Detailed Explanation of Key Points for High-Yield Cultivation Technology of Film-Mulched Sweet Potato
1. Select suitable plots and apply more fertilizer. It is best to choose fertile, level, and irrigable loam soil for planting sweet potatoes. For film-mulched plots, deepen the plow layer. Autumn plowing should be about 25 cm deep. Apply more than 2500 kg of high-quality decomposed farmyard manure per mu. When plowing, broadcast 2/3 of the farm manure and apply 1/3 in furrows when ridging. At the same time, apply 20 kg of potassium sulfate compound fertilizer (N, P2O5, and K2O content each 15%) and 10 kg of potassium sulfate per mu.
2. Ridging specifications and film-mulching technology. Around May 1, form ridges with a ridge spacing of 50 cm. Level the ridge surface to prevent clods from breaking the film. It is best to cover the film after rain. If there are weeds, use 0.1 kg of 50% acetochlor emulsifiable concentrate herbicide per mu, mix with 70 kg of water, and spray evenly. After spraying thoroughly, cover the film immediately. The film width is 120 cm. Cover two ridges at a time, using 6 kg of film per mu. When covering the film, pull it tight and cover and firm the soil thoroughly. On the film, press a soil band horizontally every 2 meters, then wait to plant seedlings.
3. Planting seedlings: For film-mulched cultivation, the sweet potato variety should be the relatively popular 868 series on the market, such as Yiwofeng. After raising seedlings, generally plant seedlings from May 8-15. On the premise of ensuring no cold damage, the earlier the planting period, the better. Choose clear and windless weather. On ridges with 50 cm row spacing, plant at 30 cm plant spacing. Use a 3.3 cm diameter hole puncher to punch holes manually. Generally, the planting depth of vines is about 6 cm, and keep 4200 seedlings per mu. After planting, leave 3 leaves on the aboveground part of the seedlings, with about 3 cm exposed. First water the holes fully, plant the seedlings immediately, and after the water seeps down, seal the holes tightly. If it is too dry, irrigate along the furrows after planting.
4. Field management: Film-mulched sweet potatoes have a good waterlogging prevention effect. In case of special drought, irrigate along the ridges under the film. When there is a lot of rain, drain water in time. During the entire growth period of sweet potatoes, turning the vines is strictly prohibited. Generally, no topdressing is needed, and pests and diseases rarely occur. In the middle growth stage, according to the plant growth appearance, spray 50 kg of 0.2% potassium dihydrogen phosphate solution per mu. It is best to spray fertilizer in the evening, once every 6-7 days, for 3-4 consecutive times.
5. Harvest: Film-mulched sweet potatoes are generally harvested around October 1 and brought to market immediately after harvest.