Detailed Explanation of Key Points for Artificial Cultivation Techniques of Chinese Licorice

Licorice, also known as sweet root and dense grass, has 23 varieties worldwide. China is the country with the most licorice distribution, with 12 varieties. Ural licorice (i.e., Chinese licorice) is the most widely distributed, highest-yielding and best-quality licorice species among the six licorice species listed in the pharmacopoeia of China, and has long enjoyed a high reputation in the international market. Licorice is a perennial herbaceous plant of the Fabaceae family, and its roots and rhizomes have the effects in traditional Chinese medicine of harmonizing various medicines and neutralizing a hundred toxins. China has the sayings "nine out of ten prescriptions contain licorice" and "no prescription is complete without licorice," so it is called the king of Chinese herbal medicines. Market demand for licorice has been rising steadily, and relying on the past practice of digging up wild resources can no longer meet the need. The worldwide shortage of licorice has caused licorice prices to rise repeatedly, from 700 USD/ton in 1981 to the current 3000 USD/ton. Therefore, artificial cultivation of Ural licorice is imperative and has broad prospects. Land selection: Licorice has wide adaptability and does not have strict requirements for the cultivation environment. It can be cultivated in semi-arid and arid areas with an average temperature of 4°C~12°C and sunshine hours of more than 2600 hours. Choosing sandy or water-quality soil with deep soil layers, a pH value of 7~8, a groundwater level below two meters, and a soil salt content not exceeding 0.5% for planting can achieve the goals of high germination and seedling survival rates, fast growth, brightly colored roots and rhizomes with good quality, and high economic benefits. Barren retired farmland can also grow licorice well.

Seed treatment

Licorice seed coats are hard and have poor water permeability, with a germination rate of only 4%~6%, so seed coat breaking treatment is needed. Treating seeds by rotating the central wheel of a vertical centrifugal rice mill to scratch the seed coat is simple, efficient, safe, low-cost, and gives a high germination rate; if the quantity of seeds is small, concentrated sulfuric acid can be used to corrode the seed coat, followed by rinsing with clean water, which can also break the coat. Timely sowing: Sowing can be done from April to August, with April to May being best. In areas without irrigation conditions and with strong spring sandstorms, sowing can be postponed until after June. Drilling is best, with a row spacing of 30 cm and a sowing depth of 2 cm~3 cm, deeper in irrigated land and shallower in clay land. For small-area sowing, broadcasting and covering with soil can be used, or a hoe can be used to open furrows for sowing. Planting methods: The main planting methods for licorice are direct sowing and seedling transplanting.

1. Direct sowing: If the seeds are clean and well treated, the soil texture is sandy or sandy loam, and the soil moisture is good, the sowing rate is 2 kg per 667 sq m (1 mu). If the seeds are not well treated, the insect infestation rate is high, and the soil texture is heavy clay or has high saline-alkali content, the sowing rate per 667 sq m should be increased to 2.5 kg~3 kg. Keep 20000~25000 plants per 667 sq m, and the planting specification is preferably 30 cm x 10 cm.

2. Seedling transplanting: Choose plots with irrigation conditions and loam or sandy loam soil texture. Apply more than 4000 kg of farmyard manure and 40 kg~50 kg of diammonium phosphate per 667 sq m, use treated high-quality seeds, keep 80000 seedlings per 667 sq m, and more than 60000 transplanted seedlings. After one year of cultivation, when the root crown thickness of the seedlings reaches 1 cm and the length reaches 40 cm, they can leave the nursery. Before the land freezes that year or after thawing the next year, dig out the seedlings, and never bruise the root crown. Dig and select at the same time, select seedlings with a stem diameter (referring to the part 1 cm~2 cm below the root crown) of 0.8 cm~1 cm and a length of 30 cm~40 cm, tie them into bundles, and cut off the excess length. Seedlings dug out in late autumn should be heeled in in a sheltered, sunny place with suitable temperature and humidity. Seedlings dug out in spring can be planted while digging. Seedlings with insufficient thickness and length can be planted in another selected plot. Choose fertile land convenient for irrigation, apply sufficient farmyard manure and diammonium phosphate, and transplant in early April. According to a furrow spacing of 18~20 cm, first use manual labor or machinery to open transplanting furrows 30 cm~40 cm wide and 8 cm~10 cm deep, place the prepared licorice seedlings horizontally in the furrows at a plant spacing of 8 cm~10 cm, then cover with soil, and transplant 8000~10000 plants per 667 sq m. Field management: Directly sown licorice seedlings grow slowly in the first year and are easily affected by weeds, so cultivation and weeding must be strengthened. Weed once each at the 3~4 leaf stage and when the plant height is 15 cm. In the second and third years, according to weed and soil conditions, loosen the soil and weed 2~3 times each year. Irrigate 2~3 times according to soil moisture. After licorice transplanting, irrigate immediately, and afterward irrigate promptly, apply chemical fertilizer, and pull weeds according to seedling emergence and weed growth. To prevent bruising the horizontally buried seedlings, never loosen the soil.

Pest and disease control

1. Licorice mealybug: The licorice mealybug is an important pest affecting licorice growth. Its damaging part is the roots 5 cm~10 cm below the soil surface, where nymphs suck licorice sap, causing the aboveground part to weaken and even the whole plant to dry up and die. The control method is to spray the roots with 40% amiton emulsion at 1000 times dilution during the nymph hatching period (late March to early April), and spray the ground with 50% phoxim emulsion at 800 times dilution or 10% Kejieling at 1000 times dilution during the adult emergence peak (early to mid-August), to reduce the insect population density the following year.

2. Rust disease: For summer spore diseased plants, during the early spring bud break period, use 25% triadimefon emulsion at 0.17 kg per 667 sq m (1 mu) or agricultural antibiotic 120 aqueous solution at 0.8 kg per 667 sq m, dilute with water, open furrows, and irrigate the roots. A 400-times dilution of 97% dithianon sodium can also be sprayed on the roots of diseased plants. If the area is small or only sporadic occurrences happen, the diseased plants can be gathered and the stems and leaves burned. Harvesting: For directly sown licorice, the best digging period is at 3~4 years of age, and the digging time is preferably March to April. Generally, the yield per 667 sq m is 300 kg~500 kg (fresh goods). Seedling-transplanted licorice grows fast, and digging in the second year is best, with fresh grass yield per 667 sq m reaching 600~1000 kg.