Influence of Soil Flooding with Organic Matters Amendment on Reducing the Root Rot Disease and Content of Ginsenosides in Ginseng Crops

Ginseng is mostly grown in Republic of Korea and China, and has been traditionally used as a medicinal plant for treating diseases including hypertension, diabetes mellitus, liver and kidney dysfunction and mental disorders. It is cultivated for three to six years. One of the most serious problems in ginseng cultivation is that, when ginseng is cultivated in a soil damaged by successive cropping, the root rot caused by Cylindrocarpon destructans disables replanting for the following decade. In this study, as a solution to soil sickness by continuous cropping, flooding treatment using organic matters (rice straw, cocopeat, bark) was applied to a paddy field from which ginseng was harvested for two years, and only rice straw was used for the non-treatment field. Regarding the prevalence of root rot according to the organic matter used for flooding treatment, in the rice straw group, the prevalence was reduced to 27.9% among 3-year ginseng and to 13.7% among 4-year ginseng, while, in the cocopeat group, it was reduced from 22.6% to 12.7% among 3-year ginseng. Also, in the bark group, it was reduced from 12.1% to 7.9% among 3-year ginseng. In the non-treatment group, the prevalence was high, 98.7% among 3-year ginseng and 100% in 4-year ginseng. The yield increased, in the rice straw group, from 626 kg/10a for 3-year ginseng to 825 kg/10a for 4-year ginseng, and, in the bark group, 531 kg/10a for 3-year ginseng to 791 kg/10a for 4-year ginseng, while, in the cocopeat group, it increased from 321 kg/10a for 3-year ginseng to 770 kg/10a for 4-year ginseng. Among ginsenoside components, Rg1, Rf, Re, and Rd decreased in 4-year ginseng compared to 3-year ginseng in all organic matter groups, while Rc+Rb2 increased in the 4-year ginseng compared to 3-year ginseng. The Rb1 content was similar between 3-year ginseng and 4-year ginseng.