Effects of nitrogen, phosphorus, and potassium fertilizer application on yield and output of the main extracts of Erigeron breviscapus

We studied the effects of different fertilizers nitrogen (N), phosphorus (P), and potassium (K) application rates on the growth index, yield, content, and output per unit area of three extracts (baicalin, total caffeic acid ester, and total flavone) of Erigeron breviscapus(Vant.) Hand.-Mazz.). Results showed that N and P application effectively increased the plant growth index. Yield of E. breviscapus increased with elevated N, P, and K application, with N application resulting in the greatest increase. Content of the three E. breviscapus extracts decreased with the application of N within a certain range, whereas application of P and K had no effect. Output per unit area of the three extracts were positively correlated with E. breviscapus yield. The application of N, P, and K fertilizers increased the yield of E. breviscapus and outputs of the three extracts. The highest output per unit area of the three extracts was achieved at N, P, and K application rates of 103.5, 126.0 and 112.5 kg/hm², respectively.