Methods for Cultivating Strong Seedlings in Coptis chinensis Planting
Coptis chinensis is one of China's precious medicinal herbs. It is a perennial herbaceous crop that grows in high mountains at an altitude of 800-2000 m. The seedling growth period of Coptis chinensis is 1-2 years, and the growth period after transplanting is 4-5 years. After long-term production practice, medicinal herb growers in Emeishan City, Sichuan, have summarized a set of new experiences for cultivating strong Coptis chinensis seedlings. They cultivate 50 million strong Coptis chinensis seedlings each year. In addition to meeting local large-scale planting needs, they also sell large quantities to Yunnan, Ebian, Jinkouhe, Hongya, Xindu and other places, promoting production development in various regions. Medicinal herb growers obtain an economic benefit of 3000-5000 yuan per mu from seedling cultivation. The techniques used by local medicinal herb growers to cultivate strong Coptis chinensis seedlings are introduced below:
1. Seed collection The Coptis chinensis seed maturation period is around the “Start of Summer” in May. Seeds produced three or four years after Coptis chinensis seedlings are transplanted have good quality and a high germination rate. When the seed shell turns yellow and the seeds become yellow-brown, and when pressed with a fingernail the flesh is segmented with no water bubbles, they are mature. When harvesting, choose a sunny day with no dew, gently cut the seed stalk with scissors, put the seeds into a cloth bag and transport them home. Place them indoors on a ventilated, dry winnowing basket or bamboo mat for 1-2 days, then gently rub out the seeds by hand and remove fruit skin, branches, leaves and other debris. Spread the threshed seeds on a winnowing basket or bamboo mat covered with plastic film to cool, at a thickness of about 1 cm, turning 1-2 times daily, and leave for 6-10 days. Store when all the seeds have turned yellow-brown and do not stick to the hand when touched.
2. Seed storage After harvest, Coptis chinensis seeds enter dormancy. Under natural conditions, the dormancy period lasts as long as 6 months. Only after the dormancy period can sowing germinate. Only after safe storage can they be sown for seedling cultivation. The physiological characteristics of Coptis chinensis seeds are that they prefer shade, moisture and low temperature, and fear drying out, sunlight and waterlogging. If too dry, they cannot germinate. Storage methods:
1. Sand-mud mixing storage method: Take sand and mud from Coptis chinensis fields, sieve out small stones, grass roots and debris. The suitable dryness and moisture level is when it forms a ball when squeezed by hand and crumbles when released. The weight ratio of seeds to sand-mud is 1:3. After mixing the seeds and sand-mud evenly, store them in a wooden box or large-mouthed ceramic jar, with a layer of plastic film at the bottom, a 5 cm thick layer of sand on top, and then a layer of palm leaves. A seed storage chamber with a width and height of 50 cm each and a length as needed can also be built against an indoor wall base. Open windows for ventilation at any time during high-temperature seasons. When the storage sand is too dry, spray appropriate water to maintain moisture. Be careful not to let chickens, dogs, cats or rats defecate or urinate on the storage sand, which would cause the seeds to rot.
2. Clean seed bag storage method: Put the seeds in a hemp bag or cloth bag, filling one third of the bag, and seal the bag opening tightly. Then choose an outdoor plot with a slope of about 15 degrees and dig a rectangular pit 15 cm deep and 1 m wide, with length as needed. Place a 2-3 cm thick layer of river sand at the bottom of the pit, then place the seed bags in the pit in sequence. Flatten the seed bags so that the seed thickness inside the bags is 3-5 cm. Cover the bag surface with about 5-8 cm of fine soil. Dig drainage ditches 20 cm deep around the seed storage pit. Finally, build a shade shed with bamboo, wood or plastic film to maintain moisture and avoid sunlight. The shed height is about 1 m, and the surroundings should be tightly enclosed with fencing.
3. Site selection and land preparation For the seedling site, gentle-slope virgin wasteland is best, because virgin wasteland has relatively fertile soil, no pathogen contamination and few weeds. Cultivated land tends to grow weeds and is not suitable as a seedling site. September-October is the best time for land preparation and seedling cultivation. Land preparation method: Cut weeds and trees and burn them to ash for later use, dig out tree stumps and grass roots, pick up stones and residual branches and fallen leaves, shallowly turn the topsoil 10 cm deep with a rake or hoe, rake the soil fine and level it, make beds 1.3 m wide with length as needed, open boxes and make beds along the slope, and dig drainage ditches well.
4. Build a shade shed On the center line of the back of the box, drive a wooden stake every 2 m. The stakes are 1.6 m high, and the upper ends are made into a “y”-shaped bend to place and tie bamboo and wood branches to build a shade shed, or using black plastic shade netting to build the shed gives a better effect.
5. Sow at the right time: October-November is the best sowing time. Use 2-3 kg of clean seed per mu of seedbed, which can cultivate 250,000-400,000 strong seedlings. Sowing method: Mix the seeds with fine soil at 1:3 and stir evenly, then sow them in sequence on the box beds. To achieve uniform density, sow repeatedly in 2-3 batches. Then dig fine soil from the box ditches, mix it with an appropriate amount of plant ash, and spread it over the box surface at a thickness of about 1 cm, sufficient to cover the seeds. Then set up the shade shed.
