The Effect of Biochar on the Growth and Uptake of Pb by Spinach (Spinacia oleracea L.) Grown in Contaminated Soil

Abstract

Agricultural soil contamination with lead (Pb) is a most serious problem because it adversely affects crop growth, soil quality and poses severe hazards to human health by way of its entry into the food web. A pot experiment was carried out to evaluate the interaction of Pb × biochar to assess the phytoremediation efficiency of spinach (Spinacia oleracea L.) plants in Pb-contaminated soils. The study’s findings that the application of biochar to soil at a rates of 75 and 150 g pot-1 significantly increased shoot and root length of spinach in Pb contaminated soil (21.87, 4.85%) and (35.86, 12.13%) in (T7, T8) and shoot and root dry weight (6.59, 68.95%) and (4.54, 32.57%), respectively, of Spinacia oleracea L. Pb content at 80 mg kg-1 contamination levels with respect to the non-amendment (T1). It was observed that biochar significantly affected the form of Pb concentration in Spinacia oleracea L. (P<0.05). The minimum and maximum Pb concentrations present in the shoot and root (0.07±0.01, 6.99±1.70 mg kg-1) and (0.17±0.01, 8.21±1.42 mg kg-1), respectively, are Spinacia oleracea L. grown in contaminated Pb 80 mg kg-1 soils. While the Pb absorption in shoot and root declined up to (25.72% and 21.04%) and (20.75% and 18.59%) in treatments T7 and T8 as compared to non-amendment T0, respectively, by the addition of biochar at 80 mg kg⁻¹ Pb stress. TF was <1 at all contamination levels, indicating limited Pb translocation. The results showed that the interaction between Pb × biochar reduced Pb uptake by the plant, with uptake decreasing as the biochar application rate increased. Therefore, it highlights the importance of biochar and its applications in promoting environmental sustainability and ensuring global food security.