The Influence Of Ginseng Continuous Cropping On Soil Microbial Community Research

Ginseng(Panax ginseng C. A. Meyer), is usually used as adaptogenic, anti-aging etc. health tonic. It is mainly cultivated in China, Korea, and Japan etc. Asian countries. It has been regarded as one of the most important remedies in oriental medicine for more than1,000years. As herbaceous perennial plant, ginseng grows at least six years from sow to harvest. During the long growing process, soilborne diseases made severe threaten on the health of P. ginseng root. Rhizosphere and nonrhizosphere soils of one to six years ginseng were sampled from Dafang, Huangni and Wulidi in Jilin province.The genetic diversity of microbial community of the selected soils were characterized by culture-independent approaches, random amplified polymorphic DNA (RAPD). Results showed that, genetic diversity index of rhizosphere soil of ginseng that had not been transplanted was higher than the nonrhizosphere soil, while, after been transplanted, the diversity index of rhizosphere soil was lower than the nonrhizosphere soil. Genetic diversity index of the rhizosphere soil of3yr-ginseng was the highest one in both Dafang and Huangni.Metabolic function variance of microbe in the soil samples were characterized by community level physiological profiles (CLPP) using BiologTM EcoPlate. With the increasing of cultivating years, the carbon substrates metabolic activities of soil microbes-at three sites were increased and then dtscreased finally. AW CD value and utilization for six types of carbon source of the rihzosphere soil were higher than the corresponding nonrihzosphere soil. Except for the5yr-rhizosphere soil WLD2+3R sampled from Wulidi, the Shannon diversity indexes of the rihzosphere soils were higher than the nonrihzosphere soils. In principal component analysis of Dafang and Huangni, most of the rihzosphere soils gathered together, while most of the nonrihzosphere soils gathered. In Wulidi, soils with the same cultivating years gathered.We also analysed the microbial community structure of the rihzosphere soils and nonrihzosphere soils sampled from Dafang. We found that, Verrucomicrobia, Acidobacteria, Proteobacteria, Bacteroidetes, Acidobacteria, Firmicutes, Verruco-microbia were the dominants in the soils. With the increasing of cultivating years, plant disease preventive or plant growth promoting bacteria, such as Pseudomonas, Burkholderia, Bacillus, etc., tended to be rare.We made autotoxins solution, and sprayed on the new forest soil sampled from Fusong of Jilin Province. After three months, we examined the varience of microbial community using RAPD, results showed that the soils with the treatment of diisobutyl phthalate, diisobutyl succinate and the mixed autotoxins have lower genetic diversity index than the the CK and the soils treated with the other autotoxins. Cluster analysis showed that similarity coefficient of these soils is relatively high. In the metabolic function variance analysis of microbe in the soil samples characterized by community level physiological profiles (CLPP) using Bio logTM EcoPlate, we found that, the carbon substrates metabolic activity of control is higher than those treated with autotoxins. The AWCD value of soils that treated by diisobutyl phthalate, diisobutyl succinate and the mixed autotoxins were lower than those treated by the other autotoxins. In the principal component analysis, control was seperated with the soils treated by autoxins.