Sweet potatoes are a dual-purpose crop used for both food and vegetables . Fertilization management is a crucial aspect in producing high-quality and high-yield sweet potatoes. Scientific fertilization based on the nutrient requirements of sweet potatoes can not only meet their nutrient needs during their growth period but also achieve cost savings and increased efficiency.
1. Apply base fertilizer properly.
When preparing the land and making ridges, apply 3,000-4,000 kg of well-rotted farmyard manure per acre, along with 15-30 kg of phosphorus and potassium fertilizer.
2. Vine Fertilizer
After sweet potatoes enter the vigorous vine stage, the underground parts grow rapidly, tubers gradually form, and the ability to absorb fertilizer is strong. 30-40 days after planting, we need to apply a fertilizer to promote vigorous vine growth. The specific amount of fertilizer should be determined based on soil fertility and seedling vigor. For plants with poor growth, more fertilizer can be applied, such as 8-10 kg of ammonium sulfate and 10-15 kg of potassium sulfate per acre. For fields with good growth, the amount should be halved.
3. Potato-promoting fertilizer
To achieve high yields of sweet potatoes, it is essential to apply fertilizer that promotes tuber growth, primarily potassium fertilizer. Applying potassium fertilizer 90-100 days after transplanting during the tuber-promoting period effectively prolongs the functional period of leaves, enhances stem and leaf vitality, improves photosynthesis, and promotes rapid tuber enlargement. Potassium sulfate is generally recommended, at a rate of 10-15 kg per acre. Watering is necessary after fertilization to maximize fertilizer effectiveness.
4. Foliar fertilizer
During the mid-stage of tuber enlargement, the plant's root system begins to absorb nutrients less efficiently. At this time, foliar fertilization can be considered to supplement the fertilizer supply . Generally, a 1% potassium phosphate solution or a 0.3% potassium dihydrogen phosphate solution can be sprayed after 3 PM, once every 10-15 days, for a total of 2-3 applications.
5. Precautions for fertilizing sweet potatoes
When fertilizing sweet potatoes, avoid using fertilizers containing chlorine. Regarding nitrogen fertilizer, if using ammonium bicarbonate, it should not be broadcast. If using wood ash, it should not be mixed with nitrogen or phosphorus fertilizers; it is best to apply them separately.
