Key Techniques for High-Quality and High-Yield Cultivation and Management of Pinellia ternata
I. Site Selection and Preparation. Pinellia ternata prefers a warm and humid environment. The planting site should be chosen as a small flat area on gentle mountain slopes at high altitude, with loose, fertile, moist soil and not strong sunlight. The land should be plowed and broken up several times. Apply 3000-4000 kg of farmyard manure per mu as base fertilizer. Make raised beds 20 cm high and 100-120 cm wide. Since Pinellia ternata is a shade-tolerant plant, it can be intercropped under orchards and tall crops.
II. Propagation Methods
(1) Corm propagation. In November-December, select disease-free, uninjured corms with a diameter of 1.2-1.3 cm for seed use. Place them in a ventilated area to air-dry for 1-2 days, then store them in a cool indoor location, or plant them in the same year they are harvested.
(2) Bulbil propagation. In summer and autumn, when the old leaves are about to wither, collect the bulbils growing on the leaf stalks and plant them. The planting time for Pinellia ternata is generally from late March to early April each year. Before planting, grade the corms by size and plant them separately for easier management. Open furrows at a row spacing of 15-20 cm (furrow depth about 5 cm), then evenly sow the corms or bulbils in the furrows at a plant spacing of 1.5 cm. Cover with soil level with the bed surface, then cover with a layer of rice straw or seedless weeds, and water the bed surface thoroughly. Generally, sow 100-120 kg of corms or 50-60 kg of bulbils per mu.
III. Field Management
(1) Timely topdressing. Pinellia ternata is a fertilizer-loving plant. Apply the first topdressing after seedling emergence, using 1000-2000 kg of decomposed human manure per mu. Thereafter, apply additional topdressings several times depending on seedling condition. After Xiaoman (Grain Full), when the first batch of bulbils has produced many new plants, the plant density in the field increases, and the corms grow rapidly, requiring more water and fertilizer. In addition, heavy applications of manure, cake fertilizer and urea are needed. Apply 4000-5000 kg of a mixed fertilizer of decomposed barnyard manure and grass turf ash per mu, plus 50 kg of peanut bran (crushed and composted), broadcast on the bed surface. After fertilizing, immediately earth up to prevent fertilizer loss.
(2) Good drainage, irrigation and earthing up. High temperatures and dry soil often cause the plants to turn yellow and wither, or even die back, directly affecting tuber growth. Therefore, throughout the entire growth and development period of Pinellia ternata, the soil should be kept moist at all times to promote plant and tuber growth. During the rainy season, drainage should be carried out well to prevent corm rot. After June each year, mature seeds and bulbils successively fall to the ground. It is advisable to earth up twice from Mangzhong (early June) to Xiaoshu (early July) to facilitate bulbils entering the soil and growing into new robust plants. For earthing up, take soil from the bed edges, break it up, and evenly spread it on the bed surface to a thickness of about 1.5 cm, then smooth the soil by hand to prevent water accumulation.
(3) Timely bud removal. To promote corm growth and reduce nutrient consumption, when the plants bolt, remove the flower buds that emerge in stages and batches. In addition, Pinellia ternata has strong reproductive capacity. After bulbils fall to the ground, they grow extremely fast and are difficult to clear. Therefore, when the spathe emerges, it must be removed so that the corms accumulate more nutrients, thereby increasing the yield of Pinellia ternata.
IV. Pest and Disease Control
(1) Corm rot. It generally occurs during the rainy season and in low-lying waterlogged areas. After onset, the corms rot and the aboveground stems and leaves wither. Control methods: Pay attention to drainage. In the early stage of the disease, pull out diseased plants and pour 5% lime water into the diseased plant holes, or scatter lime powder at the diseased holes to prevent the disease from spreading.
(2) Leaf curl disease. A disease caused by a virus, mostly occurring in summer. After onset, the leaflets shrink and twist, and the plants become shorter and deformed. Control methods: First, thoroughly eliminate the aphids that transmit the disease source; second, select disease-free plants for seed preservation.
(3) Aphids. Their adults and larvae suck the sap of tender leaves and buds, causing leaves to turn yellow and plant growth to be hindered. Control methods: First, during the aphid occurrence period, spray with a 1500-2000 times diluted solution of 40% dimethoate emulsifiable concentrate; second, spray with a 1000-1500 times diluted solution of menazon (miezayin) to kill them.
(4) Cabbage caterpillars. Their larvae bite and eat the leaves, causing holes and gaps. In severe cases, entire leaves are eaten up. During the occurrence period, spray with a 1500 times diluted solution of 90% trichlorfon or a 1000 times diluted solution of dichlorvos to kill them.
V. Harvesting and Processing. When grown from tubers, harvest from late September to November of the same year. In the Jiangsu-Zhejiang area, harvest is carried out from late September to mid-October; in Sichuan and Guangxi, from October to November. If harvested too late, the skin is not easy to remove. After the aboveground leaves of the plants turn yellow and withered, choose a sunny day and use a small four-tooth iron rake to shallowly and finely turn the bed surface, picking out corms with a transverse diameter of 10 mm or more for processing as medicinal material. Corms smaller than 10 mm are left in the ground to continue growing and are harvested after they grow larger the following year. In plots with loose soil, the soil layer containing the growing corms can be shoveled into a sieve to sieve out the corms. Stack the harvested Pinellia ternata corms indoors for 10-15 days at a thickness of 40-50 cm. After they ferment (when the outer skin is slightly rotted and easy to remove, but do not stack too long, lest the corms rot), put them into bamboo baskets and place them in a flowing water area. Wear straw sandals or tall rubber boots and continuously tread on them in the bamboo baskets to remove the coarse outer skin of the corms. Then rinse off impurities, air-dry the surface moisture, and place them in a sulfur cabinet (furnace) to fumigate with sulfur until thoroughly penetrated. Take them out and sun-dry them. If cloudy and rainy days occur, continue to put them in the cabinet (furnace) for sulfur fumigation, and sun-dry them again when the weather is clear. The commercial product is considered high quality when it is fully dry, whole, full of powder and firm, with the skin completely removed, the surface light yellow, the flesh pure white, and the transverse diameter 10 mm or more.