A Detailed Guide to Yam Planting Methods and Key Technical Points

Yam has the effects of nourishing and strengthening the body, aiding digestion, reducing spontaneous sweating due to deficiency, and stopping diarrhea. It mainly treats spleen deficiency diarrhea, lung deficiency cough, diabetes wasting-thirst, frequent scanty urination, nocturnal emission, leucorrhea in women, and indigestion-related chronic enteritis. Yam is best taken together with reishi mushroom, and has the effect of preventing and treating diabetes. Yam has great development prospects in the food industry and processing industry.

Planting methods

I. Land preparation and trench digging

Yam is a shallow-rooted crop with a long growing period, one crop per year, and is generally planted in the field in spring when the ground temperature reaches 10 degrees Celsius. For yam planting, choose a field of sandy loam or light loam with high and dry terrain, good drainage, deep and loose soil layers, requiring the upper and lower soil textures to be consistent, and the soil is preferably slightly acidic to neutral. Yam is not suitable for continuous cropping, and generally a rotation should be carried out once every 2 to 3 years.

When digging the cultivation trench, the trench spacing is generally about 1 m, the depth is 0.6 to 1.0 m, and the width is 25 cm. When digging the trench, pile the topsoil and the subsoil separately so that the soil is fully weathered. After the soil thaws in spring, first fill the subsoil into the trench, then fill in the topsoil, so as not to disturb the soil layers. Combined with filling the soil, generally apply 1000 to 1500 kg of farmyard manure per mu, 50 kg to 70 kg of phosphate fertilizer, 25 kg to 30 kg of ammonium bicarbonate, and 25 kg to 30 kg of potassium sulfate on top. Avoid applying large amounts of undecomposed organic fertilizer to prevent root burn and tuber branching.

II. Seed piece treatment

20 to 25 days before planting, select a disease-free root head from the harder upper end of the tuber that matches the characteristics of the variety to be planted as the seed, dip one cut end in slaked lime powder, then place it in the sun to dry for a few days to sterilize and promote sprouting. If you want to increase the propagation coefficient, the tuber roots must be cut into pieces for propagation. That is, select relatively thin tuber roots about 1 m long and 2.4 to 4.5 cm in transverse diameter, cut them into several small sections 15 to 20 cm long, and use a brush to mark the upper and lower ends, then dip each cut end in lime, place them horizontally in the sun to dry the seed pieces, and sun them until fine cracks appear at the cut ends. During the seed-drying period, handle them gently to prevent bruising. At the same time, do a good job of wind protection, rain protection, and frost protection.

III. Yam planting

After the yam cultivation trench is filled with soil and fertilizer, make a flat bed about 1 m wide on top of the trench. When planting, open a planting trench about 10 cm deep in the middle of the flat bed, then water. After the water seeps down, lay the yam seed pieces flat in a single row in the trench at a plant spacing of 15 to 20 cm, planting about 4000 plants per mu. Cover with 8 to 10 cm of soil, then add plastic film to preserve moisture, increase soil temperature, and promote emergence. When using "yam beans" to propagate yam seed pieces, two rows can be placed in one bed to increase the propagation coefficient, with a row spacing of 40 to 50 cm and a plant spacing of about 10 cm. Plant about 12000 plants per mu.

IV. Management after planting

The stems and leaves of yam prefer a high-temperature and dry environment and are not tolerant of frost. The tuber roots begin to sprout when the daily average temperature is above 10 degrees Celsius, and the suitable temperature for sprouting is about 25 degrees Celsius. The optimum temperature for stem and leaf growth is 25 degrees Celsius to 28 degrees Celsius, and the fastest tuber enlargement occurs at 20 degrees Celsius to 24 degrees Celsius. After planting, yam takes 35 days to emerge.

1. Trellising and vine guiding: The aboveground stems of yam are slender and tender, so after emergence, supports should be set up in time to train the vines. According to the right-twining characteristic of yam stems, guide the vines to coil and rise, with the trellis about 1 m high. If there are too many lateral branches at the base of the main vine, they can also be appropriately removed to facilitate ventilation and light penetration. When a large number of "yam beans" form in the leaf axils, part of them can also be removed early to save nutrients.

2. Intertillage and hilling: In the early growth stage, frequent intertillage and weeding should be carried out, generally once every half month, until the stems and vines have climbed halfway up the trellis, after which weeds are pulled out. A portion of the soil between the rows outside the trellis should be dug up and filled between the rows inside the trellis, so that a high bed is formed inside the trellis and a trench 20 cm deep and 30 cm wide is formed between the rows outside the trellis, to facilitate drainage in the rainy season.

3. Timely chemical control: Paclobutrazol has a significant inhibitory effect on the aboveground growth of yam, and can also inhibit the formation of bulbils, increasing yam yield by more than 10%. The best time to spray paclobutrazol is when the yam vines have fully covered the trellis and at the early stage of budding and flowering. Use 60 to 70 g of 15% paclobutrazol wettable powder per mu, add 50 kg of water, mix evenly, and spray. For fields with excessive growth, a second spraying can be carried out at an interval of 7 to 10 days.

4. Reasonable topdressing: Apply topdressing once when the stems and vines have climbed halfway up the trellis, generally 25 to 35 kg of high-concentration compound fertilizer per mu. Or apply 500 to 1000 kg of decomposed organic fertilizer in a trench 20 to 30 cm away from the plants. Water after fertilizing. Later, when the stems and vines have fully covered the trellis, if there is yellowing, thinning, and exhaustion, urea can be topdressed again at 10 kg/mu. In the late growth stage, combined with disease and pest control, spray a 0.3% potassium dihydrogen phosphate solution 2 to 3 times on the leaves to protect the leaves and prevent aging.