Abstract
The nutritional value of Glycine max L. (soybean) and its yield potential for improving sustainability of agricultural systems has resulted into its increased production. Soybean crop has potential to replace the rice crop in the rice-wheat cropping system. However, the crop has shown high sensitivity towards iron (Fe) deficiency, and thus recorded major yield and nutritional quality losses. Thus, a three-year field experiment was planned to compare the impact of the application rate (0.5% and 1.0%) and number of sprays of FeSO4 on yield, Fe nutrition, and economic outcomes of soybeans. The Fe application posed a beneficial impact on the studied parameters due to an increase in enzymatic activity of Fe-containing enzymes. Among various treatments, maximum increase in grain and straw yield (3064 and 9341 kg ha−1, respectively) was obtained with 0.5% FeSO4 application at 30, 60, and 90 DAS over the control (2397 and 6894 kg ha−1, respectively). Similar results were attained for grain Fe concentration (69.9 mg kg−1) and Fe uptake in grain and straw (214 and 9088 g ha−1, respectively). The results were statistically non-significant, with the treatment in which 0.5% FeSO4 was applied at 30 and 60 DAS. The economic returns of soybean cultivation were also highest with 0.5% FeSO4 application at 30, 60, and 90 DAS with highest benefit; the cost (3.02) followed by treatment in which 0.5% FeSO4 was applied at 30 and 60 DAS. Thus, 0.5% FeSO4 application at 30, 60, and 90 DAS can be recommended for soybeans grown on sandy loam soil followed by 0.5% FeSO4 application at 30and 60 DAS to harness maximum yield, Fe concentration, and profitability.