Studies On Influencing Factors Of Continuous Cropping Obstacle And Soil Improvement Techniques Of Ginseng

With the development of ginseng industry in recent years, the medical and economic value of ginseng has aroused people's wide attention. However, the continuous cropping obstacle of ginseng has been a difficult problem in the world. At present, the main way of ginseng cultivation in our country is to cut down the forest to grow ginseng. With the rapid expansion of ginseng cultivation area, large area of forest ecological environment has been destroyed, causing serious soil erosion. Therefore, the area of new forest land has significantly reduced by the country, and ginseng was facing a grim situation without land.In order to solve the problem of sustainable development of ginseng planting industry, the abandoned ginseng soil improvement system was established based on soil physical and chemical properties, allelochemical substances and microbial ecology.In this study, three aspects including soil nutrients, chemical substances and microorganisms were studied. The analysis of soil nutrient content and chemical species in different years were carried out, and the content of improved index was determined. The mechanism of continuous cropping obstacle and its improvement effect were discussed. In order to improve the ginseng soil improvement technology system, the efficient cellulose degrading strains were screened out from the branches of trees and weeds in the straw, and the strain was identified by molecular biology method.The results showed that with the increase of the number of years, the soil nutrient content of ginseng decreased in different degrees, and the trend of soil acidification were appeared. With the increase of soil depth, soil nutrient content changed at different levels.The nutrient content of the improved area was higher than that in the control area. With the increase of the planting years, allelochemicals species exudates from ginseng roots were increased. These allelochemicals could destroy the soil environment of ginseng rhizosphere, changing their own metabolic mechanism of ginseng, and then damaged the normal growth of ginseng. Compared with the control area, the species of of the improved land were significantly reduced, and the improvement effect was significant.Three strains of the cellulose degrading strains of high activity were selected, which were bacteria strain32, actinomycetes strain 24 and fungi strain 10. Combined with the homology and the phylogenetic tree analysis, these three strains were initially identified as Novosphingobium,Streptornyces fradiae and Aspergillus terreus.In summary, combined with the analysis of ginseng soil nutrients, allelochemicals and microbial analysis, this study discussed the reasons of ginseng continuous cropping obstacle and the effectiveness of improvement, to provide a theoretical basis for producting the ecological organic biological fertilizer and improving ginseng soil improvement technology system, and finally to solve the problem of ginseng continuous cropping obstacle in an all-round way.