Key Techniques for High-Yield Cultivation of Arisaema Under Forest Canopy

High-Yield Cultivation Techniques for Arisaema Under Forest Canopy

Arisaema is a perennial shade-and-moisture-loving herbaceous plant and a precious medicinal plant, mainly distributed in Hebei, Henan, Shandong, Anhui, Hunan and other places in China, mostly growing in valleys, riverbanks, shrublands, grasslands, wastelands and under forest at altitudes of 50-1200 m. The spherical tubers of Arisaema have very high medicinal value, with the functions of dispelling wind and calming convulsions, and resolving phlegm and dissipating nodules, and have relatively high economic value and development prospects. Wild resources are now becoming increasingly scarce. In order to explore cultivation techniques for Arisaema under forest canopy, the author selected local wild provenances in the southwestern region of Hunan, made full use of the understory space, adopted advanced pure ecological high-yield cultivation techniques, and planted Arisaema under forest with a canopy density of 0.4-0.7, adopting two treatments, fertilized and unfertilized, to test the effects on the growth and yield of Arisaema.

Overview of the Trial Area

The trial area was located in Yanjing Village, Tangjiafang Town, Suining County, Hunan Province. The trial area is located at the middle and lower part of a hillside at an altitude of 800-1000 m, where transportation is convenient and the canopy density is above 0.6. It belongs to the mid-subtropical monsoon humid climate zone, with a long warm period and a short severe cold period, an annual average temperature of 17.5°C, a frost-free period of 256-289 days, annual sunshine hours of 1782-1875 hours, and an annual average precipitation of 14500-16800 mm, of which 67% is concentrated from April to October. The soil in the trial area is yellow soil developed from slate, with deep soil layers, a pH value of 5-6, and medium soil fertility.

Material Selection

Local wild Arisaema was used as the experimental material, and robust, pest- and disease-free superior large tuber segments were selected. Two forest plots under the same conditions were selected for the trial, each with an area of 2000 sq m, at an altitude of 800 m, with moist soil, well-drained sandy loam, and understory space with a canopy density of 0.4-0.7. Two treatment methods, pure natural and artificial high-yield cultivation, were selected to carry out the understory cultivation trial of Arisaema.

Planting Management Techniques

Land preparation and soil treatment. Land preparation was carried out by strip full reclamation. According to the row spacing, horizontal terraced strips were opened along the contour around the mountain, with the outer side high and the inner side low, and a strip width of about 1.0 m for making beds. The bed surface was shaped like a turtle shell, and drainage ditches were opened on the inner side and both sides of the bed, with a drainage ditch depth of 30 cm and a width of 20 cm. At the same time, weeds, small stones and other debris were removed. The soil was turned and deeply dug to 20 cm.

Fertilization. On the opened strip forest land, in combination with land preparation, 2500 kg of decomposed stable manure or compost was applied per 667 sq m, turned into the soil as base fertilizer, and before planting, 1-2 more times of reclamation and mixing were carried out. Holes were dug at a plant-row spacing of 15 x 30 cm for sowing.

Planting time. The sowing time was November to December of that year. When the ground temperature was stable at 8 degrees, the Arisaema seed tubers were soaked and pregerminated 15 days in advance (or they could be sown directly without pregermination), and after sowing, plastic film was used to cover the ground (or no plastic film was used).

Planting method. First, after fertilizing and plowing the soil, high beds 100 cm wide were made, ready for sowing. Second, the large Arisaema seed tubers were cut with a knife into individual seed tubers. When cutting with a knife, ensure that each cut seed tuber has a bud eye, treat the wounds with plant ash, and sow immediately; they must not be left for a long time. Finally, sow one seed tuber per hole, with a row spacing of 30 cm, a plant spacing of 15 cm, and a sowing depth of 5 cm. After sowing, cover with soil level with the ground.

Forest land management. Forest land management after planting creates superior environmental conditions for the growth of Arisaema and meets its requirements for fertilizer and water during growth and development. This is a key measure to ensure high and stable yield.

Soil, fertilizer and water management. When the seedlings are about 6 cm tall, carry out the first loosening of soil and weeding. Weeding should be shallow rather than deep; it is enough to loosen the surface soil. After hoeing, apply ecological organic fertilizer as a top dressing, 30 kg per 667 sq m. The second loosening of soil and weeding is around July, and the soil can be loosened somewhat more deeply. Open furrows between rows and apply manure, 1500-2000 kg per 667 sq m. When the temperature is high, water frequently to maintain sufficient moisture and keep the soil moist. In the rainy season, pay attention to drainage to prevent water accumulation.

Replanting. When missing plants or diseased plants are found, replant with strong seedlings of the same age, and strengthen management so that the replanted seedlings and the forest land seedlings grow in a balanced way.

Flower removal. For land not kept for seed production, in order to reduce nutrient consumption and increase yield, in May to June, when the spadix inflorescence of Arisaema emerges from the sheath-like spathe, cut it off as soon as possible.

Pest and disease control. Give priority to biological control to improve disease and pest resistance. When Arisaema is affected by viral disease, yellow irregular lesions appear on the leaves, and the leaves become deformed, shrunken, curled and malformed, causing poor plant growth and later leaf death. Control methods: choose disease-resistant varieties for planting; increase the application of phosphorus and potassium fertilizers to enhance the plant's own disease resistance; fully apply biological control techniques and use virus-antagonistic methods to control viral diseases. Common pests of Arisaema include red hawk moths, red spider mites, etc. Give priority to manual and physical control methods, cultivate natural enemies of pests, and reduce pest damage.

Harvesting and processing. Harvest from late September to early October. On a sunny day, dig up the tubers, remove soil and fibrous roots, put them in baskets, place them in water and brush and wash repeatedly, scrape off the outer skin with a knife, and dry in the sun.

Except that no fertilization was carried out, the other management technical measures in the unfertilized trial plot were all the same [Jishan Huayao].

Practice shows that in zonal climate areas similar to Suining County, planting Arisaema under forest with a canopy density of 0.4-0.7, at 2 years old, the yield without fertilization was 0.4 kg per sq m, and with fertilization was 0.6 kg per sq m; at 3 years old, the yield without fertilization was 0.7 kg per sq m, and with fertilization was 1.12 kg per sq m.

For planting Arisaema under forest in mountainous areas, fine forest land management techniques are the key to high and stable yield. Planting Arisaema under forest has good results, with few pests and diseases, high content of medicinal active components in the product, and good quality, and fertilization increases the yield by 30% compared with no fertilization. Pure ecological planting under forest ensures the medicinal quality of Arisaema.

The spherical tubers of Arisaema have very high medicinal value, with the functions of dispelling wind and calming convulsions, and resolving phlegm and dissipating nodules, and have relatively high economic value and development prospects.