[Effects of nitrogen, phosphorus and potassium application on growth and active ingredient of Astragalus membranaceus].

Objective: To study the effects of fertilizers with the different proportional of nitrogen, phosphorus and potassium on growth and active ingredient of Astragalus membranaceus.

Method: Field experiment was conducted based on the D-saturation optimal design with three factors of nitrogen, phosphorus and potassium. The effects on growth and active ingredient of A. membranaceus were analyzed.

Result: Fertilization promoted the seedling growth and provided abundant supply of nutrition for growth of root, yield and accumulation of active ingredient at the later growth stage, and increased the accumulation of dry matter of stem-leaf and root system. The effect of nitrogen, phosphorus and potassium application on the total dry matter accumulation of A. membranaceus was as following: nitrogen > potassium > phosphorus; the effect on the stem-leaf dry matter accumulation was as following: nitrogen > phosphorus > potassium; the effect on the root dry matter accumulation was as following: nitrogen > potassium > phosphorus. Nitrogen, phosphorus and potassium fertilizer increased the root yield of A. membranaceus. Obviously, the effect on the root yield was as following: nitrogen > potassium > phosphorus. The application of different proportional with nitrogen, phosphorus and potassium increased the content of polysaccharide and astragaloside, but had no distinct effect on the content of total flavonoids. The effect on the content of polysaccharide was as following: potassium > phosphorus > nitrogen, but the effect on the conten,t of astragaloside was as following: nitrogen > potassium > phosphorus.

Conclusion: Nitrogen and potassium fertilizer application had more important effect on growth, yield and the contents of polysaccharide and astragaloside in A. membranaceus. During medicinal plants cultivation process, it should pay attention to the application of nitrogen fertilizer and potassium fertilizer and make balance application of nitrogen, phosphorus and potassium fertilizer.