Detailed Cultivation Techniques for the Chinese Medicinal Herb Sichuan Corktree (Phellodendron chinense)

Site Selection and Land Preparation

The seedling nursery should be chosen on a wind-sheltered, sunny site with deep soil, good drainage, and fertile sandy loam. The land should be leveled and harrowed fine, with 2500-3000 kg of fertilizer and 25-30 kg of superphosphate applied per mu. Then form large ridges 60 cm wide or raised beds 1.2 m wide, ready for sowing. For afforestation, choose suitable plots with a slight slope that favors drainage. The corktree has strong climatic adaptability; seedlings can tolerate slight shade, while mature trees prefer sunlight. It is best to select a wind-sheltered mountain valley with deep, fertile, moist, slightly acidic or neutral loam for cultivation. First carry out full clearing or strip clearing, then dig planting holes. Land clearing can be done during the slack farming season.

Planting Methods

1. Seedling Raising

Seed collection: Select fast-growing, high-yielding, high-quality mature trees over 15 years old for seed production. In the north, collect from September to October; in the south, from October to November, when the fruits ripen and turn black. After collection, place the fresh fruits in a vat to soak or pile them up (in a corner of the house or in a wooden barrel), cover with rice straw, and after 10-15 days, once the fruit pulp has rotted, mash and rub them in water to wash out the seeds. Dry them in the shade or in the sun, and store in a cool place (at a temperature of 3-5°C). The seeds can retain their germination capacity for more than two years.

Seed treatment: Generally, seeds collected in the current year are used for autumn sowing and require no pre-germination treatment. For spring sowing, however, seed treatment is necessary. In October, mix the seeds with 3 times their volume of wet sand, bury them in a pit 30 cm deep, cover with 10 cm of soil, then cover with weeds. Take them out before sowing the following spring, remove the sand and soil completely, and they are ready for sowing.

Sowing methods: In the north, ridge planting is mostly used. Autumn sowing should be done in November, before the ground freezes; spring sowing from late April to early May. Rake the ridge surface level, open two rows of furrows per ridge, with a row spacing of 15-20 cm and a furrow depth of 5-6 cm. Firm the furrow bottom, scatter the seeds evenly in the furrows, cover with 1-2.5 cm of soil, and press down. For bed sowing, open furrows lengthwise along the bed surface; the method is basically the same as ridge planting. The sowing rate is about 4-5 kg per mu. In the south, spring sowing is mostly used, carried out in early to mid-March. Soak the seeds for 24 hours, air-dry briefly, and sow immediately. Open furrows crosswise on the raised bed, with a furrow spacing of 30 cm, a furrow depth of 3 cm, and a sowing width of 10 cm. Apply manure water as a base fertilizer in the furrows at 1000-1200 kg per mu, then scatter the seeds evenly into the furrows, cover with 1 cm of soil, and cover the bed surface with rice straw. The sowing rate is 2-3 kg per mu. The seedbed should be kept constantly moist, and watered promptly in dry weather. Generally, seedlings emerge successively over 40-50 days, at which point the mulch is removed. When the seedlings are 7-10 cm tall, thin them; when 17-20 cm tall, finalize the spacing at 7-10 cm.

2. Transplanting

Transplanting for seedling cultivation: The seedlings can leave the nursery in the same year. Transplant in early winter or the following spring for seedling cultivation. Cut off a portion of the overly long roots of the seedlings, use a row spacing of 60 cm and a hole spacing of 50 cm, firm the soil after planting, irrigate, and close the holes after the water has settled. Seedling cultivation takes 2-3 years; under close planting conditions, the main trunk of the seedling grows straight, tall, and branchless.

Transplanting for afforestation: Generally, use a row spacing of 1.5 m and a plant spacing of 2 m, with holes 60-70 cm wide and 40-50 cm deep. After planting, fill with soil, irrigate, and close the holes.

3. Field Management

During the seedling stage and the seedling cultivation stage, loosen the soil and remove weeds promptly to ensure the field is free of weeds. In conjunction with soil loosening, apply a topdressing once a year, with 1500-2000 kg of human and livestock manure water, 10-15 kg of ammonium sulfate, or 2500 kg of barnyard manure per mu. When it is too dry, water or irrigate to ensure survival and vigorous growth. During the forest establishment stage, carry out one intertillage per year to promote growth. After the forest is established, thinning can be carried out in stages according to the density of the stand, until a final stand of suitable density is achieved.