How to Grow Chinese Yam for High Yield? Key Cultivation Techniques Explained

Chinese yam, also known as Huai yam, among other names. Its underground rhizome is used medicinally; it has the effects of strengthening the spleen and nourishing the stomach, tonifying the lungs and benefiting the kidneys, and stopping diarrhea. It is mainly used to treat diarrhea due to spleen deficiency, chronic enteritis, asthma and cough due to lung deficiency, chronic nephritis, diabetes, and other conditions. It is mainly produced in Henan, Shaanxi, Shandong, Hebei, Shaanxi, and other places. It is now cultivated in most parts of the country.

Morphological characteristics: It is a perennial twining herb of the Dioscoreaceae family. The rhizome is thick and fleshy, slightly cylindrical, growing vertically, up to 1 m long and 2-7 cm in diameter, with a grayish-brown outer skin and fibrous roots. The stem is slender, trailing, usually purple, angular, smooth and hairless. The leaves are opposite or in whorls of 3, and bulbils (called bulblets) often grow in the leaf axils; the leaf blade shape is highly variable, triangular, ovate to triangular broadly ovate, 3.5-7 cm long and 2-4.5 cm wide, usually with 3 auriculate lobes, the central lobe gradually pointed at the tip, the two lateral lobes rounded-auriculate, the base hastate, truncate, deeply cordate, or broadly cordate, smooth and hairless on both sides; veins 7-9; petiole slender, 1.5-3.5 cm long. Flowers unisexual, dioecious, very small, yellow-green, in spikes; male spikes upright, 2 to several clustered in the leaf axils, the rachis mostly zigzag, flowers small, nearly sessile, bracts triangular-ovate, perianth 6, elliptical, blunt at the tip, stamens 6, filaments very short; female spikes drooping, each flower with 2 bracts of unequal size at the base, bracts broadly ovate with a long tapering tip; perianth 6; ovary inferior, oblong, 3-locular, stigma 3-cleft. The capsule has 3 wings, the wings nearly as long as wide. Seeds flat and ovate, with broad wings.

I. Growth habits: Chinese yam prefers a sunny, warm, and humid environment. It likes water and fertilizer and is afraid of drought. It is suitable for cultivation in deep, loose, fertile sandy loam rich in organic matter. Saline-alkali land and low-lying land are not suitable for cultivation.

II. Land preparation and fertilization: Chinese yam is a deep-rooted crop, so choose a field with high terrain and good drainage, and plow deeply and harrow carefully. Apply sufficient base fertilizer in combination with land preparation: 5000 kg of farmyard manure, 50 kg of cake fertilizer, 20 kg of urea, and 50 kg of phosphorus and potassium fertilizer per mu. Then make raised beds and wait for sowing.

III. Sowing: In Chinese yam production, propagation by yam heads is used. Around Frost's Descent, cut 15 cm yam heads from the upper part of the dug-out underground tubers with yam heads attached, dry them slightly to heal the wounds, and store them in a cool place (store in a cellar in winter). Plant them on the bed surface around Grain Rain of the following year. The row and plant spacing is 40×15 cm. For propagation by aerial tubers, sow the aerial tubers in rows on the bed around Pure Brightness. The row and plant spacing is 30×10 cm. Dig them out after autumn, then transplant them to the field according to the yam head propagation method.

IV. Field management: After Chinese yam emerges, attention should be paid to cultivating and weeding. For large-scale planting, a herbicide for medicinal fields should be used for soil treatment before emergence, which can effectively control various weeds. When the seedlings are 10 cm high, trellises should be set up to let the yam vines twine, so as to facilitate ventilation and light penetration. Because Chinese yam likes water and fertilizer, water and topdress in a timely manner to keep the soil moist and promote growth. During continuous rainy weather, drainage should also be carried out in a timely manner to prevent waterlogging and root rot.

V. Pest and disease control: The main disease of Chinese yam is anthracnose, which occurs from June to August and seriously damages stems and leaves; it can be controlled with 65% mancozeb in the early stage of the disease. Powdery mildew is controlled with triadimefon. Underground pests are controlled with phoxim.

VI. Harvesting and processing: For Chinese yam propagated by yam heads, dig it after autumn when the aboveground stems and leaves wither. Before digging, first cut off the aboveground stems and leaves, and collect the aerial tubers for later use. Then dig out the underground rhizomes. Wash off the soil, scrape off the outer skin with a blade, fumigate with sulfur, and dry in the sun before selling as medicine. The yield per mu is 400 kg. Those with a firm texture, white color, abundant powder, and dryness are considered the best quality.