Accumulative Rule Of Nitrogen,Phosphorusand Potassium Absorption And Its Relationship Withquality Of Artemisia

The medicinal part of Artemisia argyi Lévl.et Vant is the dry leaves of the Artemisia,which is a perennial herb with a long medicinal history use and can be harvested 2 to 3 times a year.Artemisia is cultivated on a large scale,but its harvesting conditions are mainly based on experience,which is not conducive to the control of its yield and quality.In this study,the research object,Artemisia was explored with field experiment and laboratory analysis,researched on the growth and development characteristics of Artemisia in different growth periods and harvest stubble periods,the nutrient absorption characteristics of nitrogen,phosphorus and potassium,as well as the content and yield of effective medicinal components.Finally,the rule of fertilizer demand during the growth period of Artemisia was summarized and the suitable harvest time of higher quality Artemisia was found,which provided theoretical basis for the cultivation management,high yield and good quality of Artemisia of Yangling area.The main conclusions of the experiment are as follows:During different growth stages and harvest stubble stages,the distribution of N,P and K in different organs of Artemisia was different,and the order was as follows:leaves>roots>stem.At different growth stages,N,P and K were preferentially distributed in roots,stem and leaves,respectively.There was no significant correlation among the distribution of three elements in Artemisia,while a significant correlation between the distribution of N-P elements in roots and stems.At different harvest stubble stages,N element was preferentially distributed in stem of the first stubble,roots of the second stubble and leaves of the third stubble,while P element was in roots and K element was in leaves.P-K in the roots was negatively correlated to some extent,but N-P in stem and leaves was significant positive correlation.All of these showed that Artemisia argyi were sensitive to the N,P,K nutrient changes,and could be important parts to guide the fertilization of Artemisia;and the stubble period had a great effect on the distribution of N elements,but no significant effect on P and K elements.Except root length and diameter,different growing stages and stubble stages can significantly affect the plant height,stem diameter,leaf length and other physiological indexes of Artemisia,while the yield of Artemisia was not significantly affected by the stubble stage.The discount ratio was 2.78,and the moxa yield rate was 15.47%.At different growth stages,the chlorophyll,soluble protein and soluble sugar of Artemisia decreased month by month.At different harvest stubble stages,the highest concentration of chlorophyll was in the second crop of July,the soluble protein was in the third crop of November,the soluble sugar was in the first crop of May,total flavonoids was in the first crop of May,and total terpenoids and eucalyptol was in the third crop in November.These results suggested that the harvest stubble period had significant effects on the growth,physiology and effective components of Artemisia.Different growing stages and harvest stubble stages have significant effects on soil enzyme activity in root system of Artemisia,but no effects on soil microbial.The total contribution rate of four principal components with eigenvalues greater than 1 was 88.607%,which showed that the active components,soil enzyme activities and soil microorganisms of Artemisia contributed to the quality evaluation of Artemisia at different growth stages and the harvest stages:the results of the first two principal components indicated that the active components and soil enzyme activities of Artemisia had a certain contribution to the quality evaluation;The third principal component indicated that catalase and fungi had a certain excellence in the quality evaluation of Artemisia;and the fourth principal component indicated that the yield rate also had an excellent performance in the quality evaluation of Artemisia.Optimizing the harvest time of high quality and high yield Artemisia,the results were as follows:the yield of May 28 was 17635.5kg/hm~2,the content of eucalyptus oil was113.49mg/g,the moxa yield rate was 12.95%,and the discount ratio was 3.36;the yield of the second crop of July 28was 21200kg/hm~2,the content of eucalyptus oil was 107.39mg/g,the moxa yield rate was 14.45%,and the discount ratio was 3.46.