Detailed Explanation of Key Production and Cultivation Techniques for Schisandra chinensis
Schisandra chinensis, also known as wuweizi, is a perennial deciduous woody vine. In recent years, its market prospects at home and abroad have been promising, offering good economic and social benefits. The cultivation techniques are summarized below for reference and guidance.
I. Growing environment and morphological characteristics. During the seedling stage, Schisandra chinensis requires moderate shade and prefers well-ventilated and well-lit environments with deep humus soil or loose, fertile loam.
Schisandra chinensis is a perennial deciduous woody vine that twines to the left, reaching a height (length) of 10-15 m, generally 4-8 m. Schisandra chinensis prefers relatively moist soil without standing water; it likes moisture but is not tolerant of flooding, and likes light but not intense light. The old vine bark is dark brown, while young vines are dark red or pale yellow, with prominent lenticels; leaves are simple and alternate, the petiole is red when young, the leaf blade is broadly obovate to broadly elliptical, with sparse teeth along the margin; buds are mixed buds; flowers are unisexual and monoecious, with ligulate petals, axillary, borne on long pendulous pedicels; the fruit is an aggregate berry, fleshy, clustered into a long spike shape somewhat resembling a sphere, red when mature, with a wrinkled surface after drying; seeds are kidney-shaped, yellow, with a smooth surface, and the kernel is oily; the primary root is not obvious, and it has rhizomes that run horizontally underground, with nodes bearing scale-like leaves and buds, distributed 5-15 cm below ground; once exposed above ground, they develop into shoots.
II. Biological characteristics
1. Light preference: Except for one-year-old seedlings that are afraid of scorching sun exposure, all stages prefer ample sunlight. Insufficient light leads to slow growth and reduced fruiting rate.
2. Shade tolerance: It can grow for a long time under weak light without dying. Therefore, during the growing period, a shade level of about 20% is suitable.
3. Cold tolerance: Schisandra chinensis can overwinter safely at minus 35°C; at minus 40°C, only the tips of seedlings and new shoots suffer slight frost damage, basically not affecting the next year's growth. When the leaves first unfold in spring, they may encounter general frost damage, but the stems will not be frozen to death at around 0°C. After thawing, growth can continue, but the new leaves will fall off, and subsequent new leaves will grow. If early frost damage occurs in autumn, the stems are not harmed, and the leaves fall off one after another.
4. Moisture preference and drought sensitivity: During the seedling stage, the leaves are large, transpiration is high, and it is not cold-tolerant. Schisandra chinensis likes moisture but also fears waterlogging; low-lying areas with standing water or soil that is excessively wet for a long time are not conducive to growth.
5. Regeneration: During the growing or dormant period, if the aboveground plant of Schisandra chinensis dies mechanically, the underground roots still survive. From May to July each year, many basal roots emerge from the root crown and underground stems of Schisandra chinensis. However, seedlings of Schisandra chinensis do not have this characteristic.
6. Growth and development are dynamic: The root system of Schisandra chinensis begins to sprout when the temperature reaches about 6°C, gradually becoming more vigorous with flowering and young fruit enlargement, and then growing slowly after the berry ripening stage. Shoot growth of Schisandra chinensis begins after bud break; new shoots initially grow slowly, then grow rapidly when the temperature reaches about 20°C in June; they reach a growth peak in early July and finish growing by the end of August. Berry growth begins after flowering ends; the ovary rapidly enlarges, and when the temperature reaches 25°C, the locules and flesh inside the fruit grow vigorously, and young fruit growth reaches its peak.
III. Seedling propagation techniques
(I) Sexual propagation
(1) Seed collection: When seeds mature from August to late September, collect them manually. After harvesting (or after soaking in water for several days before seed treatment), rub off the flesh and float away the shriveled seeds.