6. Seedbed management: To cultivate high-quality strong seedlings, the following management measures must be carried out well:
1. Remove debris: After the seeds emerge, remove dead branches, fallen leaves and other debris from the seedbed at any time so that the seedlings grow smoothly.
2. Remove weeds: Some weeds grow together with Coptis chinensis seedlings, competing with each other for fertilizer and light, and must be removed in time. Generally, weed once each in March, June and August. When weeding, protect the weak and small Coptis chinensis seedlings. Do not damage the Coptis chinensis seedlings when pulling weeds. Press back any loosened Coptis chinensis seedlings by hand immediately, and spray a seedling-protecting water at once to prevent the leaves from losing water, turning yellow and stopping growth.
3. Fertilize to promote seedlings: When Coptis chinensis leaves grow 3-5 leaves, begin applying topdressing. Generally apply once each in April, July and September. Method: For the first application, use 50-80 kg per mu of plant ash mixed with an appropriate amount of oil cake and dried chicken manure fertilizer, mix with an appropriate amount of fine soil, and broadcast on a sunny day. For the second application, apply 15-20 loads per mu of decomposed, residue-removed human and livestock manure water, adding 100 g of urea to each load and sprinkling it. For the third application, broadcast 3-5 kg of urea per mu, or spray 2-3 kg of monopotassium phosphate on the leaves on a cloudy day with no dew. After application, immediately sweep the urea off the leaf surfaces of the Coptis chinensis seedlings with bamboo branches to prevent burning the leaves.
4. Thin seedlings at the right time: Thinning seedlings is an important measure for cultivating strong seedlings. Some seedlings are too dense and crowded, competing with each other for fertilizer and light, causing the seedlings to turn yellow and die. Thinning methods: First, while pulling out weeds, pull out and evenly separate the overly dense weak seedlings with 3-5 leaves and transplant them into thinner empty gaps, so that the seedling spacing reaches 1 plant per 1 square cm. Second, remove strong ones and keep weak ones, and remove seedlings in batches. For 1-1.5-year-old seedlings, transplant strong seedlings with 6-14 leaves first, and keep weak and small seedlings in the ground for continued cultivation. After each batch of seedlings is removed, apply water and fertilizer once in time until all are removed.
7. Disease and pest control Common diseases and pests during the Coptis chinensis seedling stage mainly include dry wilt disease, powdery mildew and anthracnose, old wood worms, armyworms and mountain rat damage, etc. Control methods:
1. Dry wilt disease Main symptoms: When the seedbed soil is thin, poor and dry, or when the shade shed is damaged and exposed to scorching sun, Coptis chinensis seedlings become stiff and old or lose water and dry up. Control methods: The seedbed should be selected as a plot with high humus content, thicker soil layer and good water retention for seedling cultivation. Dig a small water pool near each mu of seedbed that can hold 2 cubic meters of water, and fill it with water for later use. Check the seedbed shade shed at any time. If it collapses or is damaged by wind, repair it immediately.
2. Powdery mildew Main symptoms: Blocky gray-white spots appear on the leaf surfaces of diseased plants, with powdery substances, and the leaves wither and dry up. Control methods: Sulfur suspension concentrate can be used, with each bottle diluted in 40-50 kg of water, or 50% thiophanate-methyl wettable powder at 1000 times solution, or 65% zineb wettable powder at 500 times solution, sprayed alternately 2-3 times, once every 10 days.
3. Anthracnose Main symptoms: Oil-soaked disease spots appear on the leaves of diseased plants. The spot edges are dark red and the centers are gray-white. In the later stage, the centers of the disease spots easily perforate. Brown disease spots appear on the petioles, and in severe cases the whole plant dies. Control methods: Alternating use of zineb and thiophanate-methyl wettable powder 3-4 times can cure it. The method is the same as for powdery mildew.
4. Mountain rat damage Damage situation: When field rats and bamboo shoot rats dig holes underground in the seedbed to seek food, they dig crisscrossing tunnels. The soil dug out presses down the seedlings and causes them to rot and die. The soil layer on the rat tunnels becomes dry and loose, causing Coptis chinensis seedlings to turn yellow and stop growing. Control methods: Use rodenticide to make poison bait and place it at the tunnel openings to lure and kill them, or set various mousetraps to catch and kill them.
5. Old wood worm, also called “white soil grub” Damage situation: Old wood worms hide in the humus soil of rotting tree stumps. The larvae bite and eat tender leaves, causing seedlings to die. Control methods: Use 90% trichlorfon at 1000 times solution and spray 1-2 times to kill them.
6. Armyworm Damage situation: The larvae mainly damage tender Coptis chinensis leaves. It is a voracious pest, and once it occurs, the damage is very great. Control methods: Use 50% dichlorvos emulsifiable concentrate at 800 times solution for spray control, or use 25% dimehypo aqueous solution at 600 times solution for spray control.