Detailed Explanation of Key Techniques for High-Yield Cultivation of Licorice

Licorice, also known as sweet grass root, is a medicinal plant of the Fabaceae family. Its roots and rhizomes are used as medicine, and it has the effects of tonifying the spleen and boosting qi, clearing heat and detoxifying, moistening the lungs and stopping cough, and harmonizing all medicines. Licorice prefers a dry climate and tolerates severe cold. It is suitable for planting in sandy soil with deep soil layers, good drainage, a relatively low groundwater table, and rich calcium content. The soil should preferably be neutral or slightly alkaline. Waterlogged lowlands, land with a high groundwater table, and acidic soil are not suitable for planting.

Licorice is generally propagated by rhizomes. After harvesting licorice in autumn or spring, the thick roots are used as medicine, and fine rhizomes are selected as seed material, cut into small sections of 10--15 cm, each with 2--3 buds. In autumn, plow the soil deeply to 30--50 cm and apply sufficient base fertilizer, with 2500 kg of manure and 200 kg of superphosphate per mu. After plowing, harrow the soil level. Sow in the following spring, around the first ten days of April, open furrows at a row spacing of 30 cm and a furrow depth of about 10 cm, place the rhizomes flat in the furrows at a plant spacing of 10--15 cm, cover with soil, harrow level, press firm, water, and cover with film. Concentrated seedling raising with scattered transplanting, ridged cultivation, and mulching with straw or plastic film can also be used.

Before and after emergence, licorice should be kept constantly moist to facilitate emergence and seedling growth, and it should be watered promptly in dry weather. When the seedlings have grown 2--3 true leaves, thinning should be carried out. After final thinning, the plant spacing is 10--13 cm. Weeds should be removed promptly during the seedling stage. After the plants grow larger, rhizomes may be exposed above the ground, so soil should be hilled up appropriately. Large clumps of grass can be pulled out, and hoeing is also advisable. In winter, 2000--2500 kg of farmyard manure can be applied per mu as a topdressing. After two years of cultivation, the rhizomes of licorice will have spread throughout the entire plot, so no special management is needed.

Licorice has diseases such as rust, brown spot, and powdery mildew, and pests such as aphids and red spiders. For rust, use 0.30--0.40 degree lime sulfur mixture or a 400-fold solution of 97% nabam for control; for brown spot, use 1:1:100--160 Bordeaux mixture or a 1500--2000-fold solution of 70% thiophanate-methyl wettable powder for control; for powdery mildew, use 0.20--0.30 degree lime sulfur mixture for control; for aphids, use a 1000--2000-fold solution of 50% fenitrothion or a 1500--2000-fold solution of 40% dimethoate emulsifiable concentrate for control; for red spiders, spray with a 1500--2000-fold solution of 20% dicofol or a 500--1000-fold solution of 25% chlordimeform aqueous solution, once a week for several consecutive times.

Licorice can be harvested 2--3 years after planting, from late September to early October, when the aboveground stems and leaves wither. Licorice roots are deep, so deep digging is necessary. Do not dig them broken or damage the root bark. After digging them out, remove the remaining stems and soil. Do not wash with water. While fresh, separate the main roots and lateral roots, sun-dry until half dry, tie into small bundles, then sun-dry until fully dry for medicinal use.