Correlation analysis between continuous cropping obstacle of Gastrodia elata and Ilyonectria fungi and relieving strategy / 中国中药杂志

The continuous cropping obstacle of Gastrodia elata is outstanding, but its mechanism is still unclear. In this study, microbial changes in soils after G. elata planting were investigated to explore the mechanism correlated with continuous cropping obstacle. The changes of species and abundance of fungi and bacteria in soils planted with G. elata after 1, 2, and 3 years were compared. The pathogenic fungi that might cause continuous cropping diseases of G. elata were isolated. Finally, the prevention and control measures of soil-borne fungal diseases of G. elata were investigated with the rotation planting pattern of "G. elata-Phallus impudicus". The results showed that G. elata planting resulted in the decrease in bacterial and fungal community stability and the increase in harmful fungus species and abundance in soils. This change was most obvious in the second year after G. elata planting, and the soil microbial community structure could not return to the normal level even if it was left idle for another two years. After G. elata planting in soils, the most significant change was observed in Ilyonectria cyclaminicola. The richness of the Ilyonectria fungus in soils was significantly positively correlated with the incidence of G. elata diseases. When I. cyclaminicola was inoculated in the sterile soil, the rot rate of G. elata was also significantly increased. After planting one crop of G. elata and one to three crops of P. impudicus, the fungus community structure in soils gradually recovered, and the abundance of I. cyclaminicola decreased year by year. Furthermore, the disease rate of G. elata decreased. The results showed that the cultivation of G. elata made the Ilyonectria fungi the dominant flora in soils, and I. cyclaminicola served as the main pathogen of continuous cropping diseases of G. elata, which could be reduced by rotation planting with P. impudicus.

Progress in improvement of continuous monoculture cropping problem in Panax ginseng by controlling soil-borne disease management / 中国中药杂志

The continuous monoculture cropping problem severely has hindered the land resource of Panax ginseng cultivation and threatened the sustainable development of ginseng industry. There are comprehensive factors causing the continuous monoculture cropping problem, such as deterioration of soil physical and chemical properties, accumulation of allelochemical, increase of pesticide residue and heavy metal, imbalance of rhizospheric micro-ecosystem, and increase of soil-borne diseases. Among soil-borne disease was one of the key factors. More than 40 soil-borne diseases have been reported in the ginseng cultivation, especially, the diseases were more serious in the ginseng replanting land. Here main soil-borne diseases and their prevention way have been summarized, and we try to provide the effective improvement strategy of continuous monoculture cropping problem focusing on the disease control and offer reference for overcoming the ginseng continuous monoculture cropping problem.