1, Chinese yam is a shallow-rooted crop, with a long growth period and one crop a year. It is usually planted when the ground temperature reaches10 C in spring. For planting yam, it is necessary to choose Gao Qian, which has good drainage, deep soil layer and soft sandy loam or light loam fields. The soil quality is required to be the same from top to bottom, and the soil should be slightly acidic to neutral. Yam should not be used for continuous planting. Usually, it should be rotated every 2 to 3 years.
2. When digging cultivation ditches, the ditch spacing is about 1 m, the depth is 0.6~ 1.0 m, and the width is 25 cm. When digging ditches, the topsoil and subsoil are stacked separately, so that the soil is completely weathered. After the soil is thawed in spring, the lower soil is first buried in the ditch, and then the top soil is filled to prevent the soil layer from being disordered. Combined with the fill, apply 1000- 1500kg soil miscellaneous fertilizer 50kg-70kg phosphate fertilizer, 25kg-30kg ammonium bicarbonate and 25kg-30kg potassium sulfate to it. Avoid using a large number of organic fertilizers that have not been decomposed, so as to prevent burning roots and branching of tubers.
Second, seed block treatment
20-25 days before planting, select the root head with hard top of the disease-free block that conforms to the characteristics of the planted variety as the seed, dip one end section of the root head in slaked lime powder, and then expose it to sunlight for several days to disinfect and promote germination. In order to increase the propagation coefficient, the root head must be cut off for propagation. That is to say, thin roots with a length of about 1 m and a transverse diameter of 2.4-4.5 cm are selected, cut into sections with a length of 15-20 cm, and the upper and lower ends are marked with wool, then each section is dipped in lime, and the seeds are exposed to the sun horizontally until there are fine cracks at the ends of the sections. Gently handle the seeds during drying to prevent scratches. At the same time, we should do a good job in wind, rain and frost protection.
Third, yam planting
After the yam cultivation ditch was filled with soil fertilizer, the ditch was made into a flat bed with a width of about 1 meter. When planting, plant and dig a ditch about 10 cm deep in the middle of the flat border, and then water it. When water permeates, the yam is planted in the ditch according to the plant spacing of15-20cm, and about 4,000 plants are planted per mu. Cover the soil with 8~ 10 cm, and then cover with film to increase the soil temperature and promote the emergence of seedlings. When yam bean is used to breed Chinese yam seeds, the propagation coefficient is increased, the row spacing is 40-50 cm, and the plant spacing is about 10 cm. Plant about 12,000 plants per mu.
Fourth, post-planting management
The stems and leaves of Dioscorea opposita like high temperature and dry environment, and are not resistant to frost. The average root temperature of roots began to germinate above 10℃, and the suitable germination temperature was about 25℃. The growth of stems and leaves is the best at 25 C-28 C, and the tuber growth is the fastest at 20 C-24 C. After yam cultivation, it takes 35 days to emerge.
1, scaffolding to lead vines: the stems of yam are thick and tender, and the vines should be supported in time after emergence. According to the characteristics of the right-handed stem of Chinese yam, the tendril spirals and rises, and the height is about 1 m. If there are too many lateral branches at the base of the main vine, they can also be removed appropriately to facilitate ventilation and light transmission. When a large amount of "yam bean" is formed between leaves, it can also be removed early to save nutrition.
2, intertillage and soil cultivation: Ying Qin intertillage and weed control in the early growth stage, usually every half a month, until the stems and vines have been put on half a shelf, and then weeds are pulled out. It is necessary to dig up a part of the soil between rows outside the frame and fill it in the rows inside the frame, so that a high ridge can be formed inside the frame, and a grooved frame with a depth of 20cm and a width of 30cm can be formed between the outer rows to facilitate drainage in rainy season.
3. Rational topdressing: When the stem is already in the upper part of the shelf, topdressing 1 time, generally applying 25~35 kg of high-concentration compound fertilizer per mu. Or ditching from 20 to 30 cm of plants, applying 500~ 1000 kg of organic fertilizer, watering after fertilization, applying 10 kg/mu of urea when the stems and vines are full, and spraying O.3％% potassium dihydrogen phosphate solution on the roots for 2-3 times in the late growth stage in combination with disease prevention and control.
4. Combination of irrigation and drainage: Yam is a drought-tolerant crop, but it should be properly watered for high yield. Generally speaking, before and after the first topdressing, if the soil turns completely white after a long drought, water should be lightly poured 1-2 times to wet the soil surface. In the future, at the turning point of summer and autumn, if the weather is hot and dry over 1 week, cold water must be poured in the morning to resist the drought. Yam is more afraid of waterlogging, so it is necessary to clean ditches in the rainy season to achieve no water in the field.