Effect of Lead and Calcium (Pb×Ca) Interaction on the Growth and Dry Biomass of Fenugreek (Trigonella foenum-graecum L.) Grown in Contaminated Soil

Abstract

Agricultural soils contaminated with Lead (Pb) are a serious environmental concern because they have an adverse impact on crop growth, productivity and food security. A pot experiment was carried out during the Rabi season in 2024-25 at the Sheila Dhar Institute (SDI) experimental farm, University of Allahabad, Prayagraj, Uttar Pradesh, to study the effect of Pb×Ca interaction on fenugreek (Trigonella foenum-graecum L.) grown in Pb-contaminated soil. The pot experiment was set up using a completely randomized design (CRD) with nine treatments, which included three levels of Ca (0, 60, 120 mg/kg) and three levels of Pb (0, 20, 40 mg/kg), along with a control. Pb stress significantly (p ≤ 0.05) reduced shoot and root length and dry biomass, while increasing Pb uptake in plant tissues. In contrast, the application of Ca exhibited a mitigating effect on Pb toxicity. Among the treatments, 120 mg/kg Ca with 0 mg/kg Pb (T3) recorded the maximum shoot length (40.92 cm) and root length (8.95 cm), along with the highest biomass (10.02 g shoot and 3.11 g root per pot), and the lowest Pb uptake. In contrast, the treatment with 40 mg/kg Pb and no Ca (T7) exhibited the most severe toxic effects. Pb stress significantly (p < 0.05) decreased shoot and root length, as well as dry biomass, while increased Pb uptake in plant tissues. Calcium application significantly enhanced plant growth and reduced Pb accumulation, as evident from lower TF and BCF values. These findings suggest that using calcium can help in reducing Pb toxicity in fenugreek grown in Pb-contaminated soils, providing a promising way to improve plant health and yield in heavy metal-polluted soils.