Growth and Medical Constituents of Saururus chinensis Baill as Affected by Different Amounts of Nitrogen Fertilizer Application

This study was conducted to investigate the selected chemical properties of soils in Saururus chinensis Baill (Chinese lizard's tail) cultivation fields to provide optimal fertilizer application rates and to examine the growth and phar- maco-consitituents of Saururus chinensis Baill as influenced by different amounts of nitrogen (N) fertilizer applications. Based on the results of selected soil chemical properties in 37 cultivation sites of the plant, soil pH, organic matter content, and exchangeable K + concentration were lower than optimal values for cultivating general medicinal crops even though rel- atively high standard deviations were found in some of the values. At the harvesting stage of the plant aerial parts, soil pH, electrical conductivity (EC), available P2O5, and exchangeable Ca 2+ , Mg 2+ , Na + decreased as comparing with those before transplanting the plant, whereas the concentration of exchangeable K + increased in the plot treated with N 100% and com- post. Fresh weight of the plant aerial parts were highest, 492.5 ㎏/10, in the N 100% treatment plot. Correlation equation between N levels treated (X) and yield of the plant aerial parts (Y) presented as Y = �2.1609X 2 + 30.082X + 344.12 (R 2 = 0.7113) and the optimal rate of N fertilizer application for the plant was 6.6 ㎏/10a. Carbon concentrations in the plant were not different among the different N levels applied. N and K concentrations in the plant were highest in the plot of N 100% with compost applications, the highest P concentration was in N 100% plot, and the highest Ca and S concentrations were in N 200% plot. Quercetin and quercitrin were highest in the N 150% plot and tannin was highest in N 100% or N 100% with compost application plot.