Detailed Guide to Licorice Cultivation: Planting Methods and Management Essentials

Licorice, also known as sweet grass or sweet root, has the effects of harmonizing medicinal properties, reducing or alleviating drug toxicity, and moistening the lungs. It also has the characteristics of cold resistance, heat tolerance, drought tolerance, sensitivity to waterlogging, and light preference, making it an excellent plant for windbreaks and sand fixation. Its cultivation techniques are as follows:

For site selection and land preparation, sandy soil with deep soil layers, a deep groundwater table, and good drainage should be chosen. The soil salt content should preferably not exceed 0.2%. Areas with excessive rain or where the soil is relatively clayey and drainage is poor are not suitable for planting, because the roots tend to rot or the main root is short, with many lateral and fibrous roots, resulting in low economic value. The seedling nursery should preferably be chosen on relatively flat land with a water source. For transplanting sites, cultivated land, barren slopes, and barren beaches can all be used. Before land preparation, apply base fertilizer first, mainly organic fertilizer, applying 15,000-45,000 kg of decomposed barnyard manure and 300-450 kg of diammonium phosphate or superphosphate per hectare, then plow deeply to about 25 cm, and then harrow finely and level according to the terrain. The seedling nursery should preferably be made into flat beds to facilitate irrigation.

Propagation and transplanting: Licorice is propagated by seed, but the seed coat is hard and impermeable, making germination very difficult, so the seeds must be treated before sowing. Treatment by hulling and rubbing with a rice mill gives the best effect; generally, one pass through the mill can achieve a germination rate of 95%. The method for checking whether the treatment is qualified is to soak the hulled seeds in a small amount of water for 2-4 hours. If most of the seeds have swollen, the treatment is qualified; if not, a second pass through the mill can be done; if the seed coat has broken, it means the hulling was excessive and the seeds will not be able to germinate. In addition, harvesting tender, plump seeds can achieve a germination rate of 95%; they should be harvested when the pods are green with a slight purplish-red tinge, dried and threshed, then winnowed to remove impurities and shriveled seeds, leaving light brown plump seeds that can be sown directly. Sowing can be done from late April to mid-August, but May is best; in places without irrigation conditions, sowing should be done in the rainy season. When sowing, open furrows at a row spacing of 20-25 cm for drilling, with a seeding rate of 30-38 kg per hectare. In places with irrigation conditions, sow shallowly at about 1 cm; in arid areas without irrigation conditions, sow deeply at about 2-3 cm. Water promptly after sowing and keep the surface soil moist before emergence; after emergence, gradually reduce the frequency of watering as the seedlings grow. During the seedling stage, cultivate and weed frequently. When the seedlings reach 10-15 cm, apply a nitrogen fertilizer once, such as urea or ammonium nitrate, at 120-150 kg per hectare. Generally, transplanting can be done in the spring of the second year; for autumn-sown seeds, transplant in the spring of the third year. The transplanting period is generally from after the surface soil thaws in early spring to before emergence. When transplanting, first dig up the root seedlings, cut off the seed root, leave the root tip 40-50 cm long, separate them by thickness, and plant them separately. When transplanting, dig furrows 10-15 cm deep at a row spacing of 40-50 cm, and place them staggered in the furrows at a plant spacing of 15-20 cm.

Field management: After planting, pay attention to cultivation and weeding, and water promptly. During the growing period, pay attention to topdressing; according to the plant growth condition, apply topdressing 1-2 times each year, the first time after emergence in April-May, the second time during the vigorous growth period in June-July, each time applying 20-30 kg of diammonium phosphate, applied deeply in furrows opened beside the roots, then cover with soil and water after application.

Pest and disease control: For rust disease, in the early stage of onset, spray with 25% triadimefon wettable powder at 1000 times dilution for control, spraying once every 7-10 days, for a total of 2-3 sprays. For powdery mildew, spray with 50% thiophanate-methyl wettable powder at 1000 times dilution for control, spraying 1-3 times depending on the severity of the disease. For the licorice seed wasp, spray with 40% dimethoate emulsifiable concentrate at 1000 times dilution for control. For aphids, spray with 40% dimethoate emulsifiable concentrate at 1000-2000 times dilution for control, spraying once every 10-15 days, for 2-3 consecutive sprays.