Effect of N Application on the Yield and Quality of Chinese Chieves

For finding the relation between N and yield and quanlity,adopting the ways of experiment in filed and laboratory.The results showed that the relation of the yield and N application of Chinese chieves was parabola in the commencement of plastic film covered shed;It are positive correlation in the period of nutrition root,but magrginal utility fall when the N application was greater than 225 kg/hm2.The content of Vc,corase fiber and soluble polysaccharides was negative correlation to N application in the commencement of plastic film covered shed,it is parabola in the period of nutrition root.The content of soluble protein was positive correlation to N application in two period.Effect of N application on the yield and quality of chinese chieves in the commencement of plastic film covered shed was more greater than in the period of nutrition root,then Chinese chieves'critical period of fertilizer requirement is the period of nutrition root.