(2) Seed treatment: In late December, soak the seeds to be treated in water for about one week so they absorb enough water, changing the water every 2 days. Remove and drain them, then mix with disinfected river sand at a seed-to-sand ratio of 1:3, with humidity above 60%. Then place them in a wooden box or flowerpot and put them in an outdoor pit or cellar about 50 cm deep, cover with 10-15 cm of fine soil, and then cover with straw curtains for low-temperature treatment. By May of the following year, the seeds will split and can be sown.
(3) Site selection, land preparation, bed making, and base fertilizer application: Choose sandy soil with good drainage, loose texture, and strong water and fertilizer retention. Perform autumn plowing or spring plowing and harrow well to achieve fine land preparation. Apply sufficient base fertilizer, with 2500 kg of decomposed pig manure per mu. Before sowing, make the seedling bed, with a bed width of 1-1.2 m, a bed height of 15 cm, and a bed length depending on the terrain.
(4) Sowing: For seeds that have undergone germination treatment, sow in spring from late April to early May. Use horizontal drilling: sow the seeds evenly into furrows at a row spacing of 10-15 cm and a furrow depth of 3-4 cm, then cover with 2-3 cm of fine soil after sowing. The sowing rate is 25-30 g per sq m. Press lightly, level the bed surface, water thoroughly, and cover the bed surface with a thin layer of grass to keep the soil moist and facilitate seedling emergence.
(5) Seedling management: After sowing, water frequently to keep the bed soil moist. Seedlings can emerge successively after 30-40 days, with the peak emergence in mid-June, basically ending in early July; the emergence process lasts about 30 days. After the seedlings emerge, remove the covering. When 60% of the seedlings have emerged, promptly build a shade frame, with a height of 60-70 cm, covered with straw curtains or reed curtains for shading. When the seedlings grow 4-5 true leaves, the shade curtains can be removed, and weeding, loosening the soil, and thinning can be carried out at the same time. The spacing of the retained seedlings should reach 7-10 cm to cultivate large and strong seedlings. Seedbeds that have already received base fertilizer do not need additional topdressing that year. Those without base fertilizer should receive the first topdressing at this time, applying 20-25 g of ammonium nitrate per sq m; the second topdressing should be applied when the seedlings are about 10 cm tall, applying 30-40 g of diammonium phosphate per sq m. Fertilizer should be applied in furrows between rows, with a furrow depth of 3-5 cm. After fertilizing, watering frequency should be appropriately increased to promote seedling growth.
(II) Asexual propagation
In early April, after sap flow begins in the branches of Schisandra chinensis, select one-year-old branches and cut them into 15 cm long cuttings. Soak them in 150 ppm ABT No. 1 rooting powder for 6 hours, then insert them into a cutting bed at a plant spacing of 3-5 cm and a depth of 5 cm. The cutting bed should be prepared in advance by mixing 3 parts humus soil and 1 part sand. Insert the cuttings at a 45° angle to the bed surface; the cuttings should be neat and uniform, aligned in rows horizontally and vertically, and watered thoroughly.
IV. Nursery stock lifting and planting
1. Nursery stock lifting: For sexually propagated nursery stock, select 2-year-old plants with robust growth and intact primary and lateral roots. After planting, they are suitable for slow seedling recovery and grow vigorously; for asexually propagated cuttings, seedlings can be lifted when the stem has lignified to 10-20 cm. Water thoroughly before lifting the seedlings, and dig when the water has drained and the soil is dry, so as to ensure seedling quality. Seedlings not to be transported or those that cannot all be planted should be heeled in for storage. Choose a wind-sheltered, sunny plot or open a heel-in trench in the original nursery with a width of 100-150 cm, a depth of 30-50 cm, and a suitable length, oriented due south-north. Place the seedlings in rows with roots facing downward and slanting toward the sun at 40° to the ground. After placing each row, cover and press down the roots with wet sand, leaving the upper 1/3 above ground, and cover with wet grass or straw curtains.
2. Planting of nursery stock: Planting can be done from late April to late June. Open holes on the previously backfilled planting trench for planting, with a plant spacing of 1 m. A rope can be used to position the holes to keep them neat. After positioning the holes, dig planting holes 30-35 cm deep and 30 cm in diameter, and plant one plant per hole. After covering with soil and firming, irrigate thoroughly, and after the water infiltrates, seal the hole with soil. Check for missing plants and replant after 15 days.
