Detailed Explanation of Licorice Planting, Cultivation Techniques and Management Key Points

Overview Licorice, also known as sweet grass root, red licorice, and powdered grass. It is the leguminous plant licorice Glycyrrhiza uralensis Fisch., with the root and rhizome used as medicine. It has the effects of clearing heat and detoxifying, moistening the lungs and stopping cough, and harmonizing various medicines; processed licorice has the effect of tonifying the spleen and boosting qi.

Plant characteristics: perennial herb, root thick and robust, cylindrical, sweet-tasting, outer bark brownish-red. Stem erect, slightly lignified in the lower part. Leaves alternate; odd-pinnate compound leaves, leaflets 7-17, ovate-elliptic, both surfaces covered with glands and short hairs. Racemes axillary, flowers papilionaceous, pale purplish-red. Pods oblong, sometimes sickle-shaped or curved in a ring, densely covered with brown bristle-like glandular hairs. Seeds flat and round. Flowering period June-July, fruiting period July-September.

Growth habits

Licorice mostly grows in the northern temperate zone, in plains, mountainous areas or river valleys at an altitude of 0-200 m. Wild licorice is accompanied by plants such as apocynum, Populus euphratica, reed, sand sagebrush and ephedra. The soil is mostly sandy soil. The soil pH should preferably be neutral or slightly alkaline; it grows poorly in acidic soil. Licorice prefers an ecological environment with sufficient light and a large diurnal temperature difference, and has the characteristics of being light-loving, drought-tolerant, heat-tolerant, salt-alkali-tolerant and cold-tolerant. The northwest, north and northeast regions of China are all suitable for planting licorice.

Cultivation management, harvesting and processing

1. Site selection and land preparation

Usually sandy soil that is fertile, loose in texture, well-drained and low in salinity and alkalinity is selected. Waterlogged low-lying areas and areas with a high groundwater table are not suitable for planting. Generally, deep ploughing of about 20 cm is carried out, and after ploughing the land is leveled and harrowed fine. Areas with heavy clay soil are not suitable for planting licorice.

2. Planting

Direct seeding of licorice. Seed treatment, physical method: coarse sand or a rice milling machine can be used to abrade the seed coat, making the seed coat rough and increasing water permeability. As a perennial herb, licorice can be sown in spring, summer or autumn. Both mechanical and manual sowing are possible, using drilling, with a sowing depth of 2-3 cm, and appropriate compaction after sowing.

Seedling raising and transplanting. Around mid-April, sow when the daily average temperature is stably above 5°C. Both mechanical and manual sowing are possible, using drilling, with a sowing depth of 2-3 cm and a row spacing of 30 cm. Compact appropriately after sowing. The sowing rate is about 20 kg per mu. Seedling raising and transplanting are generally carried out in the spring of the second year. When transplanting, open a furrow, place the licorice flat into the furrow, then cover with soil and compact. This is conducive to the growth and development of the rhizome and facilitates digging.

3. Field management of licorice

1. Thinning: if the sowing row spacing is 30 cm, then it is sufficient to keep a plant spacing of 18.5-20 cm when thinning.

2. Irrigation: around the emergence of seedlings, licorice should be kept frequently moist to facilitate emergence and seedling growth. The specific irrigation should depend on the soil type and salinity-alkalinity: for sandy soil with no salinity-alkalinity or slight salinity-alkalinity, water can be applied immediately after sowing; for heavy clay soil or soil with heavier salinity-alkalinity, water should be applied before sowing, sowing should be done while seizing the soil moisture, and no water should be applied after sowing, so as to avoid soil compaction and a rise in salinity-alkalinity. The key to cultivating licorice is preserving the seedlings; generally, once the plants have grown, they are no longer watered.

3. Cultivation and weeding: cultivation and weeding are generally carried out in the same year as seedling emergence, and weeds must be removed in time especially at the seedling stage. From the second year on, licorice roots begin to tiller, and weeds find it difficult to compete with them, so cultivation and weeding are no longer needed.

4. Fertilization: sufficient base fertilizer should be applied before sowing, preferably barnyard manure. In the sowing year, phosphate fertilizer can be applied as a top dressing in early spring, and before the winter freeze, 2000-2500 kg of organic fertilizer can be applied per mu as a top dressing. Licorice roots have root nodules and have nitrogen-fixing ability, so nitrogen fertilizer is generally not applied.

5. Pests and diseases and their control: in the rainy season, powdery mildew and rust are prone to occur, and Bordeaux mixture of 1:1:150 can be sprayed; in the dry season, red spiders are prone to occur, and 40% dimethoate emulsifiable concentrate at 1000-1500 times dilution can be sprayed for control. Among underground pests, cutworms bite and feed on the rhizome, and 0.5 kg of 90% trichlorfon technical material plus 50 kg of bait can be mixed into poisoned bait to trap and kill them.

4. Harvesting and processing

Dig in autumn from late September to early October, when the aboveground stems and leaves wither. Licorice roots are deep, so deep digging is required; the roots must not be broken off or the root bark damaged. After digging out, remove the residual stems and soil; do not wash with water. While fresh, separate the main roots from the lateral roots, remove the rhizome head, fibrous roots and branch forks, sun-dry until half dry, tie into small bundles, then sun-dry until completely dry. It can also be dug in spring before the licorice stems and leaves emerge, but the quality of autumn digging is better.