Nitrogen nutrition in Glycyrrhiza uralensis Fisch

The effect of different nitrogen levels on G.uralensis was studied in 2002. The results show that before the dosage of nitrogen fertilization reaches 0.15 g/L, an increasing dosage of nitrogen fertilization will accelerate growth and physiological indicators. When the dosage is 0.15 g/L, almost all indicators reach their highest levels; when the dosage exceeds 0.15 g/L, the values of all the indicators begin to decline to different degrees. The net photosynthetic rate of G.uralensis has a significantly positive linear relation with biomass and yield. The nitrogen, phosphorus and potassium contents in G.uralensis leaves also have linear relations with height, root diameter, single plant weight and yield of G.uralensis. Increasing nitrogen levels has no obvious effect on chlorophyll fluorescence parameters, but can improve glycyrrhizinic acid content.