V. Field management
1. Irrigation and fertilization: Schisandra chinensis likes fertilizer and water, and requires a sufficient supply of water and nutrients during the growing period. After establishment, water frequently to keep the soil moist, and irrigate once before freezing to facilitate overwintering. Apply topdressing twice each year: the first before leaf unfolding in mid-to-late May, and the second during flower bud differentiation in early-to-mid July. Apply 35 kg of compound fertilizer, 10 kg of potassium sulfate, and 15 kg of diammonium phosphate per mu. The fertilization method is to open a ring-shaped furrow 15-20 cm deep at a distance of 30 cm from the roots, apply the fertilizer, and then cover with soil. At the same time, carry out autumn fertilization each year, applying 2500 kg of high-quality barnyard manure per mu. Open furrows 15-20 cm deep on both sides of the plants at a distance of 30 cm from the plants, apply the fertilizer, and then cover with soil.
2. Trellising: Set up the trellis in the second year after planting, or it can be set up in the same year. Use hard miscellaneous wood poles 2.6 m long and 8-12 cm in diameter (concrete posts are best). Between rows and plants, bury one post every 10 m and 20 cm away from the planting plant. At a burial depth of 50 cm, pull the first horizontal wire, then pull one more every 50 cm upward. The wire should be pulled straight and tight and tied to the posts with iron wire (for concrete posts, nails can be fixed in advance during pouring). Then place a bamboo pole 220-240 cm long and 1.5 cm in diameter at the base of each Schisandra chinensis plant, and fix the bamboo pole to the horizontal wire with rope.
3. Leading vines onto the trellis: According to the main vines selected and retained for each plant, lead 1-2 main vines per trellis strip in a left-twining direction.
4. Pruning: It takes 3-4 years from planting to the initial fruiting stage for Schisandra chinensis; during this time, the main task is to select and retain main vines to form the plant framework. Schisandra chinensis can be pruned in spring, summer, and autumn. Spring pruning is carried out before the branches begin to sprout, cutting off overly dense branches and dead branches so that the branches are appropriately spaced and do not interfere with each other; summer pruning is carried out in early May, mainly cutting off basal branches, overlapping branches, and diseased and pest-infested branches, and also thinning and heading back overly dense new shoots. If summer pruning is done properly, light pruning or no pruning can be done in autumn; autumn pruning is carried out after leaf fall, mainly cutting off basal branches. Regardless of the type of pruning, 2-3 basal branches should be selected and retained and led onto the trellis.
5. Tending: Generally, intertillage and weeding are not advocated. Because the underground stolons of Schisandra chinensis are distributed very shallowly, turning the soil layer is likely to damage the underground horizontal stolons and cause a large number of basal branches to emerge from the ground. Instead, ditch clearing and soil covering should be adopted. This is done 4 times a year: the first in late May when a large number of small weeds appear; the second and third in June-July, first pulling out large weeds and then clearing ditches and covering soil; the fourth in August, when only large weeds need to be pulled out. Through ditch clearing and soil covering, weed growth is suppressed and the soil layer is thickened, which is beneficial to the growth of underground horizontal stolons.
VI. Pest and disease control. (1) Powdery mildew: Often appears in late July. In mid-July, use Bordeaux mixture (1:1:100) for prevention, once every half month, for 3-4 consecutive times. Once it occurs, spraying with 800 times fenarimol is sufficient. (2) Leaf blight: Spray with 800 times Tuzet, carbendazim, or shuangxiaoling. (3) Root rot: Often occurs from early May to late July. When it occurs, drench the roots with 50% carbendazim 800 times solution. In the early stage, take care to keep the soil from accumulating water. (4) Foam cicada: Often occurs and causes damage from May to August. Before the larvae roll the leaves, spray with trichlorfon for control; after the leaves roll, spray with omethoate for control.