Effect of soil pollution of Savar areas and fertilizer management on yield and nutrient accumulation in maize

Abstract

Industrial soil contamination is an emerging threat to crop productivity and food safety in peri-urban Bangladesh, particularly around the Savar industrial zone where tannery effluents contribute to elevated levels of chromium (Cr), cadmium (Cd), and lead (Pb). This study examined the effects of soil pollution and fertilizer management on the growth, yield, and nutrient accumulation of maize (Zea mays L.) grown in contaminated soils of Savar. The experiment, conducted from November 2022 to January 2023, followed a Randomized Complete Block Design with four fertilizer treatments: T₀ (control), T₁ (recommended dose of chemical fertilizer), T₂ (75% chemical fertilizer + 25% cow dung), and T₃ (50% chemical fertilizer + 50% cow dung). Fertilization significantly improved vegetative and reproductive growth parameters, advancing leaf development by 3-4 days and increasing plant height by 11-12% compared to the unfertilized control. Integrated nutrient management (T₂ and T₃) delayed bud, tassel, and silk emergence by 5-10 days, extending the vegetative phase and enhancing assimilate accumulation. Total grass yield increased by approximately 35%, with the highest yield (645.3 g plant⁻¹) recorded in T₃, accompanied by a 16% increase in biomass dry weight. Fertilization also elevated macronutrient concentrations-P (by 61-67%) and K (by 85%)-and improved micronutrient accumulation, including Zn, Fe, Mn, and Cu (by 25-60%). While Pb concentration rose slightly under fertilization, Cd accumulation decreased notably (by up to 41%) in organic-amended treatments, reflecting metal immobilization through organic complexation. Overall, the combined use of cow dung and inorganic fertilizer enhanced nutrient uptake, mitigated Cd toxicity, and improved yield performance under industrially polluted soil conditions. These results highlight the potential of integrated nutrient management to sustain maize productivity and reduce heavy-metal risks in contaminated peri-urban agricultural soils of Bangladesh.