Effects of different irrigation and fertilizer coupling on the physiological characteristics and bioactive components of licorice in Xinjiang arid area

Licorice ( Glycyrrhiza uralensis Fisch .) is an important medicinal plant with bioactive compounds. Efficient water and fertilizer coupling is critical for improving the physiological characteristics and bioactive components of licorice in arid regions. A four-year field experiment (2019–2022) was conducted in Xinjiang, China, to investigate the effects of different irrigation (W1: 2500 m³/ha, W2: 4000 m³/ha, W3: 5500 m³/ha, W4: 7000 m³/ha) and fertilization levels (F1: 305 kg/ha, F2: 610 kg/ha, F3: 915 kg/ha, F4: 1220 kg/ha) on licorice ( Glycyrrhiza uralensis Fisch.). Results showed significant interactive effects of irrigation and fertilization on photosynthetic traits, glycyrrhizic acid, flavonoid content, and root yield. Under the W2F2 treatment, glycyrrhizic acid and flavonoid content increased by 23.4 % and 20.1 %, respectively, while root biomass improved by 28.5 % compared to the W1F1 treatment. Photosynthetic rate also peaked at 13.87 μmol·m⁻²·s⁻¹ in the W2F2 group. Comprehensive evaluation determined that irrigation levels between 2500–4000 m³/ha and fertilization levels between 305–610 kg/ha are optimal for improving licorice productivity and quality under arid conditions. These findings provide a scientific basis for sustainable licorice cultivation in water-scarce environments. • Optimal irrigation (4000 m³/ha) and fertilization (610 kg/ha) increased root yield by 28.5 % and glycyrrhizic acid by 23.4 %. • Photosynthetic rate reached its peak (13.87 μmol·m⁻²·s⁻¹) under the W2F2 treatment. • Moderate water and fertilizer coupling provides a sustainable strategy for improving licorice quality and productivity in arid regions.