How to grow Chinese yam? Master these methods and technical points
Chinese yam can be eaten as a vegetable and also used medicinally. It grows on hillsides at an altitude of 150-1500 m, in valley forests, in thickets or among weeds by streams and roadsides. So, how do you grow Chinese yam?
1. Land preparation
Chinese yam should be grown in a 2-3 year rotation. In addition to fertilizing and plowing, land preparation mainly involves digging loose trenches for the tubers to extend downward, generally more than 1 m deep, 20-25 cm wide, with 80-100 cm between trenches. Digging trenches by hand is rather time-consuming, so it is generally done before winter. When backfilling soil after digging, be careful not to disturb the order of the soil layers. Using a dedicated trench digger is more efficient and can be done one month before sowing.
2. Planting
Generally, once the 5 cm soil temperature steadily passes 9-10°C, planting can begin. In southern Sichuan and the Guangdong and Guangxi regions of China, planting can be done in March; in Sichuan, from late March to April; in North China, in mid-to-late April; and in Northeast China, in early May. The planting method is to open a furrow 8-10 cm deep with a hoe, place the seed tubers flat lengthwise in the furrow, and spread them evenly with the bud tips as the reference. The sowing density is generally 37,500-45,000 plants/ha, with a plant spacing of 25-30 cm, and the row spacing is the trench spacing. Before sowing, dig a sowing furrow about 10 cm deep directly above the already dug trench, place the seed pieces flat along the ridge in the furrow according to the plant spacing, with the upper ends of the seed pieces facing the same direction. After arranging them, cover with soil and pat smooth.
3. Pruning and trellising
Chinese yam is a climbing plant. Before the seedlings reach 30 cm in height, trellises must be set up, with a height of 1.5-1.7 cm and the trellis material inserted 20-30 cm into the soil. A-frame trellises or four-corner trellises are commonly used. When the seed pieces sprout, they generally send out 1 main stem, but sometimes more than 2, correspondingly producing 2-3 tubers that compete with each other for nutrients, making each tuber thin and small and affecting high-quality production. After emergence, the excess vines should be removed immediately, leaving only 1 thick main stem. Some varieties have too many lateral branches, and in the mid-to-late stage the lower lateral branches should be appropriately removed, as well as the tips of the main stem and lateral branches. A large number of bulbils forming affects tuber growth, and they can generally be controlled at 1500-2250 kg/ha.
4. Fertilization
Chinese yam has a high fertilizer requirement. For every 1000 kg of tubers produced, it absorbs about 4.32 kg of pure nitrogen, 1.07 kg of phosphorus pentoxide, and 5.38 kg of potassium oxide. Chinese yam is sensitive to chlorine, so potassium chloride should not be used, and emphasis should be placed on applying heavy organic fertilizer. Generally, for high-yield fields, the base fertilizer per hectare requires 45-75 cubic m of decomposed organic fertilizer, 350-400 kg of diammonium phosphate, 250-300 kg of urea, and about 150 kg of potassium sulfate, applied broadcast in the field before land preparation and plowed into a soil layer about 25 cm deep. When entering the vigorous growth period of stems, leaves, and tubers, apply 1 heavy topdressing. Apply about 400 kg of nitrogen, phosphorus, and potassium compound fertilizer per hectare, and water.
5. Irrigation
In the early stage, as long as the soil below 5 cm of the surface is moist, there is no need to water. Generally, the first watering is done when the seedlings are about 1 m tall; about 20 days later, when entering the vigorous branch and leaf growth period, water a second time. The first 2 waterings should be light; never use flood irrigation. About 1 month after the second watering, when entering the rapid tuber enlargement period, if the soil is dry, water thoroughly with a large amount. In autumn, pay attention to drainage and waterlogging prevention.
6. Harvesting
From late October to November, when the stems and leaves have all withered, begin harvesting the tubers. Tuber storage is mainly for heat preservation and freeze prevention, with a suitable temperature of 2-4°C and relative humidity of 80-85%. They can be stored in piles, buried, or stored in cellars, etc. In the warm southern China and the Yangtze River basin, they can be marketed as soon as they are harvested. Bulbils must be harvested when mature.