What are the technical requirements for standardized cultivation of Atractylodes macrocephala

Standardized cultivation technical requirements for Atractylodes macrocephala

1 Growth and development characteristics

Atractylodes macrocephala must be grown for 2 years before the commercial product can be harvested. In the 1st year, seeds are used to cultivateseedling rhizomes, and in the 2nd year they are planted in the field to harvest thecommercial product. Atractylodes macrocephala seeds begin to germinate above 15 °C, with 25-30 °C being the more suitable temperature for germination; above 35 °C germination is slow and mold rot occurs; above 40 °C all seeds lose viability and become moldy. When the temperature is between 18-20 °C and there is sufficient moisture, seedlings begin to emerge 10-15 d after sowing. Seed germination requires relatively more water; generally, water absorption of 3-4 times the seed weight is needed to promote seed germination. After the seedlings emerge, they can withstand short periods of frost.

In Jingning County, seedling rhizomes are generally sown from late March to early April, emerge 10-15 d after sowing, and are harvested in mid-to-late October, producing 4 500-7 500 kg/hm2 of fresh seedling rhizomes. The seedling rhizomes are stored indoors over winter and transplanted to the field the following year. Field production varies greatly due to climate; in Jingning County, planting is generally from December to January of the following year, and harvest is in early-to-mid November. During the growth period, the aboveground dry weight increases rapidly from March to August, while the underground dry weight increases slowly. From early August to mid-October, nutrients accumulated in the aboveground parts earlier and nutrients produced during this stage are transferred in large amounts to the rhizome, the underground stem expands rapidly, and dry weight increases quickly. From late October to late November, the increase in underground dry weight slows, the aboveground parts begin to decline, dry matter no longer increases, and later it even decreases slightly. The number of days from emergence to harvest is generally 230-240 d. In early-to-mid November, when the stems turn from green to withered yellow, harvesting can begin, generally yielding about 3 000 kg/hm2 of the commercial product.

2 Standardized cultivation techniques

2.1 Suitable growing environment

Atractylodes macrocephala prefers a cool climate and fears high temperature and excessive moisture. When the daily average temperature is below 30 °C, the plant growth rate accelerates as temperature rises; when it exceeds 30 °C, the aboveground growth of the plant is inhibited. Different organs and tissues have different requirements for temperature conditions during growth and development. The suitable temperature ranges required for its growth and development are: 10-15 °C for terminal bud sprouting and growth until emergence, 20-25 °C for aboveground growth, and 24-28 °C for underground rhizome growth. It is advisable to choose sandy loam with good permeability and relatively loose, fertile soil; excessively clayey, waterlogged soil or sandy soil with poor fertilizer retention is not suitable for growing Atractylodes macrocephala. The suitable moisture for Atractylodes macrocephala growth is a soil water content of 30%-50%. Especially in the later rhizome expansion stage, if severe drought occurs and the soil water content is below 10%, rhizome enlargement will be affected. During the growth period, standing water in the field will cause poor plant growth and easily induce diseases. Atractylodes macrocephala growth prefers light, but appropriate shading in the high-temperature season of July-August is beneficial to its growth.

2.2 Site selection and land preparation

Atractylodes macrocephala is cold-tolerant and can endure short periods of low temperature around -10 °C. Seedling land should be selected in areas with a cool climate; for sloping land, generally choose north-facing and northeast-facing mountain slopes and hills, and choose loose, fertile, well-permeable, relatively thick, high and dry sandy loam. Seedling land should not be continuously cropped, to avoid large-scale disease occurrence caused by soil-borne pathogens, generally with an interval of more than 3 years. It cannot be rotated with Chinese cabbage, peanut, Scrophularia ningpoensis, rapeseed, tobacco and other crops harvested for underground rhizomes; the preceding crop is preferably a grass-family crop. Note that when raising seedlings on sloping land, seedling land should be selected progressively upward along the slope year by year to reduce disease occurrence. After the preceding crop is harvested, carry out autumn plowing on the selected land to a depth of 30 cm. During plowing, apply 22.5 t/hm2 of fully decomposed farmyard manure, or 150 kg/hm2 of urea, 375-525 kg/hm2 of phosphate fertilizer, and 112.5-150.0 kg/hm2 of potassium fertilizer as base fertilizer, and turn them evenly into the beds. When preparing the land, plow carefully and harrow finely, breaking the soil into fine, level particles, and make seedbeds 20-30 cm high and 120-130 cm wide, with the beds arc-shaped and the ditches 25 cm deep and 25 cm wide to facilitate drainage.

