Effects of continuous cucumber cropping on crop quality and soil fungal community

Long-term continuous cropping is a common practice in facility vegetable production, which has an adverse effect on cucumber yield and quality. Soil fungi are of great significance for creating a normal soil ecological environment. However, the impact of continuous cropping on cucumber quality and soil fungal community has yet to be understood. In this study, we evaluated the effects of continuous cropping on cucumber using high-throughput sequencing technology. The results showed that the extension of continuous cropping would increase nitrate and total acidity of cucumber, while the contents of vitamin C (VC), soluble sugar, and protein were decreased. The increase of continuous cropping duration also reduced the fungal diversity of the cucumber soil. For example, the activity of three dominant fungal phylums, Ascomycota , Aphelidiomycota , and Basidiomycota , decreased with the extension of planting years. The relative abundance of the two fungi species ( Remersonia_thermophila , Mortierella_oligospora ) was negatively correlated with the contents of available phosphorus and available potassium ( P