Detailed Explanation of Licorice Cultivation Techniques and Methods
Licorice is a perennial herbaceous plant of the Fabaceae family, and the medicinal parts are the root and rhizome. 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 acute conditions, moistens the lungs, removes toxins, and harmonizes all medicines, making it an indispensable herb in many traditional Chinese medicine prescriptions.
(1) Site selection and land preparation. Licorice prefers arid climates and is suited to sandy loam with deep soil layers and a low groundwater table, which can achieve high starch content, less fiber, strong sweetness, and good quality. In autumn, deep plough to about 30 cm, and together with deep ploughing apply 4000-5000 kg of high-quality farmyard manure per mu, 20 kg of urea, and 50 kg of calcium superphosphate, then harrow and level, and wait until the following year for planting.
(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, roughly between March and April. If spring drought is severe, sowing can be done after summer rain. In late autumn and early winter, sowing can be done before the soil freezes, so that the seeds overwinter dormant in the soil and germinate and emerge after temperatures rise the following year. Before sowing, the seeds should be mechanically abraded 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 level 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 the other methods the same as above.
Rhizome propagation. It is best to dig up 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 planting, 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, then cover with soil and press down. Use 75-100 kg of planting stock per mu.
(3) Field management. When the seedlings have grown 3 true leaves, thin them once to spread the seedlings out. When they have 5 true leaves, final thinning is done, with a plant spacing of about 15 cm. During the growing period, loosen the soil and weed in a timely manner. 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 in combination 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 the soil to facilitate overwintering.
(4) Harvesting. Seed-propagated plants are harvested after 3-4 years, and rhizome-propagated plants after 2-3 years. Digging can be done in late autumn and early winter as well as before spring sprouting. Those dug in autumn are best, with high glycyrrhizic acid content and firm texture. After digging out licorice, remove the soil thoroughly, 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 completely dry, and it can be stored @#@136@#@.