Key Techniques for High-Quality and High-Yield Cultivation of Pinellia ternata
1. Site selection and land preparation Creating a good growing and cultivation environment is the basic condition for high yield of Pinellia ternata. Under long-term wild ecological conditions, Pinellia ternata has developed characteristics of preferring a mild and humid climate and shaded environment, fearing high temperatures, drought and intense sunlight, and being able to tolerate cold. Therefore, the planting site for Pinellia ternata should be selected in sandy loam soil on sunny-facing terraces, terraced fields or gentle slopes close to a water source. The soil is required to be loose, fertile and well-drained. The previous crop is best as corn or rapeseed. After selecting the site, in combination with autumn plowing and land preparation, apply per mu 2000kg of decomposed chicken manure or other high-quality farm manure, and 50kg of superphosphate or 15kg of diammonium phosphate. Before sowing, finely prepare the land and make beds. The bed width is 1.5m, the bed length is determined according to the terrain, and the bed ridge height is 20cm. Generally, the cultivation bed is prepared as two parallel rows, and a 40cm-wide irrigation furrow is made on the side of the wide bed ridge.
2. Strict seed selection Scientific seed selection is the key to high yield of Pinellia ternata. Many years of production practice have proven that wild Pinellia ternata from cool, shaded areas at an altitude above 1650 meters has resistance to degeneration, good seed characteristics and fewer carried pathogens. It shows high yield, disease resistance, strong stress resistance and good quality. It can be harvested in the same year it is cultivated, with quick results. In late August, when wild Pinellia ternata matures and is extensively dug, promptly purchase wild Pinellia ternata tubers about 1cm in diameter from high mountain areas, dry them in the sun, select them carefully, and properly store them in a cool place for future use as seed. Absolutely avoid using artificially cultivated Pinellia ternata tubers as seed.
3. Fine sowing Strictly control sowing quality and promote uniform, even and early emergence of Pinellia ternata seedlings; this is the foundation for high yield in artificial cultivation of Pinellia ternata. In our county, Pinellia ternata is generally sown in late autumn, with the suitable sowing period in late October when the temperature steadily passes 8°C. Before sowing, if the soil is relatively dry, irrigate once thoroughly to ensure sufficient bottom soil moisture. At sowing, grade the seeds by size, remove diseased and rotten tubers, mix the seeds with 10 million agricultural streptomycin or 50% carbendazim at 0.3% of the seed amount, pile them for 12 hours, and then sow. Sowing method: shovel out the 10cm-thick soil in the first sowing bed and pile it at the edge of the field, level the bed bottom, evenly broadcast the seeds in the bed at a seeding rate of 250kg per mu, and place 2-3 upright 10cm-high sowing depth limit boards in the bed. Then shovel up the 10cm-thick soil from the second small bed and evenly cover the first sowing bed. In combination with covering soil, carbendazim can be used for soil disinfection. The covering depth should not exceed the limit boards. Remove the limit boards and rake fine and level. In this way, after sowing the second bed, cover it with soil shoveled from the third bed, and so on, until the soil shoveled from the first bed is used to cover the last bed and sowing is completed.
4. Field management Strengthening field management is the fundamental measure to ensure high yield of Pinellia ternata. The key to Pinellia ternata cultivation is to manage three aspects well: water and fertilizer, weeding, and pest and disease control.
4.1 Water and fertilizer management. Pinellia ternata has a shallow root system, prefers moisture and fears drought, and prefers fertilizer. Lack of water can easily cause aboveground stems and leaves to wither. Before emergence in early spring, it must be irrigated once thoroughly, and then timely and frequent intertillage and soil loosening should be carried out to increase soil temperature and promote early emergence. After mid-May, the temperature gradually rises. When it is dry and rainless, water once every 7-10 days. Especially in the high-temperature weather of July, pay even more attention to watering well, often keep the soil moist, and prevent drought-induced seedling collapse. Fertilization should be combined with irrigation. After full emergence in early April and in late May, apply per mu 1000kg of human feces and urine or 10kg of diammonium phosphate, and during the growth period apply foliar fertilizer 2-3 times with monopotassium phosphate and Liguomei.
4.2 Intertillage and weeding. Pinellia ternata seedlings are weak and the root system is small, with poor growth vigor. Weeds easily grow and form a weed infestation, competing for water and fertilizer and seriously affecting Pinellia ternata yield. It is necessary to frequently carry out intertillage and weeding before the seedlings close the rows. The intertillage depth should not exceed 5cm to avoid injuring seedlings and roots. Throughout the entire growth period of Pinellia ternata, weeds should be pulled as soon as they appear, keeping the field clean and free of weeds, and strictly preventing weed infestation.
4.3 Pest and disease control. The common diseases of Pinellia ternata mainly include leaf spot disease and rot disease; the main pests mainly include red hawk moths and underground pests. Leaf spot disease occurs from late May to early July. Diseased leaves show purple-brown spots, and in severe cases the spots cover the entire leaf, causing the leaves to curl, scorch and die. In the early stage of disease, spray with 1:1:100 Bordeaux mixture for control, or alternately spray with Diwuban, phosethyl-Al manganese zinc, and carbendazim, for 2-3 control applications. Rot disease occurs from mid-June to early August in rainy and high-temperature seasons. The aboveground stems and leaves turn yellow, collapse and die, and the underground tubers rot. It can be controlled by spraying or root drenching with 70% Meibang Zhiwei, 70% thiophanate-methyl, Kuhuangqing, or new streptomycin. Red hawk moth larvae bite and feed on leaves and have a large appetite. When severe, they can eat all the leaves. It can be controlled by spraying a 1000-fold solution of a mixture of 50% dichlorvos emulsifiable concentrate and 20% dimethoate emulsifiable concentrate.
5. Timely harvesting Timely harvesting and fine processing are important measures to ensure the quality of Pinellia ternata. Whether Pinellia ternata is harvested at the right time and whether processing is fine directly affects the commercial value of the tubers. If harvested too early, the tubers are small and tender, and the yield is low; if too late, the inner epidermis of the tubers becomes coarse, old and spotted, forming oily seeds. It is best to harvest in late August after the stems and leaves turn yellow and wither. When harvesting, choose sunny days and carefully dig and pick the Pinellia ternata tubers to prevent damage. Grade the harvested Pinellia ternata into large, medium and small sizes, put them into gunny bags, wear long rubber boots to tread off the outer skin, rinse clean with water, and dry promptly in the sun to obtain raw Pinellia ternata.