Chemical-microbial mechanisms underlying a synergistic strategy combining low-accumulating wheat and soil amendment...

Global wheat production faces a serious threat from soils co-contaminated with Cd, Pb and As. A field study was conducted to evaluate soil amendment combining agricultural wastes with clay minerals on heavy metal(loid)s (HMs) accumulation in two widely studied wheat cultivars. The greatest effect was observed in JM229 at 3000 kg ha^-1, where grain bioconcentration factors decreased by 66.99% (Cd), 56.90% (Pb) and 78.97% (As), accompanied with enhanced soil fertility. Chemically, Cd and Pb immobilization via strengthened organic matter complexation was enhanced by the amendment-induced enrichment of unsaturated carbon structures, and As immobilization was governed by clay mineral adsorption with assistance from organic components. From a microbiological perspective, the amendment reshaped soil microbial community by enriching key taxa (Massilia, Nocardioides and Aeromicrobium), increasing microbial network complexity, and promoting antioxidant-related functions, which collectively strengthened wheat resilience to HMs stress. Overall, soil amendment offers a sustainable strategy for immobilizing HMs and improving soil nutrients in contaminated farmlands.