Ayesha Yousaf 1, Fahd Rasul 2, Muhammad Khizar Hayat 2,3, Fazaria Arshad 1 and Md. Nahid Mahmud 4
1Department of Botany, Faculty of Sciences, University of Agriculture Faisalabad, 38040, Faisalabad, Pakistan. 2Agro-climatology Lab, Department of Agronomy, University of Agriculture Faisalabad, 38040, Pakistan. 3Department of Field Crops, Faculty of Agriculture, Sakarya University of Applied Sciences, 54580, Sakarya, Türkiye. 4College of Agricultural Sciences, IUBAT-International University of Business Agriculture and Technology, Dhaka 1230, Bangladesh.
*Corresponding author: ayeshayousaf080@gmail.com
White radish (Raphanus sativus L.), a popular and nutritious root crop, is often grown using wastewater irrigation in water-scarce regions, leading to heavy metal accumulation and human health risks. This study evaluated a pragmatic solution using soil-applied biochar and foliar-applied L-methionine to mitigate these hazards. The research was conducted at the Agronomy Farm, University of Agriculture, Faisalabad, using a Randomized Complete Block Design (RCBD) with a split-plot arrangement. Factors included water sources (canal water, canal water + biochar, wastewater, wastewater + biochar) and foliar L-methionine concentrations (0, 30, 60, and 90 mg L⁻¹). The results demonstrated that the combined application of biochar and 90 mg L⁻¹ L-methionine significantly enhanced growth and safety profiles. Specifically, the application of biochar and methionine led to a substantial reduction in heavy metal uptake, with Cadmium (Cd) reduced by 33%, Lead (Pb) by 28%, and Zinc (Zn) by 22% in radish roots compared to wastewater irrigation alone. Furthermore, plant productivity improved significantly, with root fresh biomass increasing by 42% and root dry weight by 38% under the wastewater + biochar treatment supplemented with 90 mg L⁻¹ methionine. These interventions also improved physiological resilience, as evidenced by higher chlorophyll content and increased stress-tolerance markers like proline. Ultimately, this study implies that integrating biochar with L-methionine serves as a highly effective, low-cost strategy to secure food safety and enhance crop yields in regions forced to rely on contaminated wastewater for agriculture.