Faba bean-wheat intercropping controls the occurrence of faba bean Fusarium wilt by improving the microecological environment of rhizosphere soil

Abstract

Background

Fusarium wilt is a severe soil-borne disease that affects faba bean production. Faba bean-wheat intercropping is often used to control the occurrence of Fusarium wilt in faba bean.

Aims

To evaluate the effects of faba bean-wheat intercropping on the occurrence of faba bean Fusarium wilt and soil microecology.

Methods

We established two planting patterns, faba bean monocropping (M) and faba bean-wheat intercropping (I), to investigate Fusarium wilt occurrence and plant dry weight and assess changes in soil enzyme activities, microbial diversity, and community composition during different stages of disease onset.

Results

Intercropping effectively controlled faba bean Fusarium wilt at the three disease stages and increased the dry weight of faba bean plants. Intercropping promoted the activities of catalase (CAT), urease, sucrase, and acid phosphatase in the rhizosphere soil of faba bean at three disease stages. Bacterial and fungal diversity decreased with disease progression, and intercropping mitigated this trend. Compared with monocropping, intercropping increased the abundance of beneficial bacteria such as Proteobacteria, Actinobacteriota, Gemmatimonadota, Gemmatimonas, Conexibacter, and Sphingomonas, while reducing the abundance of pathogenic fungi such as Alternaria, Cladosporium, and Fusarium. Intercropping also increased the abundance of arbuscular mycorrhiza, soil saprophytes, and undefined saprophytes while decreasing the abundance of plant pathogens.

Conclusion

Faba bean-wheat intercropping enhanced soil enzyme activities, effective nutrient content, and alpha diversity indices of bacteria and fungi in the rhizosphere soil of faba bean, while promoting the abundance of beneficial bacteria, arbuscular mycorrhizal fungi, as well as both soil and undefined humus. Simultaneously, intercropping reduced the abundance of plant pathogens, facilitated nutrient cycling in the soil, provided sufficient nutrients for crop uptake, and mitigated the toxic effects of hydrogen peroxide on cells. Ultimately, this resulted in a reduced occurrence of Fusarium wilt.