Nano‐Biochar‐Assisted Intercropping Alleviates Fusarium Wilt of Faba Bean by Enhancing Rhizosphere Soil Health in Long‐Term Continuous Cropping Soil

ABSTRACT Long‐term faba bean ( Vicia faba L.) monocropping degrades soil and promotes Fusarium wilt. Intercropping and nano‐biochar (N‐BC) can improve soil health and suppress soil‐borne diseases. However, their combined effects on Fusarium wilt in faba bean remain unclear. This study assessed whether combining intercropping with N‐BC could improve faba bean rhizosphere soil health and reduce Fusarium wilt under prolonged continuous cropping. A pot experiment was conducted to compare faba bean monocropping with faba bean–wheat intercropping under an unamended control, biochar (BC), and N‐BC treatments. Fusarium wilt incidence and rhizosphere physicochemical and biological properties were assessed. Intercropping reduced disease incidence and disease index by 8.57%–34.53% and 8.32%–30.20%, respectively. Under intercropping, BC reduced these measures by 14.95% and 15.17% compared with the control. N‐BC further reduced them by 50.02% and 54.74% compared with BC. The combined treatment increased soil water content, macroaggregate proportion, organic matter, dissolved organic carbon, ammonium nitrogen, nitrate nitrogen, available phosphorus, sucrase, urease, neutral phosphatase, catalase, and polyphenol oxidase. It decreased bulk density and benzoic, cinnamic, p‐hydroxybenzoic, ferulic, and vanillic acids. These changes coincided with higher relative abundances of potentially beneficial bacteria, including Pseudomonas , and a lower relative abundance of Fusarium . Combining faba bean – wheat intercropping with N‐BC amendment mitigated Fusarium wilt while improving rhizosphere soil structure, nutrient status, and enzyme activity, reducing phenolic acid accumulation, and reshaping microbial composition. These findings support a soil‐health‐based strategy for sustainable continuous cropping management.