| Ginseng(Panax ginseng C.A.Mey) is a valuable medicinal plant and has played an important role in traditional Chinese medicine.It possesses high applied value and economic value.Because of ginseng discontinuous cropping, development model of deforestation for the ginseng cultivation has not only destroyed a large number of forest resources but also seriously hindered the development of the ginseng industry. As we know, Ginseng grows in slightly acidic soils and aluminum toxicity is the most important limiting factor of plant growth and crop yield in acidic soil, so based on physical and chemical properties of ginseng soil,This paper Studied the the relationship between Mutual transformation of aluminum species and ginseng discontinuous cropping (mainly ginseng red coating root disease),in order to effectively solve the problem of ginseng discontinuous cropping even to Provide foundational theoretical knowledge.This paper first investigated the physical and chemical properties of albic soil horizon and different albic ginseng soil. the results showed that pH of albic soil horizons and albic ginseng soil were lower, they were acid soils. the role of Albic continue to occur during albic soil formation, resulting in iron,aluminum leaching to deposition, so that the albic soil accumulated a large amount of soluble aluminum ions to acid soil.Albic ginseng soil was formed by mixing A layer and E layer of woodland albic soil in an appropriate proportion. Ginseng continuous cropping in Albic ginseng soil leaded to the deterioration of physical and chemical properties and increased soil acidity.Soil acidification is the most importantly essential chemical characteristics of albic ginseng soil, and acidification problem is the key factor of ginseng discontinuous cropping.On the other hand, application of Inorganic fertilizers promoted soil acidification, especially the large number of physiological acidic fertilizer.Because of albic ginseng soil containing a large number of alkali-hydrolyzable nitrogen,Nitrate nitrogen and exchangeable calcium and magnesium,the absorption of NH4+, nitrate nitrogen carrying on the soil nutrient ions (Ca,Mg) leaching washing,nitrification would result in ginseng soil acidification. After growed ginseng, albic ginseng soil had become deterioration of ecological environment.First of all,increasing ginseng soil acidification caused by ginseng continuous cropping not only promoted a large number of calcium and magnesium dissolution from soil mineral,but also provided a large number of exchangeable H+, Al3+ due to albic which caused calcium and magnesium leaching. Secondly, ginseng soil was under the plastic shelf all year round, as a result of higher pedosphere temperature, mass of nitrate nitrogen in ginseng soil with the water would gradually move and accumulate to the pedosphere. With the elongation of ginseng cultivation period, the accumulation of nitrate nitrogen increased significantly in pedosphere. due to plastic shelf, it was difficult to diffusion into the atmosphere for nitrate nitrogen,as these reasons, resulting in excess nitrate nitrogen occurred in pedosphere, which produced nitrogen toxicity for ginseng.The most important problems of acid soil were soil acidity and chemical properties and the role of aluminum which were associated with aluminum species and distribution in the acid soil. Albic ginseng soil was acidic owing to ginseng continous cropping,so this paper firstly extracted the different aluminum species with continuous-extraction in albic ginseng soil. results showed that there were amounts of active aluminum including exchangeble aluminum and monomeric hydroxy aluminum in albic soil,which was potential hazards to ginseng cultivation. in Albic ginseng soil, although contents of acidolysis inorganic aluminum and organically complexed aluminum had possessed vast majority of extractable aluminum total content,but with the elongation of ginseng cultivation period, there were no significant differences in content, these results showed that their contents is relatively stable in ginseng soil, which could be related to soil clay mineral composition, But their contents were slow upward trend in acidic conditions. The mainly activity aluminum species were exchangeble aluminum and relatively small amounts of monomeric hydroxy aluminum which were less of the total amount of extractable aluminum in ginseng soil. With elongation of ginseng cultivation period, ginseng Soil pH values decreased significantly to promote the weathering of soil clay minerals, which Leading to amorphous aluminum hydroxide (mainly Al (OH) 3), hydroxy-aluminum polymers and aluminosilicate gradually dissolved into ginseng Soil solution. Finally, contents of exchangeble aluminum and monomeric hydroxy aluminum were significantly increased,especially exchangeable aluminum. Therefore, essential quality of albic ginseng soil acidification was that the content of activity aluminum increased significantly, especially exchangeable aluminum. To confirm whether superabundantly activity aluminum in ginseng soil was harmful to the ginseng growth and the relationships between activity aluminum and ginseng's red coating root disease, aluminum content of healthy ginseng and diseased ginseng root tissues was determined In this study. The results showed that ginseng root tissue accumulated a great deal of aluminum because of the existence of superabundant Al3+ in Albic ginseng soil owing to ginseng continuous cropping causing soil acidification. In particular, Al content in ginseng periderm tissue was significantly higher than subcutaneous tissue, and increasesd with the elongation of ginseng cultivation period. aluminum accumulation content in ginseng root tissue significant increased owing to ginseng red coating root disease, especially aluminum content in diseased ginseng root Periderm tissue were significantly higher than that in healthy ginseng, that in diseased ginseng root subcutaneous tissue also slightly increased. And aluminum accumulation in Periderm tissue of diseased ginseng and healthy ginseng was significantly higher than that in subcutaneous tissue,which demonstrated that ginseng root periderm tissue was the main place of aluminum accumulation. On the other hand ,the assay results of ginseng root tissues showed that calcium and magnesium mainly accumulating in the ginseng root periderm tissue, which was significantly increased due to ginseng red coating root disease. The existence of superabundant Al3+ in albic ginseng soil may be the key factor for the occurrence of ginseng red coating root disease.
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