Cultivation Techniques and Field Management Methods for Licorice

Licorice is a perennial herbaceous plant of the Fabaceae family, and the medicinal parts are the roots and rhizomes. It contains 5-11% triterpenoid compounds, glycyrrhizin, followed by flavonoid compounds such as liquiritin, liquiritigenin, isoliquiritin, isoliquiritigenin, etc. It is neutral in nature and sweet in taste, harmonizes the middle and relieves urgency, moistens the lungs, detoxifies, and harmonizes various medicines, making it an indispensable herb in many traditional Chinese medicine prescriptions.

(1) Site selection and land preparation. Licorice prefers arid climates and is suitable for sandy loam soil with deep soil layers and a low groundwater table, which can achieve high starch content, low fiber, strong sweetness, and good quality. In autumn, deep plow about 30 cm, and together with deep plowing, apply 4000-5000 kg of high-quality farm manure per mu, 20 kg of urea, and 50 kg of calcium superphosphate, then harrow and level, and wait for planting the following year.

(2) Sowing and cultivation. Both licorice seeds and rhizomes can be used as propagation material.

Seed propagation. Sowing can be done in spring, summer, and autumn. In spring, sowing can be done after the soil thaws, around March to April. If spring drought is severe, sowing can be done after summer rain. In late autumn and early winter, sow before the soil freezes, so that the seeds dormancy over winter in the soil and germinate and emerge after temperatures rise the following year. Before sowing, the seeds should be mechanically ground to break the seed coat and ensure emergence. Drilling is mostly used for sowing, with row spacing of 30-50 cm and furrow depth of 3-5 cm. After sowing, harrow flat and cover with soil, with a sowing rate of 2.5-3 kg per mu. If the seed germination rate is low, increase the sowing rate according to the situation. When raising seedlings, the sowing rate can be increased to 5-6 kg, with other methods the same as above.

Rhizome propagation. It is advisable to dig licorice in spring and autumn, select young rhizomes about 1 cm in diameter, cut them into 15 cm segments, each with 1-2 axillary buds. When sowing, open furrows about 5 cm deep with a furrow spacing of 30-50 cm, place the rhizomes flat and aligned in the furrows with a segment spacing of 7-10 cm, cover with soil and press down. Use 75-100 kg of seed rhizomes per mu.

(3) Field management. When the seedlings grow 3 true leaves, thin them once to spread out the seedlings. When they have 5 true leaves, set the spacing at about 15 cm between plants. Loosen the soil and weed in a timely manner during the growing period. If heavy rain occurs, drain water promptly to prevent root rot. During the growing period, apply 30-50 kg/mu of nitrogen-phosphorus compound fertilizer together with rainfall. The main diseases and pests of licorice are powdery mildew, rust, aphids, and red spiders. Timely control can be carried out according to field occurrence. In autumn, appropriately earth up to facilitate overwintering.

(4) Harvesting. Seed propagation takes 3-4 years, and rhizome propagation takes 2-3 years to harvest. Digging can be done in late autumn and early winter as well as before sprouting in spring. Those dug in autumn are better, with high glycyrrhizic acid content and firm texture. After digging out licorice, remove the soil, remove the stem base, branches, and fibrous roots, cut into segments of appropriate length, sun-dry until half dry, tie into small bundles, then sun-dry until fully dry, and it can be stored @#@136@#@.