Objective  To alleviate reductions in yield and quality caused by continuous cropping of patchouli (Pogostemon cablin), and explore the application potential of effective microorganisms (EM) in continuous cropping of patchouli.

Method  We designed five treatment groups (EM were counted by volume faction): Garden soil (control soil), continuous cropping soil, continuous cropping soil + 0.1% EM, continuous cropping soil + 0.8% EM, and continuous cropping soil + 1.6% EM. Pot experiments were conducted to investigate the effects of EM addition on growth characteristics and soil microecology of patchouli cuttings.

Result  Compared with the treatment of only continuous cropping soil, the root length, plant height, fresh weight, root activity and chlorophyll content of treatment groups with EM addition were significantly higher, the numbers of soil bacteria and actinomycetes increased, the number of fungi decreased, and soil urease, sucrase and polyphenol oxidase activities increased significantly. The 0.8% EM treatment had the most significant effect on the growth characteristics and soil microecology of patchouli cutting seedlings, and plant height, fresh weight, root length, root activity and total chlorophyll content increased by 70.34%, 195.32%, 101.52%, 156.84% and 195.33% respectively. In the 0.8% EM treatment, the numbers of soil bacteria and actinomycetes peaked on the 40th day of cultivation, and soil urease, sucrase and polyphenol oxidase activities also peaked on the 40th day of cultivation, which were 81.46%, 54.26% and 137.90% higher than those in the treatment of only continuous cropping soil.

Conclusion  EM can effectively alleviate the problem of continuous cropping obstacles of patchouli, and can be used as a good additive in the continuous cropping of patchouli.