Abstract:To explore the effects of different biogas slurry concentrations and application methods on growth, physiological characteristic indexes and component content of Astragalus membranaceus var. mongholicus (Bge.) Hsiao, we potted 1yearold A.membranaceus var. mongholicus (Bge.) Hsiao seedlings, set four biogas slurry concentrations (0%, 50%, 80% and 100%), one chemical fertilizer concentration (the concentration is same as 50% biogas slurry concentration). The experimental results showed: (1) using base fertilizer and base fertilizer+spray as the 2 kinds of application methods, the growth index of A. membranaceus var. mongholicus (Bge.) Hsiao increased firstly and then decreased with the increase of biogas slurry concentrations, the growth of single plant was based on base fertilizer+spraying, which showed a trend of decreasing firstly and then increasing, the above indicators were higher with chemical fertilizer. (2) The contents of chlorophyll, proline and soluble sugar firstly increased and then decreased with the increase of biogas slurry concentrations, the indicators of chlorophyll, osmotic adjustment substance were higher with 80% biogas slurry fertilizer (P<0.05). (3) Using base fertilizer as the application method, the activity of SOD decreased firstly, then increased and decreased finally. The activities of POD and CAT increased firstly, then decreased and increased eventually. Using base fertilizer and spray as the application method, all indicators of antioxidase activities showed a same trend of increasing firstly and then decreasing with the increase of the biogas slurry concentration, and the SOD value of 80% biogas slurry fertilizer treatment and the POD and CAT values of chemical fertilizer treatment were significantly higher than other treatments (P<0.05); the content of malondialdehyde (MDA) decreased firstly, then increased and decreased finally with the application of base fertilizer method, the application of base fertilizer + spraying increased firstly and then decreased, and the indicator was higher with 80% biogas slurry fertilizer (P<0.05). (4) The contents of astragaloside and calycosin7OβDglycosides increased firstly and then decreased with the increase of biogas slurry concentration compared with the two irrigation methods. As a whole, the contents of astragaloside and calycosin7OβDglycosides increased by 57.44% and 24.06% compared with the control, respectively. Compared with the same concentration of chemical fertilizer, the content of astragaloside in the biogas slurry treatment increased by 74.47%, while the content of calycosin7OβDglycosides decreased by 42.16%. These results indicated appropriate biogas slurry concentration and irrigation method can improve the growth and index component content of A. membranaceus var. mongholicus (Bge.) Hsiao seedling. The A.membranaceus var. mongholicus (Bge.) Hsiao seedling which treated with 80% biogas slurry fertilizer had better growth and higher quality.