Ramie (Boehmeria nivea L. Gaud) suffers from long-term continuous cropping. Here, using Illumina high-throughput sequencing technology, we aimed to identify bacteria and fungi associated with continuous cropping in ramie fields in Yuanjiang, Xianning, Sichuan, and Jiangxi. The rarefaction results showed that Jiangxi had significantly lower bacterial α-diversity than that of the other areas. Firmicutes, Proteobacteria, and Acidobacteria were the dominant bacterial phyla, and Ascomycota, Basidiomycota, and Zygomycota were the dominant fungal phyla. In Jiangxi, Firmicutes accounted for 79.03% of all valid reads, which could have significant decreased microbial diversity and negative effects of continuous ramie cropping. We used traditional methods to examine soil nutrients. Sichuan had a relatively high pH and available P and K, but low total N; opposite findings were recorded in Jiangxi. The redundancy analysis revealed that the urease activity, PH, available K, and total N significantly correlated with bacterial community abundance, whereas only total N significantly correlated with fungal community abundance (p < 0.01). Overall, the effect of soil environmental factors on the bacterial diversity of continuous ramie cropping was greater than that on fungal diversity. In the future, we will focus on the effect of rhizosphere bacteria to solve the obstacle in continuous ramie cropping. In continuous cropping, the same or a similar species is planted continuously in the same field 1. Generally, long-term continuous cropping decreases crop yield and quality 2-4 , alters soil microbial communities 5,6 , affects soil biochemical properties 7,8 , and enriches soil-borne plant pathogens in soil 9,10. Soil microorganims are not only an important part of soil, but also the main drivers of soil nutrient cycling 11. Soil microorganisms play a crucial role in regulating the fertility of soil, health of plants, and cycling of C, N, and other nutrients 11,12. Previous studies have shown that long-term continuous cropping can alter soil microbial communities 13-15. In a continuous pea-cropping field, the soil microbial community was smaller, and the abundance of beneficial gram-positive bacteria and arbuscular mycorrhizal (AM) fungi was reduced 16. Similarly, Sun et al. found that in continuous cropping of banana, bacterial community diversity continuously decreased and bacterial community composition and structure were affected 8. Numerous studies have revealed that soil attributes are influenced by continuous cropping 17,18. In addition, environmental factors, such as soil pH, affect soil microbial communities 19,20. Wang et al. found that root exudate composition and soil pH affected soil microbial community in different plant growth stages 21. Thus, it is crucial to analyse the relationship between soil microbial community and environmental factors. However, only a few studies have focused on differences in different areas under continuous cropping with the same plant. Ramie, also known as "China grass, " is a perennial plant...
