Latest Technical Methods Tutorial for Cultivating Polygala tenuifolia
Polygala tenuifolia, also known as xiaocao, xiaojitui, and xiaojicao, has the effects of eliminating phlegm, calming the mind, and improving intelligence and memory. In the national Chinese medicinal herb market, Polygala tenuifolia has commanded high prices for many years. In recent years, the price trend has been relatively stable, with standard goods at 24--30 yuan/kg, yet selected goods on the market are still very few, and large quantities are scarce, with prices also above 35--50 yuan/kg. Because wild varieties are protected, with digging and transport prohibited, and because wild Polygala tenuifolia becomes extinct after a single harvest, the market is currently short of supply. Vigorously developing artificial cultivation provides an unlimited space for development for the vast number of medicinal herb farmers, and the market prospects are promising.
Polygala tenuifolia is a herbaceous medicinal plant that is highly cold-resistant and drought-resistant, with a very wide range of adaptation and no strict requirements for soil. It can grow on barren hills, wasteland, forest belts, grasslands, and plains, but grows poorly in low-lying waterlogged land. Polygala tenuifolia can be planted in three seasons of the year, and planting after thorough rain in arid areas is best; as long as the seedlings emerge, they will no longer die from drought. According to our experiments, dense planting of Polygala tenuifolia can significantly increase yield, with 2--2.5 kg of seed used per 667 sq m, adopting wide-row sowing without thinning seedlings, thus saving a lot of trouble, and only attention to cultivating and weeding is needed. In actual operation, Polygala tenuifolia can be harvested after 2 years of growth, and in the wild, 3 years or perennial growth is also fine. The general yield is 200--250 kg/667 sq m, mixed-grade goods at 25--26 yuan/kg, first-grade goods at 45--55 yuan/kg, with benefits above 5000 yuan/667 sq m. The artificial cultivation techniques for Polygala tenuifolia are introduced below.
Botanical Characteristics of Polygala tenuifolia
Polygala tenuifolia seedlings are about 33 cm tall, with relatively long, cylindrical roots and light brown outer bark. The stems are clustered, with the stem base basically lignified. The leaves are alternate and linear. The raceme is one-sided, with small pale blue flowers. The seeds are black-brown, the flowering period is May--June, and the fruiting period is June--July.
Growth Habits of Polygala tenuifolia
Polygala tenuifolia habitually grows in relatively dry fields, roadsides, hillsides, grass clumps, and other places. It prefers cool climates, avoids high temperatures, and tolerates drought. It is suitable for growing in fertile, moist, well-drained loam rich in humus or sandy loam containing large amounts of humus. Moist or waterlogged land is not suitable for planting, as it causes leaves to turn yellow and fall off.
Cultivation Techniques for Polygala tenuifolia
1. Land Selection and Preparation
According to the growth habits of Polygala tenuifolia, choose high, dry terrain with well-drained loam or sandy loam for planting, and ordinary farmland can also be selected for cultivation. Since Polygala tenuifolia is a perennial plant, sufficient base fertilizer must be applied all at once when plowing. Apply 2500--3000 kg of fully decomposed barnyard manure per 667 sq m, deep plow 25--30 cm, and apply 50 kg of superphosphate when plowing, then rake level and fine, and make flat beds.
2. Planting Techniques
Seed propagation, direct sowing. Generally, water the prepared plot thoroughly, and sow after the water has completely seeped down. The sowing rate is 2 kg per 667 sq m. Before sowing, soak the seeds in water for 12 hours, remove them, and mix with 3--5 times fine sand. Open shallow furrows on the bed surface at a row spacing of 18--21 cm, evenly scatter the seeds into the furrows, and cover with soil. After sowing, press lightly and water. About 15 days after spring sowing, seedlings emerge; after winter sowing, seedlings emerge in the spring of the following year.
3. Field Management
(1) Thinning and replanting. When seedlings are 3--5 cm tall, thin them at a plant spacing of 3--6 cm, and replant missing spots in time.
(2) Loosening soil and weeding. Polygala tenuifolia plants are short, and seedlings grow slowly, so attention should be paid to loosening soil and weeding, pulling weeds as soon as they appear. Loosen the soil shallowly, use a rake to lightly and evenly loosen the ground surface, doing this 2 times in a row, keeping the soil surface loose and moist, and avoiding weeds covering the plants.
(3) Watering and fertilizing. Polygala tenuifolia prefers dryness; except for appropriate watering during seed germination and the seedling stage, it generally does not need frequent watering in the later growth stage. Apply topdressing once each in winter and spring every year and once during April--May, mainly phosphorus fertilizer, with 20--25 kg of cake fertilizer or 20 kg of superphosphate applied per 667 sq m.
(4) Foliar topdressing. From mid-June to mid-July each year, spray 50--60 kg of 1% potassium sulfate or 80--100 kg of 0.3% potassium dihydrogen phosphate per 667 sq m, spraying once every 10 days for 2--3 consecutive times, with spraying after 5 p.m. being best. Spraying potassium fertilizer can enhance the disease resistance of Polygala tenuifolia, promote root growth and expansion, and further increase root yield.
4. Pest and Disease Control
(1) Root rot. It occurs in rainy seasons and damages the roots. Field management should be strengthened; diseased plants found should be pulled out and burned in time, and in the early stage of the disease, spray 1000-fold 50% carbendazim solution 2--3 times every 6--7 days.
(2) Leaf blight. It is prone to occur in high-temperature seasons and damages the leaves. The control method is spraying 800--1000-fold mancozeb solution or 800-fold metalaxyl solution on the leaves 1--2 times.
(3) Aphids. Spray with 1500-fold 40% omethoate solution, once every 6--7 days, for 2 consecutive times.
Harvesting and Processing of Polygala tenuifolia
1. Harvesting: Seeds should be harvested promptly when the fruit matures in July--August. The roots can be harvested in the second year, digging up the roots in autumn after the aboveground parts wither.
2. Processing: After digging out the roots, remove soil and impurities, and while the moisture has not dried, select thick, large, and neat ones and place them on a flat board, rubbing back and forth until the bark and flesh separate from the woody core, pull out the woody core, and dry in the sun to obtain Polygala tenuifolia tubes. For smaller roots, beat them with a wooden stick to make them soft, remove the woody core, and dry in the sun; because the bark does not form a tube shape, it is named “Polygala tenuifolia flesh”. Those too small to have the woody core removed are called “Polygala tenuifolia roots”. Sun-dried Polygala tenuifolia is stored in a dry, ventilated place. Polygala tenuifolia with thick tubes, thick flesh, and completely removed woody core is considered best.