Six key selection points for high-yield cultivation of the Chinese medicinal herb Pinellia ternata
I. Strictly select the soil geology
Growing in the soilPinellia ternataThe tubers have relatively strict requirements for the soil geology: they are afraid of both acid and alkali, afraid of both sand and clay, require fertile soil yet restrict the use of chemical fertilizers, and prefer moist soil in the early stage and dry soil in the later stage. Because Pinellia ternata growth involves these four contradictory soil characteristics, the plot for planting Pinellia ternata should be selected as moist and fertile sandy soil with strong water and fertilizer retention, loose texture, good drainage and irrigation, and a neutral reaction; semi-shaded, semi-sunny gentle-slope mountain land and woodlands or orchards with certain light conditions can also be chosen for planting. The soil geology must meet the following: pH value between 6.5 and 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 planting, the reasonable selection of terrain is directly related to the high quality and high yield of Pinellia ternata. The terrain of the Pinellia ternata planting site should meet the following: in low mountains and hilly land, a semi-shaded, semi-sunny gentle hillside should be selected, with a slope of 10 degrees to 30 degrees 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 survey of the surrounding environment should also be conducted: there should be no pollution sources within 1000 m, the site should be more than 100 m from major traffic roads, and the irrigation water used should comply with the national farmland irrigation water standards. Correctly and reasonably selecting the terrain is the foundation for high yield of Pinellia ternata, and it must not be done carelessly.
III. Correctly select superior 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 officially nationally approved superior variety. According to the author's nearly 20 years of cultivation research and observation on Pinellia ternata, based solely on leaf type, Pinellia ternata can be divided into several types: bamboo-leaf type, bamboo-like-leaf type, willow-leaf type (which the author calls "narrow three-leaf"), apricot-leaf type, and palm-leaf type. The bamboo-leaf type and apricot-leaf type are relatively widely distributed and have been found in all major Pinellia ternata production areas nationwide; 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; "narrow three-leaf" Pinellia ternata is mainly native to Shandong. Comparing and screening among the above different leaf types of Pinellia ternata, the "narrow three-leaf" Pinellia ternata native to Heze, Shandong and Fengxian, Jiangsu has the highest yield and relatively good quality, with vigorous growth, many stem and leaf tillers, large and thick leaves, relatively strong photosynthesis and resistance, early and numerous bulbils, and large, round and neat commercial individuals, making it currently a superior variety for artificial cultivation of Pinellia ternata.
IV. Carefully select chemicals for seed soaking
For artificially cultivated Pinellia ternata, pests and diseases should be prevented primarily and treated supplementarily; once large-area pests and diseases occur during the growing period, treatment is quite troublesome, not only affecting the growth of Pinellia ternata but also easily producing pesticide residues and increasing planting costs, so treating the seed stems before sowing is very important. However, in selecting the chemicals, doses and methods for soaking and mixing the seed stems, it is necessary to correctly choose high-efficiency, low-toxicity, low-residue fungicides and seed-dressing chemicals; the dosage and treatment methods must be scientific and reasonable, just right, and must not be used indiscriminately or excessively, so as to avoid counterproductive effects and unnecessary losses.
V. Select the planting time
Pinellia ternata can grow in most provinces and regions of our country. 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, it can be cultivated in late autumn or winter; in the Huang-Huai region, the most suitable planting time is from late February to early March (from 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 underground temperature at 5 cm stabilizes at 5°C to 7°C, which is the best sowing time. Sowing as early as possible and taking effective measures can make the leaf stalks of Pinellia ternata grow horizontally in the soil and produce bulbils; the bulbils formed in the soil are large and can quickly take root and sprout to form a new plant, increasing the propagation coefficient, which is one of the important technical measures for high-yield cultivation of Pinellia ternata.
VI. Select the planting method
On the prepared sowing bed surface that has been finely leveled and raked flat, open horizontal furrows for row sowing. Sow the graded large and small seed stems separately: for grade-one seed stems, the row and plant spacing is wider (30 cm) and sowing is deeper (7 to 9 cm); and so on by analogy, for grade-four seed stems, the row and plant spacing is denser (15 cm) and planting is shallower (3 to 4 cm). 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-and-soil ash, etc., and finally cover with soil slightly lower than the ground surface (semi-mechanized sowing can also be used, completed in one pass, which can increase efficiency by 80%). Because there are many weeds during the growth period of Pinellia ternata, especially at the seedling stage, when often no Pinellia ternata can be seen but only grass, immediately after Pinellia ternata sowing is completed, spray the special herbicide for Pinellia ternata and immediately cover with plastic film, which can effectively prevent weed damage, especially with a control effect of up to 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 bed.