Study on Changes of Soil Nutrient, Enzyme Activity and Structure of Microbial Community before and after Cropping Panax notoginseng

【Objective】The study was conducted to clarity the effects of Panax notoginseng continuous cropping on soil nutrient, enzyme activity and structure of microbial community and provide effective strategy for overcoming the obstacle to P. notoginseng continuous cropping.【Method】Combined with high-throughput sequencing, the influence of the extension of planting years on fungi and bacteria community of rhizosphere soil was analyzed.【Result】With the extension of plant years, the pH value and contents of total potassium, organic matter, available phosphorus and available potassium in soil were increased, while the contents of total nitrogen, total phosphorus, and alkali-hydrolytic nitrogen weredecreased. Except for alkaline phosphatase, the activities of urease, sucrase and polyphenol oxidase in soil were decreased obviously. High-throughput sequencing showed that, 15 fungi and 16 bacteria were detected and classified at the family level in soil before and after planting P. notoginseng. The Hygrocybe among the fungi from the soil（CK）before planting was the dominant strain, accounting for 55.17%, while the ratio was decreased to 0.37% after planting and the Fusarium was the dominant strain in the soil, accounting for 8.31%, which was 32 times higher than that before planting. The composition and population density of bacteria community in soil before and after planting P. notoginseng were obviously different, while the biocontrol bacteria like Pseudomonas and Streptomyces showed a decreasing trend with the extension of planting years. 【Conclusion】Generally, the microbial diversity in soil showed an increasing trend with the extension of planting years. The soil enzyme activity descended and the soil nutrition lose balance.