Foliar Barrier Agents Modulate Cadmium Accumulation and Transport in Spring Wheat (Triticum aestivum L.)

Wheat constitutes a significant agricultural crop in China and shows a notable tendency to easily bioaccumulate cadmium (Cd) when cultivated in contaminated soils, thereby posing substantial risks to human health. Foliar barrier agents can reduce Cd levels in the edible portions of wheat, facilitating compliance with the established safety standards for human consumption. In the present study, spring wheat was grown in pots in moderate to lightly Cd-contaminated soil. Five treatments with four foliar barrier agents, namely P, silicon-organic fertilizer (SOF), mancozeb (MZ), and microencapsulated fertilizer (MEF), were established to determine their impact on Cd content and cumulative Cd uptake and distribution across wheat organs. All four agents reduced Cd in wheat kernels, with SOF and MZ showing the most substantial reductions of 77.7% and 77.2%, respectively, and a 12% reduction in Cd distribution across wheat organs. These agents primarily block Cd transfer from stems and leaves to grain, ensuring food safety. MZ and SOF most effectively reduced Cd accumulation in wheat. All four agents reduced the target hazard quotient, with SOF yielding the greatest decrease. Thus, SOF is the optimal foliar barrier agent for wheat, supporting safe production on Cd-contaminated farmlands and advancing food security and sustainable agricultural development.