Long-term garlic‒maize rotation maintains the stable garlic rhizosphere microecology.

Background: Crop rotation is a sophisticated agricultural practice that can modify the demographic structure and abundance of microorganisms in the soil, stimulate the growth and proliferation of beneficial microorganisms, and inhibit the development of harmful microorganisms. The stability of the rhizosphere microbiome is crucial for maintaining both soil ecosystem vitality and crop prosperity. However, the effects of extended garlic‒maize rotation on the physicochemical characteristics of garlic rhizosphere soil and the stability of its microbiome remain unclear. To investigate this phenomenon, soil samples from the garlic rhizosphere were collected across four different lengths of rotation in a garlic-maize rotation.

Results: There were notable positive associations between the total nitrogen and total phosphorus contents in the soil and the duration of rotation. Prolonged rotation could increase the maintenance of microbiome α diversity. The number of years of rotation and the soil organic carbon (SOC) content emerged as principal determinants impacting the evolution of the bacterial community structure, with the SOC content playing a pivotal role in sculpting the species diversity within the garlic rhizosphere bacterial community. Additionally, SOC remains predominant in shaping the root-associated bacterial community's β-nearest taxon index. However, these factors do not have a notable effect on the fungal community inhabiting the garlic rhizosphere. In comparison with monoculture, rotation can amplify the interconnectivity and intricacy of microbial ecological networks. Long-term rotation can further maintain the stability of both microbial ecological networks and interactions between bacterial and fungal communities. It can enlist a plethora of beneficial Bacillus species microorganisms within the garlic rhizosphere to form a biological barricade that aids in safeguarding garlic against encroachment by the pathogenic fungus Fusarium oxysporum, consequently diminishing disease incidence. This study provides a theoretical foundation for the sustainable development of garlic through long-term crop rotation with maize.

Conclusions: Our research results indicate that long-term garlic‒maize rotation maintains stable garlic rhizosphere microecology. Our study provides compelling evidence for the role of long-term crop rotation in maintaining microbiota and community stability, emphasizing the importance of cultivating specific beneficial microorganisms to enhance rotation strategies for garlic farming, thereby promoting sustainability in agriculture.