Potential of iron oxide-modified biochar in simultaneous mitigation of lead and nickel toxicity in wheat (Triticum aestivum L.)

Lead (Pb) and nickel (Ni) contamination of soil is a global environmental threat, compromising agricultural productivity, human health, and ecosystems. Therefore, it is imperative to develop new and sustainable approaches for the mitigation of Pb and Ni toxicity in crop plants. In the current study, iron oxide-modified biochar (FMBC) was prepared and evaluated to determine its effectiveness in improving wheat growth and reducing Pb and Ni uptake by wheat plants. In the pot experiment, varying levels of pristine biochar (BC) and FMBC were incorporated into Pb- and Ni-contaminated soil. The data showed that growth of wheat plants was significantly improved by FMBC application at its highest level (1.5 %) resulting in increased root, shoot, husk, grain dry weights, and root and shoot lengths. Similarly, FMBC (1.5 %) significantly increased photosynthesis, transpiration rates, stomatal conductance, intercellular CO₂, chlorophyll-a, and chlorophyll-b contents of wheat plants by 110.4 %, 44.5 %, 169.5 %, 47.6 %, 125 %, and 148 %, respectively. Plants treated with 1.5 % FMBC showed reduced oxidative stress in terms of suppressed hydrogen peroxide, electrolyte leakage, and malondialdehyde contents by 53.2 %, 52.7 %, and 41.3 %, respectively. FMBC application significantly reduced Pb and Ni bioavailability in soil and its uptake by plants. The FMBC amendment (1.5 %) decreased Ni concentrations in roots, shoots, husks, and grains by 31.6 %, 19.4 %, 24 %, and 24.3 % and Pb content by 60.1 %, 59.5 %, 79.6 %, and 76.1 %, respectively. The findings of the current study demonstrated that FMBC is an environment-friendly and sustainable amendment for reducing the risks associated with the uptake of Pb and Ni by wheat grown in contaminated soils.