Characteristics of soil microflora of Panax notoginseng in different continuous cropping years

We examined the soil microbial composition, total number, diversities and the characteristics of soil microflora of P. notoginseng in relation to increase in the continuous cropping years. The results showed that bacteria and fungi were the dominant groups in P. notoginseng microbial communities. In April (emergence period of P. notoginseng), the total number of soil microorganisms decreased initially but then increased. While, in August (flowering period), a reverse trend was seen. The soil microbial community changed from “fungal type” in April to a “bacterial type” in August. Microbial community composition in the new and 1-year cropped soil was similar; both had high microbial diversity “bacterial type”. whereas, the 2-years and 3-years continuous cropped soils were similar and had low microbial diversity “fungal type”. The soil microflora changed significantly with the seasons and cropping year and these changes may be the cause of P. notoginseng replant failure.