Effect of foliar spraying with nano-iron and the addition of biofertilizer on soybean growth

Abstract

A field experiment was conducted to determine the effect of foliar spraying with chelated nano-iron and the addition of the biofertilizer EM1 on the growth of soybean plants. The experiment was carried out in the Al-Azawiya area of ​​Al-Musayyib district, north of Babylon Governorate, at a longitude of 32°47'53.9"N, and a latitude of 44°24'32.1"E. During the autumn growing season of 2025, a randomized block design (RCBD) with three replications was used. The experiment included three concentrations of nano-iron fertilizer (0, 1.5 g/L, and 3 g/L) and three levels of the biofertilizer EM1 (0, 2 ml L⁻¹, and 4 ml L⁻¹). The results showed that the third concentration of nano-iron fertilizer (3 g L⁻¹) was superior to the control treatment in terms of plant height, number of branches, number of leaves, leaf chlorophyll content, and leaf area.The results also showed that the third level of EM1 biofertilizer outperformed the control treatment in plant height, branch number, leaf number, leaf chlorophyll content, and leaf area. The interaction between nano-fertilization and EM1 biofertilizer was significant in growth characteristics. The interaction between the third concentration of nano-iron fertilizer (3 g L⁻¹) and the third level of biofertilizer (4 ml L⁻¹) resulted in the highest average vegetative growth indicators for plant height, number of branches, number of leaves, leaf chlorophyll content, and leaf area, surpassing the control treatment. We conclude that the use of nano-iron at a concentration of (3 g L^-1) alone or with the dual interaction treatment (between spraying nano-iron fertilizer and the EM1 biofertilizer) has a significant effect on all vegetative growth indicators for the studied traits and outperformed the growth indicators of the control treatment