When a seed germinates, it can generally be extended by 1 main stem, but sometimes it can be extended by more than 2 main stems, resulting in 2-3 tubers, competing for nutrients, making each tuber thin and small, which affects high-quality production. After the emergence of seedlings, the extra stems and vines should be pulled out immediately, leaving only the main stems with a thickness of 1.
Some varieties have too many lateral branches, so the embolism of lower lateral branches and main stem lateral branches should be picked properly in the middle and late stage. The formation of a large number of laiji affects the growth of tubers, which can generally be controlled at 1500-2250 kg/ha.
2. Fertilization: Yam needs a lot of fertilizer. Every 1 0,000 kg tuber needs to absorb about 4.32kg pure nitrogen,10.07 kg phosphorus pentoxide and 5.38kg potassium oxide. Yam is chlorine-free, so potassium chloride should not be used, and organic fertilizer should be applied again.
Generally, 45-75 cubic meters of decomposed organic fertilizer, 350-400 kg of diammonium phosphate, 250-300 kg of urea and 0/50 kg of potassium sulfate/kloc should be applied to the base fertilizer of high-yield fields per hectare. Before soil preparation, it should be spread in the field and turned over in the soil layer of about 25 cm. In the vigorous growth period of stems, leaves and tubers, topdressing is needed 1 time. Apply about 400 kilograms of NPK compound fertilizer per hectare and water it.
3. Irrigation: As long as the topsoil is less than 5 cm wet in the early stage, there is no need to water it. Generally 1 m or so; About 20 days apart, enter the peak growth period of branches and leaves, and then water for the second time. Water should be lightly poured for the first two times, and flooding is strictly prohibited. After the second irrigation 1 month or so, the tuber will expand rapidly. If the soil is dry, it should be watered thoroughly. Pay attention to drainage and flood control in autumn.
Step 4 harvest
From late June of 65438+ 10 to June of 165438+ 10, all stems and leaves withered, and tubers were harvested. Tuber storage is mainly based on heat preservation and antifreeze, and the suitable temperature is 2-4℃ and the relative humidity is 80-85%. Can be stacked, buried or stored. In the warm south and the Yangtze River valley, it can be listed with the harvest, and it must be harvested maturely.
growing environment
It grows on slopes, valleys, forests, streams, roadside bushes or weeds at an altitude of 150- 1500m. Yam is a short-day and warm-loving crop. The optimum temperature for seedling growth is 15-20℃. The optimum growth temperature is 25-28℃, and the growth is slow below 20℃.
It is suitable to grow in loose, fertile and deep soil, while flat species and block species can also grow in shallow and viscous soil. Yam is drought-tolerant, but not waterlogging-tolerant, so it is not suitable for planting in soil with too shallow or too wet groundwater level. The water content of sandy soil and loam is about 65438 08%.