Six Selection Points for High-Yield Cultivation of Pinellia ternata
I. Strictly Select the Soil Conditions
The tubers of Pinellia ternata growing in the soil have fairly strict requirements for soil conditions. They are afraid of both acidity and alkalinity, afraid of both sand and clay, require fertile soil yet are limited in the use of chemical fertilizers, and prefer moist soil in the early stage and dry soil in the later stage. Based on these four contradictory characteristics of Pinellia ternata's growth requirements regarding soil, the plot for planting Pinellia ternata should be selected as moist and fertile sandy loam with strong water and fertilizer retention capacity, loose texture, good drainage and irrigation, and a neutral reaction. Semi-shaded, semi-sunny gentle slope mountain land, as well as woodland and orchards with certain lighting conditions, can also be chosen for planting. The soil conditions must meet the following: pH value between 6.5-7.5, neither sandy nor clayey, and organic matter content greater than 1.2.
II. Flexibly Select the Terrain
The selection of terrain is often the issue most easily overlooked by Pinellia ternata growers, who generally consider it unimportant; in fact, for Pinellia ternata cultivation, the reasonable selection of terrain is directly related to high quality and high yield. The terrain of the Pinellia ternata planting site should meet the following: in low mountains and ridge areas, a semi-shaded, semi-sunny gentle slope should be selected, with a slope of 10-30 being best; when planting Pinellia ternata in plain areas, a plot that can be irrigated and drained and has high, dry terrain must be selected, and drainage ditches must be prepared before planting. In addition, an on-site investigation of the surrounding environment should be conducted: there should be no pollution sources within 1000 m, the distance from major traffic roads should be more than 100 m, and the irrigation water used should meet the national farmland irrigation water standards. Correctly and reasonably selecting the terrain is the foundation for high yield of Pinellia ternata, and one must never be careless.
III. Correctly Select Good Varieties
Because artificial cultivation of Pinellia ternata began in the mid-1980s, the time has been relatively short, and coupled with the characteristics of Pinellia ternata, price, and other factors, as of now there is still no improved variety that has been formally approved by the state. According to more than twenty years of field practice and observation in Pinellia ternata cultivation by the Heze City Runkang Chinese Medicinal Materials Research Institute in Shandong, based solely on leaf type, Pinellia ternata can be divided into several strains such as bamboo-leaf type, bamboo-like-leaf type, willow-leaf type, peach-leaf type (named by the research institute as narrow three-leaf), apricot-leaf type, and palm-leaf type. Among wild Pinellia ternata strains, the bamboo-leaf type and apricot-leaf type are more widely distributed and have been found in all major wild production areas of Pinellia ternata across the country; the bamboo-like-leaf type and palm-leaf type are distributed in parts of Guizhou, Yunnan, Sichuan, Hunan, and Jiangxi provinces and in the Yangtze River basin; the narrow three-leaf Pinellia ternata, that is, the peach-leaf type Pinellia ternata, originates mainly from Heze in Shandong and surrounding areas, and has now been introduced and expanded to parts of south-central Shanxi, north-central Henan, Gansu, Shaanxi, Hebei, Anhui, Jiangsu, Sichuan, Guizhou, Yunnan, and other provinces. From comparative screening among the different leaf types of Pinellia ternata seed stems above, the narrow three-leaf Pinellia ternata native to Heze in Shandong and Fengxian in Jiangsu has the highest yield and relatively good quality, with vigorous growth, many tillers on stems and leaves, large and thick leaves, strong photosynthesis and resistance, and high resistance to rot disease and high-temperature withering and lodging; the bulbils form early and in large numbers, and the commercial individuals are large and round, so it can serve as a good variety for Pinellia ternata planting and is currently the most excellent strain for artificial Pinellia ternata cultivation.
IV. Carefully Select Chemical Agents for Seed Soaking
For artificially cultivated Pinellia ternata, prevention should be the main approach to pests and diseases, with treatment as a supplement. Once large-scale pests and diseases occur during the growing period, treatment becomes quite troublesome; it not only affects the growth of Pinellia ternata, but also easily produces pesticide residues and increases cultivation costs. Therefore, treating the seed stems before sowing is very important. However, in the selection of chemical agents, dosage, and methods for soaking and dressing seed stems, one must correctly choose fungicides and seed-dressing agents that are efficient, low-toxicity, and low-residue; the dosage and treatment methods must be scientific and reasonable, just right, and one must never use them indiscriminately or excessively, so as to avoid the opposite effect and cause unnecessary losses.
V. Select the Planting Time
Pinellia ternata can grow in most provinces and regions of our country. From Guangdong in the south to Jilin in the north, from Xining in the west to Shandong in the east. In order to maximize the growth time of Pinellia ternata and improve yield and quality, the best sowing time should be selected according to different regions. In southern provinces and regions without frost or with a short frost period, cultivation can be done in late autumn or winter; the most suitable planting time in the Huang-Huai region is from late February to early March (Yushui to Jingzhe); in some areas of the northwest and northeast, the planting time can be appropriately postponed. In short, the most suitable planting time for Pinellia ternata in each province and region is, based on local actual measurement, when the 5 cm ground temperature stabilizes at 5-7 degrees, which is the best sowing time. Sowing as early as possible and adopting effective measures can cause the leaf stalks of Pinellia ternata to spread horizontally in the soil and grow bulbils; the bulbils formed in the soil are large and can quickly take root and sprout, forming a new plant, increasing the propagation coefficient, and this is one of the important technical measures for high-yield cultivation of Pinellia ternata.
VI. Select the Planting Method
On the prepared seedbed surface that has been finely leveled and raked, open horizontal furrows for row sowing. Sow the graded large and small seed stems separately. For grade-one seed stems, the row spacing and plant spacing are wider (30X7), and sowing is deeper (7-9); and so on by analogy, for grade-four seed stems, the row spacing and plant spacing are denser (15X2), and planting is shallower (3-4). After sowing, apply a layer of mixed fertilizer soil on top, made by evenly mixing decomposed compost and barnyard manure with human and livestock manure, grass soil ash, etc., and finally cover with soil slightly lower than the ground surface (a current new technology of semi-mechanized sowing can also be used, completing it in one operation, which can increase efficiency by 80%). Because there are many weeds during the growth period of Pinellia ternata, especially at the seedling stage, often only grass can be seen and not Pinellia ternata, so after sowing of Pinellia ternata is completed, immediately spray a special herbicide for Pinellia ternata and immediately cover with plastic film, which can effectively prevent weed damage, especially with a control effect of 100% against grass-family weeds. After spraying the herbicide, cover immediately with plastic film. The plastic film used can be ordinary agricultural plastic film (0.014 mm thick) or high-density plastic film (0.008 mm). The width of the plastic film is chosen according to the width of the seedbed. Cover the film with three people in one group. First open a ditch about 8 cm deep on each outer side of the two ridges of the seedbed, with consistent depth. One person spreads the film, and two people simultaneously pull the plastic film tight on both sides. After it is flat, press the film edges into the ditches with soil, applying even force so that the film is flat and tightly attached to the seedbed ridges, and press firmly with soil.