Crop rotation patterns affect the growth, soil properties, and rhizosphere microbiome of cut chrysanthemums

Continuous cropping obstacles in cut chrysanthemum, which are characterized by soil nutrient imbalance, reduced enzyme activities, and disrupted rhizosphere microbial communities, restrict the development of its industry. This study investigated the regulatory effects of crop rotation on soil properties and microbial communities, and compared the mitigation efficiency of different rotation patterns.

At 60 days of growth, cut chrysanthemums under crop rotation systems exhibited significant increases in stem diameter, as well as fresh and dry weights of both aboveground and underground biomass, compared to continuous cropping. Rotation significantly increased soil total nitrogen, hydrolyzable nitrogen, and available phosphorus, with cabbage rotation exhibiting the most prominent phosphorus accumulation effect. The activities of soil catalase, alkaline phosphatase, and sucrase were higher in rotation groups, whereas the activity of urease decreased with successive planting cycles. Bacterial richness increased with planting cycles, while fungal diversity declined. Notably, rotation reduced the relative abundance of pathogenic Fusarium by 17.1-28.1%. Multivariate analyses indicated that soil nitrogen and phosphorus were closely correlated with bacterial community structure, while phosphorus was the most influential factor on fungal communities. Critically, the two crop rotation systems exhibited distinct mechanisms: maize primarily exerts regulatory effects on soil microbial community structure and enzyme activities, while cabbage focuses on optimizing soil nutrient element status.

Crop rotation with maize or cabbage alleviates continuous cropping obstacles by improving soil nutrient status, enhancing enzyme activities, and optimizing rhizosphere microbial communities. Maize rotation excels in regulating soil enzyme activities and bacterial communities, whereas cabbage rotation is more effective in promoting plant biomass during the vegetative growth stage, accumulating soil phosphorus, and inhibiting pathogenic fungi. This study provides a theoretical basis for sustainable cut chrysanthemum production via rotation management strategies designed to enhance soil microbial and physicochemical properties.