Abstract: In order to provide the seedling substrates for cultivating high-quality seedlings to promote the production of transplanted-Astragalus membranaceus var. mongholicus （AMM）, six organic compound substrates were prepared by using vinasse as the main material supplemented with cow dung and biogas residues in this study. Their physicochemical properties and the content of alkaline nitrogen, available phosphorus and available potassium were measured. The organic compound substrates F2 （vinasse-cow dung 60-20） and Z2 （vinasse-biogas residue 60-20） were selected by analyzing the influence of auxiliary materials on the substrate properties via PLS-DA model and assessing the fertilization efficiency of each compound substrate via fuzzy evaluation method. Then, substrates F2 and Z2 were mixed with soil at the ratio of 3∶7 to make seedling substrate, respectively; and their application potentials were evaluated by seed germination and seedling growth test. The results showed that the physicochemical properties of each organic compound substrate could meet the requirements of conventional substrates, and the substrates F2 and Z2 had the higher evaluation coefficients of fertilization efficiency in the cow dung group and biogas residue group respectively. Among the mixed seedling substrates, the “F2+soil” group had the highest seed germination rate, and the germination potential and germination index were significantly higher than the “Z2+soil” and control groups; the whole plant length, height and fresh weight of seedlings were obviously superior to those of the seedlings in the other two groups. In sum, the organic compound substrate F2 had good performances, and the seedling substrate obtained by mixing F2 and soil could be used to cultivate high quality AMM seedlings and had good application potential.

Key words: seedling substrate, Astragalus membranaceus var. mongholicus, vinasse, germination and seedling growth