Analysis of the Microbial Communities and Populations in Soils with Continuous Cropping of Curcuma wenyujin and Fumigation

Abstract

【Objective】The study was conducted to clarify the microbial community structure in soil with continuous cropping of Curcuma wenyujin and fumigation treatment, aiming to lay a foundation for alleviating continuous cropping obstacles in C. wenyujin cultivation.【Method】The soil under a continuous cropping of C. wenyujin for 3 years was selected and fumigated with dazomet one month before planting C. wenyujin. After 7-month cultivation of C. wenyujin, we collected soil samples from three types of plots: continuous cropping, fumigated and uncultivated. Total soil DNA was extracted, and the population and diversity of microbial communities (fungi and bacteria) were analyzed by using PacBio Sequel thirdgeneration sequencing.【Result】The results showed that C. wenyujin plants in the fumigated soil exhibited good growth and minimal disease incidence, while those in the continuous cropping soil had poor growth and severe seedling death. Analysis of bacterial communities at the phylum level revealed that the abundance of AD3, TK10 and WPS-2 decreased in rhizosphere soil after continuous cropping compared with those in uncultivated soil. Fumigation of continuous cropping soil increased the abundance of beneficial bacteria with biocontrol functions such as Bacillus and Sphingomonas. Among the three soil types, 5 fungal phyla were abundant, including Ascomycota, Basidiomycota, Chytridiomycota, Mortierellomycota, and unclassified_k_ Fungi. Ascomycota had the lowest abundance in uncultivated C. wenyujin soil, but continuous cropping significantly increased its abundance, while Basidiomycota showed a significant decrease. Several beneficial fungal genera, including Chaetomium, Penicillium, Aspergillus, Myrothecium, Thielavia, Humicola, Rhizophlyctis, Microdochium, Ramicandelaber, Albifi mbria, Curvularia, Gigaspora, Nigrospora, Neocosmospora, Talaromyces, Roussoella, Rhytidhysteron, Boothiomyces, Apiotrichum, Ochroconis, Saitozyma, Trichosporon and Phoma, had higher abundance in fumigated soil than that in continuous cropping soil. In contrast, continuous cropping soil had a higher accumulation of pathogenic microorganisms.【Conclusion】Continuous cropping of C. wenyujin leads to the accumulation of harmful soil microorganism, resulting in continuous cropping obstacles. Fumigation with dazomet can reduce the number of soil-borne pathogens and increase the abundance of beneficial microbial populations, thereby mitigating continuous cropping obstacles in C. wenyujin cultivation.

Keywords

• curcuma wenyujin
• continuous cropping
• dazomet
• fumigation
• soil microorganism
• diversity analysis