with graded doses of S on utilization of iron by soybean plants were carried out in greenhouse at Haryana Agricultural University, Hissar. Sulphur was applied at 0, 40, 80 and 120 ppm through K2SO4 and Zn at 0, 5 and 10 ppm through ZnCl2, Zn-EDTA and Zn-Rayplex. At lower levels (40 and 80 ppm) the application of S increased Fe concentration in all plant parts at both the stages of crop growth but higher level (120 ppm) S decreased Fe concentration in all plant parts. Application of 5 and 10 ppm Zn significantly decreased the Fe concentration in leaves, stem, podhusk and grain. Among the sources, maximum reduction in Fe concentration was found due to ZnCl2 followed by Zn-Rayplex and Zn-EDTA application. At maturity Fe content in different plant parts was in order: leaves>grain>stem> pod-husk. Zinc levels and Zn—sources interaction OD total Fe uptake revealed that 5 ppm Zn as Zn-EDTA gave the highest uptake of Fe at 110 days. The Fe concentration of leaves at 110 days gave negative correlation (r=-0.451**) with Zn uptake and positive correlation (r= +0.527**) with Fe uptake.
