Abstract: Continuous cropping obstacles caused by long-term intensive cultivation has become an important bottleneck restricting the sustainable development of greenhouse vegetable industry. Increasing the knowledge available regarding the soil mechanisms behind continuous cropping obstacles is beneficial to develop the effective approaches to overcome this difficult problem present in intensive greenhouse vegetable production. Here,based on a continuous greenhouse cucumber cropping system located at North Henan Province of China,we evaluated the changes in soil fungal abundance and community structure with increasing cucumber cultivation history(the duration from 1 to 20 years with the interval of 5 years per treatment)through Real-time PCR and high-throughput sequencing. Continuous cropping of greenhouse cucumber significantly altered soil fungal abundance. In brief,fungal abundance initially increased and then decreased as increasing greenhouse cultivation history,and the peak occurred at the tenth year after continuous cropping of greenhouse cucumber. The tendency of the ratio of soil fungal to bacterial abundance with increasing greenhouse cultivation history was in line with soil fungal abundance. High-throughput sequencing revealed that the β diversity rather than α diversity of soil fungal community was obviously altered by continuous cropping of greenhouse cucumber. Increasing greenhouse cucumber cultivation history lowered the numbers of unique OTU in fungal community. At phylum level,Ascomycota dominated soil fungal community,and its average relative abundance was insensitive to continuous cropping of greenhouse cucumber. At order level,Microascales,Pezizales,Norank_p_Ascomycota and Sordariales together dominated fungal community. At genus level, Pseudallescheria, Lasiobolidium, Ochroconis and Chaetomium were the predominant members in fungal community. Continuous cropping of greenhouse cucumber significantly changed average relative abundances of these dominant community members. Meanwhile,most of these dominant community members significantly correlated to soil physicochemical variables. RDA analysis indicated that soil nitrate and available potassium and organic mater contents were the most important contributors to the alteration of soil fungal community structure. In conclusion,the results demonstrated soil fungal abundance and community structure as affected by continuous cropping of greenhouse cucumber.

Key words: Cucumber, Continuous cropping, Fungi abundance, Community structure

CLC Number: 

• S642.2

• S154.3