Detailed Explanation of Mechanical Film-Mulching Cultivation Techniques for Licorice

Licorice is one of the main cash crops of the 222nd Regiment, with a sown area of more than 800 hectares. The licorice grown is Ural red-skin licorice, with bright color and excellent quality. The licorice rhizome is well developed and penetrates deep into the soil. It is suitable for dryland farming, tolerant of salt and alkali, strongly heliophilous, fond of calcium, afraid of waterlogging, and has very strong vitality.

I. Land Requirements

1. Site Selection

Cultivating licorice should choose flat terrain, loose texture, few weeds, high organic matter content, pH 5-8, and conveniently irrigated sandy soil, with loam being better. The previous crop is best as corn, @#@245@#@, barley, or melon fields; loess, black soil, and land with thicker humus can also be planted, but it is strictly forbidden to plant on sugar beet stubble, sunflower stubble, heavily saline-alkali land, or newly reclaimed wasteland.

2. Land Preparation

The licorice root system penetrates deep into the soil, so the plowing depth must not be less than 30 cm. In autumn, apply sufficient base fertilizer in combination with deep plowing, preferably well-decomposed barnyard manure. When preparing the land before sowing, treat the soil with 80-120 g of trifluralin per 667 sq m, then harrow and level with a spike-tooth harrow to a depth of 4-5 cm. The quality of land preparation must meet the six-character standard.

II. Variety Selection

The variety must suit the local soil, water, light, and heat conditions. Our regiment selects Ural licorice, whose rhizome has bright color, good quality, and relatively high economic benefit.

III. Mechanical Film-Mulching Sowing

1. Licorice can be sown in all three seasons of spring, summer, and autumn, with spring sowing being the best. Sowing uses a grain seeder for drilling with film mulching.

2. Sow from the end of March to mid-to-late April, with a plastic film width of 120 cm, using 1 film for 4 rows of drilling under the film. If harvesting after 2 years, the seeding rate is 3.5 kg per 667 sq m; for harvesting after 3 years, the seeding rate is 2-2.5 kg, with a sowing depth of 2.5-3 cm. Sowing must be equipped with a depth limiter, and the seed rows must be equipped with a soil coverer.

IV. Field Management

1. Thinning to a Stand

For film-mulched sowing, maintain about 25,000 seedlings per 667 sq m. When the seedlings grow 2 true leaves, thin them, pulling out overly dense and weak seedlings; when they reach 6 leaves or a seedling height of 10 cm, finalize the stand with a seedling spacing of 6 cm. After licorice seedlings emerge, if dead seedlings are found, use 100 g of thiophanate-methyl powder + 250 g of urea + 50 kg of water per 667 sq m, fully dissolve, and spray on the seedling leaves, which can effectively prevent seedling death.

2. Irrigation

Licorice should keep the soil moist before and after emergence to facilitate emergence and seedling growth. For sandy soil with no salinity or slight salinity, irrigate immediately after sowing; for heavy clay soil or soil with heavier salinity, water before sowing and sow while there is still moisture, without irrigating after sowing, to avoid soil compaction and rising salinity and alkalinity. The key to high licorice yield is preserving the seedlings. Generally, irrigate 1-2 times in the sowing year; after the plants have grown, irrigate once in the 2nd year, and once before digging is enough. Too many irrigations will make it difficult for the root system to penetrate downward, and there will be many fibrous roots and hair roots in the 20-30 cm soil-penetrating portion, affecting licorice quality and the marketable rate.

3. Cultivation and Weeding

Cultivation and weeding are carried out after emergence, with the operation quality standard being no furrow pulling, no pile dragging, no burying of seedlings, and no injury to seedlings. In the 2nd spring, before licorice sprouting and when weed seeds begin to sprout, mechanically cut or harrow the land. For plots with many weeds, in combination with harrowing, spray 80-120 g of trifluralin or 2,4-D butyl ester per 667 sq m, which can achieve a very good weeding effect.

4. Fertilization

Apply sufficient base fertilizer before sowing, preferably barnyard manure; phosphate fertilizer 10-15 kg can also be deeply applied before autumn plowing. Licorice roots have rhizobia, so nitrogen fertilizer may be omitted; if soil fertility is low, manually broadcast urea 8-10 kg/667 sq m before the first irrigation.

5. Pest and Disease Control

When licorice has 15 true leaves, if green worms occur, spray with 100-200 g of methamidophos per 667 sq m; if aphids occur, spray with 100 g of omethoate mixed with water. If both pests occur at the same time, the two pesticides can be mixed and sprayed. For rust, powdery mildew, and brown spot in the early stage, use a 1000-fold solution of triadimefon for control; a 0.3-degree Baumé lime-sulfur mixture, or a 500-fold solution of 65% wettable zineb, or a 200-fold solution of dithianon sodium can also be sprayed for control, once every 7-10 days, 2-3 times in succession. Red spiders can be controlled by spraying with a 1:2000 dimethoate emulsion.

6. Autumn Cutting

Cut off the licorice stems in autumn to destroy overwintering sites for pathogens and insect eggs and reduce overwintering eggs; licorice stems are also excellent forage feed.

V. Harvest

1. Licorice quality is best at 3-4 years. Before harvest, first cut off the stems and leaves, then use a chain-type machine or high-horsepower machine with a furrow plow to dig deep along both sides of the rows. Manually pick up the licorice rhizomes.

2. Remove residual stems, fibrous roots, and soil; never wash with water. Cut into different specifications and sun-dry until 60-70% dry, then bundle according to different specifications, tie tightly, pack, and place in a dry, ventilated place until completely dry.

3. Licorice should be stored in a dry, ventilated place. Commercial licorice has a moisture content of 12%-14%, and storage pests of licorice should be controlled. If pests are already present, soak the licorice in lime water for 2-3 hours, or in a clean water pool for half a month; expose the licorice to sunlight. During storage, inspect and disinfect regularly, ventilate frequently, and when necessary, seal with ozone and nitrogen filling for preservation.