Relationship between the genesis of ginseng rust spots and soil ecological conditions
人参红皮病与土壤生态条件的关系

This paper deals with the ecological relationship between the condition of Ginseng rust spots,the reducing substances in the bed soil and the epidermis iron forms of Ginseng roots within the albic soil region of Jilin lava platform.The results showed that the concentrtion of reducing substances varied in different relief units.The active organic matter was markedly related to the illness index and become the major factor in the genesis of Ginseng rust spots.The enrichment of iron played the first important role in the epidermises of Ginseng roots.The epidermis iron was mainly composed of the organic complexing matter including active ferrous and ferric forms,and non active ferric forms,and they were transformed into each other with the change of soil moisture and temperature regime.The Fe o/Fe d was related to the active organic matter,that implied that amorphous iron in the soil might be the major source of Ginseng epidermis iron.The capacity of air filled pores was higher and the capacity of water holding pores also higher in the bed soil.It suggested that the oxidation reduction process in the soil to be tested happened at the same time,and it was of important significance for the transformation of iron in the bed soil.