| Codonopsispilosula(Franch.)Nannf.,as a traditional tonic medicine of the same origin of medicine and food in China,has extensive application requirements in many fields.At present,the wild resources of Codonopsis pilosula are increasingly depleted,coupled with the immature cultivation experience and cultivation management technology,the yield and quality of Codonopsis pilosula are not guaranteed,and soil degradation and other problems have also occurred,which are not conducive to the sustainable development of Codonopsis pilosula.The effective exertion of the clinical curative effect of traditional Chinese medicine depends on the stable and controllable yield and quality of traditional Chinese medicine,and scientific and reasonable fertilization can largely regulate its yield and quality.Therefore,in this paper,the "3414" formula design of nitrogen,phosphorus and potassium was used for field experiments to study the effects of combined application of nitrogen,phosphorus and potassium on soil physical and chemical properties and enzyme activities;Dynamic changes;explore the absorption and distribution of nitrogen,phosphorus and potassium elements of Codonopsis pilosula;establish the corresponding fertilizer efficiency model and optimize fertilization based on field test results,aiming to provide a theoretical basis and technical reference for the realization of standardized cultivation of Codonopsis pilosula.The main findings are as follows:1.The combined application of nitrogen,phosphorus and potassium has certain improvement effect on soil physical and chemical properties and enzyme activity.Combined application has no significant effect on soil pH in the short term;most of the treatments will not increase soil salinity;N1P2K2,N2P0K2 and other treatments can increase the soil organic matter content to a certain extent;compared with the non-fertilized group,each combined application can significantly change the soil Enzyme activity,the N2P0K2 and other treatments in the early stage improve the soil invertase and phosphatase activities most significantly;the N3P2K2 and other treatments improve the soil urease activity in the middle stage,and the N2P2K1 and other treatments are the best in the middle and later stages.2.There are differences in the effects of nitrogen,phosphorus and potassium levels and combined application on the growth physiology,yield and quality of Codonopsis pilosula.The chlorophyll content of Codonopsis pilosula is high in the early stage of growth,at this time photosynthesis is the strongest,and the root growth is mainly carried out in the middle and late stages;under this test condition,each formula treatment can increase the yield,and the extracts can reach the pharmacopoeia standard(not less than 55%)),the highest extractables in the N0P2K2 treatment,the N2P2K2 treatment group had higher yield,root polysaccharide content,and Lobetyolin content,which were 2231.19 kg/hm2,32.66%,0.439 mg/g,respectively.The polysaccharide content of roots,stems and leaves(September 28)during the harvest period were:24.17～32.93%,4.7～11.1%,5.8～12.5%.3.Clarify the nutrition absorption and distribution rules of Codonopsis pilosula.(1)Nitrogen is mainly distributed in the leaves,the least in the roots,and the nitrogen content in the leaves continues to decrease in late July;the phosphorus content in the roots accumulates rapidly in the early stage,and the accumulation amount reaches the highest in late July,and is transferred to the aboveground part It reached its highest level at the end of September;the total potassium content in the roots and stems changed obviously in a"symmetrical" situation.On the whole,before the end of September,nutrients are mainly distributed in the leaves and stems of Codonopsis pilosula to ensure the needs of photosynthesis,which is beneficial to the accumulation of secondary metabolites.(2)Nitrogen application can significantly increase the nitrogen content in roots,stems and leaves,and its accumulation is related to the nitrogen application level and the growth stage of Codonopsis pilosula;No and Ni are more conducive to the accumulation of phosphorus in stems and leaves,and N2 can significantly accelerate the root Potassium accumulation.Phosphorus levels have no obvious rules for the accumulation of nitrogen in roots,stems and leaves;all levels of phosphorus can significantly increase the nitrogen content in the stem from late July to the end of September;in the middle growth period of Codonopsis pilosula,increasing the phosphorus application level is more beneficial to the phosphorus in the roots and stems Pi,P3 are more conducive to the accumulation of potassium in the root.Potassium level has no obvious effect on the nitrogen in roots and stems,but it will inhibit the accumulation of nitrogen in leaves;each potassium level promotes the accumulation of phosphorus in roots and leaves in the early stage of the growth of Codonopsis pilosula,while it is an inhibitory effect in the mid-term,after the end of August K2 and K3 are beneficial to increase the accumulation of phosphorus in leaves;increasing the level of potassium fertilizer application during the entire growth stage of Codonopsis pilosula has no significant effect on the accumulation of potassium in roots,stems and leaves.4.Propose the best fertilization amount and ratio of Codonopsis pilosula.Comprehensive analysis shows that the optimal combination of fertilization is:nitrogen application rate 146.02～153.70 kg/hm2,phosphorus application rate 57.50～69.60 kg/hm2,potassium application rate 29.28-38.34 kg/hm2,that is,the optimal fertilizer application ratio is 1:0.37～0.48:0.19～0.26,it is expected to reach the goal of yield greater than 2300 kg/hm2,polysaccharide content greater than 30%,and Lobetyolin content exceeding 0.35 mg/g. |
