Detailed Explanation of Pinellia ternata Planting and Cultivation Techniques and Management Methods

I. Growth Characteristics

Pinellia ternata prefers warm, humid, semi-shaded, semi-sunny environments, and is suitable for planting in loose, fertile sandy soil with a pH value of 5.6--6.4; Pinellia ternata is afraid of heat and cold, and the suitable growth temperature is 15--25°C. Above 26°C it begins summer dormancy and seedling collapse, and below 13°C it overwinters and withers.

Pinellia ternata sprouts 3 times per year: the first time is from late March to early April, the second time is in early to mid-June, and the third time is in early to mid-September. The initial stage of bulbil germination is in early April, the peak is in mid-April, and the maturity period is from late April to early May. Each growth period is 50--60 days.

The propagation of Pinellia ternata includes tuber propagation, bulbil propagation and seed propagation, but seed propagation has a low germination rate and a relatively long growth period. Tuber propagation uses the small tubers remaining after screening commercial Pinellia ternata as seed, and its advantage is a relatively short growth cycle; generally sown in spring, it can be harvested by the end of summer of the same year. Bulbil propagation uses bulbils as seed, which are abundant in number, reliable in germination, and earlier in maturity, making it the main propagation method for developing Pinellia ternata production.

II. Cultivation Techniques

(1) Site Selection and Land Preparation

In view of the living habits of Pinellia ternata, which prefers warmth, fertilizer and moisture, and fears drought, waterlogging and high temperatures, warm and humid sandy loam with good drainage and irrigation conditions and loose fertility should be selected for planting. In the winter of the previous year, deep ploughing and freezing of the soil should be carried out to promote soil freeze-thaw weathering. After the beginning of spring, the land should be leveled, and 3000 kg of farmyard manure and 30 kg of superphosphate per mu should be applied as base fertilizer, then ploughed, harrowed and leveled, and beds made ready for planting. In addition, continuous cropping should be strictly avoided in Pinellia ternata cultivation. Generally, after growing one season of Pinellia ternata, at least 3 years of rotating other crops are required before it can be planted again; otherwise, it will lead to reduced yields year after year, or even no harvest at all.

(2) Timely Sowing and Reasonable Close Planting

Pinellia ternata can be sown in spring, summer and autumn. For summer and autumn sowing, because the seed stems overwinter in the field, they are susceptible to adverse climate and pest and disease damage, and occupy the land for an extra half year; therefore, field production generally adopts spring sowing, which can both avoid the adverse factors of the previous crop and allow timely adjustment of the planting area according to market demand dynamics of that year. Spring sowing is generally carried out after the soil thaws in early spring, in fields that have already been ploughed, harrowed and made into beds, by drilling. The plant and row spacing is about 3 cm each, and the sowing depth is about 10.5 cm.

(3) Reasonable Application of Fertilizer

Pinellia ternata prefers fertilizer, so in addition to applying sufficient base fertilizer, fertilizer should also be topdressed according to the land and the seedlings to promote their robust growth. After the seedlings emerge uniformly in early to mid-April, 1000 kg of dilute manure water per mu can be applied to promote early seedling development; around late May, when all the bulbils have formed, gradually expanded and turned reddish-brown, 10 kg of urea per mu should be applied together with earthing up; after seedling collapse in mid-July, when the daughter Pinellia ternata exposes new buds and the mother Pinellia ternata regrows new roots, 1500 kg of dilute manure water should be splashed on to promote re-greening; in early to mid-September, when Pinellia ternata has full and uniform seedlings, 10 kg of urea, 20 kg of superphosphate and 20 kg of cake fertilizer per mu should be mixed evenly with soil and spread uniformly on the surface, serving to earth up and promote grain filling.

(4) Timely Irrigation and Drainage to Reduce Waterlogging

Pinellia ternata prefers moisture but fears waterlogging. Therefore, during its growth period, the soil must be kept moist while avoiding water accumulation and waterlogging. In dry weather, furrow irrigation should be carried out in time to meet the water needs of Pinellia ternata growth; in rainy weather, ditches should be opened in time for drainage to prevent waterlogging and reduce waterlogging.

(5) Control of Diseases, Pests and Weeds

Pinellia ternata plants are relatively small, with underdeveloped root systems, and their ability to compete with weeds for fertilizer and water is relatively poor, so soil should be loosened and weeds removed in time to prevent weeds from overwhelming the seedlings. The main diseases of Pinellia ternata include leaf spot disease and viral disease. For the control of leaf spot disease, at the early stage of the disease, spray 1:1:120 Bordeaux mixture or 65% zineb 500-fold solution, once every 7 days, spraying 2--3 times in succession. To control viral disease: first, disinfect the soil before sowing and thoroughly control insect pests; second, select disease-free mother plants for seed retention; third, promptly remove diseased plants and burn or bury them in a centralized manner. The main pest harming Pinellia ternata is the red hawk moth, which occurs in summer, with larvae damaging leaves, biting them into notches or eating them bare. The control method is to spray 90% trichlorfon 800-fold solution at the young larval stage, or to carry out manual capture.

(6) Earthing Up and Flower Removal

In order to retain water and fertilizer and protect the bulbils exposed on the soil surface, soil should be earthed up around the plant roots 1--2 times. For plants not retained for seed, flower buds should be removed in time to reduce nutrient consumption, increase tuber weight and increase yield.

(7) Harvesting

After frost, when the aboveground parts wither, most of the bulbils have matured, and harvesting should be carried out in time. If dug too early, some that should be mature are not yet mature, which will affect yield and quality; if dug too late, the underground tubers and bulbils, after a short dormant period, begin to sprout and grow again, which will also affect yield and quality. When digging, it is advisable to take 2--3-year-old tubers, cut the qualified large tubers from the rhizome part, and the remaining cut parts with many buds can be used as seed.