2.3 Treatment of seedling rhizomes

Soaking seedling rhizomes in chemicals is an important measure for integrated control of diseases such as southern blight and root rot in Atractylodes macrocephala. Before planting, soak the seedling rhizomes in 500-fold dilution of 50% carbendazim or 65% mancozeb for 4-5 h, or soak the seeds in 800-fold dilution of 70% hymexazol wettable powder for 1 h. 2.4 Planting at the suitable time In traditional main production areas, the planting period for Atractylodes macrocephala is very long, generally from mid-November to late February of the following year, with late December to early January of the following year being preferable. Generally, hole planting is adopted, using wide and narrow row planting. On a 1.2 m wide bed surface, plant 4 rows; the row spacing of the narrow rows on both sides is 30 cm, the row spacing of the wide row in the middle is 40 cm, and the plant spacing is about 25 cm. Seedling rhizomes should not be planted too deep; generally the hole depth is about 10 cm, with 1-2 seedling rhizomes placed in each hole. When planting, make the buds of the seedling rhizomes face upward, with the heads aligned but not the tails, and after planting cover with soil level with the bed surface (about 10 cm). When planting, classify by size and plant separately, so that seedlings emerge evenly and quality is improved.

2.5 Fertilizer and water management

From planting to emergence, it takes up to about 3 months. To achieve high yield, sufficient base fertilizer must be applied. Generally apply 105-150 kg/hm2 of urea, 360-450 kg/hm2 of superphosphate, and 105-120 kg/hm2 of potassium sulfate, or apply 525-600 kg/hm2 of compound fertilizer. After planting, if conditions permit, the bed surface can be covered with 15.0-22.5 t/hm2 of fully decomposed farmyard manure; the farmyard manure should be spread evenly, and ditch mud should be taken and spread evenly over the farmyard manure, with a soil covering thickness of 3 cm.

Seedling fertilizer should be applied early and appropriately. Seedling fertilizer is applied in 2 applications. The 1st application after full emergence (called full-emergence fertilizer): apply 112.5 kg/hm2 of urea, 540 kg/hm2 of superphosphate, and 105 kg/hm2 of potassium sulfate, or apply 525-600 kg/hm2 of compound fertilizer, or apply 11.25-15.00 t/hm2 of dilute human manure and urine, in combination with intertillage, weeding and earthing up. The 2nd application is from mid-May to early June during the vigorous growth period of the plants (called vigorous seedling fertilizer): apply 75 kg/hm2 of urea and 52.5 kg/hm2 of potassium sulfate, or 225 kg/hm2 of compound fertilizer. After bud removal, nitrogen fertilizer must be heavily applied as bud-removal fertilizer: apply 150-225 kg/hm2 of urea, or 450 kg/hm2 of compound fertilizer, or apply 15.00-18.75 t/hm2 of dilute human manure and urine.

After heavy application of bud-removal fertilizer, apply a small amount of nitrogen fertilizer and a small amount of phosphate and potassium fertilizer according to seedling condition. Generally from late August to early September, apply 75 kg/hm2 of urea + 15 kg/hm2 of monopotassium phosphate, mixed with 7 500-10 500 kg/hm2 of water and sprayed on the leaf surface. When fertilizing, if the field relative humidity is low and the soil water content is low, try to use watering with diluted fertilizer to increase field humidity and soil water content. If the field relative humidity is high and the soil water content is high, try to switch to hole application or broadcast application when fertilizing.

From February to July, the water requirement is not high, while at this time the production area often has relatively more rain, so drainage work should be the focus. Fields that are easily flooded cannot be used for planting Atractylodes macrocephala. Drainage ditches should be opened around fields planted with Atractylodes macrocephala. According to the size of the field, open 1-3 cross ditches in the middle to facilitate drainage. The drainage ditches should be more than 35 cm deep, so that water dries up after rain stops. After August, the underground rhizome of Atractylodes macrocephala begins to expand and water demand increases. If drought occurs and the field soil water content is less than 10%, appropriate watering should be done to resist drought. Flood irrigation is strictly prohibited (drought resistance may be combined with fertilization).

2.6 Intertillage, weeding and bud removal

After the seedlings emerge, weeds should be removed promptly from May to June. During the seedling stage, intertillage and weeding should be carried out in combination with fertilization. Once plant growth enters the vigorous period (row closure), intertillage and weeding are generally no longer carried out. Except for plants retained for seed production, commercial production of Atractylodes macrocephala requires timely removal of flower buds. From mid-June to early-to-mid July, plants gradually begin to form buds and flower, entering reproductive growth. Therefore, bud removal should be carried out in several rounds, removing them all each time, to reduce nutrient consumption and promote rhizome expansion. Generally, removal is completed in 2-3 rounds over 20-25 d. Bud removal should be carried out on sunny days after the dew has dried. When removing buds, hold the stem with one hand and pick off the flower bud with the other, without damaging the stems and leaves and without shaking the roots of Atractylodes macrocephala.

2.7 Seed retention

In mid-to-late July, select plants with luxuriant growth, thick stems, early flowering at the top of the plant, large flower buds, and no pests or diseases as seed-retention plants, leaving 6-10 flower buds per plant. In early-to-mid November, dig up the seed-retention plants, tie them into small bundles and hang them upside down in a cool, ventilated place. After 15 d, place them in the sun to dry for 2-3 d, take out the seeds, winnow away the fuzz and shriveled seeds, and put them into cloth bags.