Assessment of nutrient depletion by weeds under biofortification and weed management practices in finger millet (Eleusine coracana L.)

Abstract

A field experiment was conducted at Udaipur, Rajasthan during the kharif seasons of 2023 and 2024 to evaluate the effect of zinc and iron biofortification in combination with different weed management practices on weed dynamics and nutrient depletion. The experiment was laid out in a split-plot design with three replications. Four biofortification treatments were assigned to main plots: B0: Recommended Dose of Fertilizer (RDF) control, B1: RDF + 25 kg ZnSO₄ + 20 kg FeSO₄ as soil application, B2: RDF + 0.5% ZnSO₄ + 0.5% FeSO₄ as foliar application, and B3: RDF + soil application of 25 kg ZnSO₄ + 20 kg FeSO₄ combined with 0.5% ZnSO₄ and FeSO₄ foliar spray. Five weed management practices were allotted to subplots, W0: weedy check, W1: hand weeding twice at 20 and 40 DAS, W2: atrazine 500 g ha⁻¹ as pre-emergence, W3: metsulfuron methyl + chlorimuron ethyl 4 g ha⁻¹ as post-emergence, and W4: bispyribac-sodium 25 g ha⁻¹ as post-emergence. The results revealed that combined soil and foliar application of Zn and Fe (B₃) significantly reduced weed density and biomass and minimized nutrient depletion compared to the control. Among weed management treatments, the weedy check recorded the highest nutrient depletion, whereas hand weeding twice (W₁) proved superior to all herbicidal treatments in reducing weed infestation and conserving nutrients. The study highlights the synergistic role of micronutrient biofortification and effective weed management in improving nutrient use efficiency and weed suppression under field conditions.