How to apply fertilizer with formula for sweet potato

According to the production practice, the effect of formula fertilization on increasing yield of sweet potato is obvious. The specific measures are as follows: first, topdressing method 1. Base fertilizer: the ratio of nitrogen, phosphorus and potassium is generally 1 ∶ 1.5 ∶ 3. In the middle-yield potato field with a yield of 2500 to 3000 kg per mu, about 7.5 kg of pure nitrogen, 7.5 kg of phosphorus and 15 kg of potassium were applied per mu. Base fertilizer should account for 7080% of the total amount of fertilizer. Generally speaking, base fertilizer applies 1500kg to 2000kg of slag fertilizer per mu, 2.5kg to 5kg of urea (or 7.5kg to 12kg of ammonium bicarbonate), 10kg to 15kg of phosphate fertilizer, 50kg to 75kg of plant ash (or 7.5kg to 10kg of potassium chloride). The application of base fertilizer should adopt the layered application method of crude fertilizer and shallow application of fine fertilizer. That is, before planting seedlings after ridging, open ditches or dig holes according to rows and holes, apply the base fertilizer into the ditches or holes, and then use hoes to mix the soil fertilizer. The centralized fertilization method of box fertilizer can also be used, that is, fertilizing in the box, ploughing the box, and wrapping the fertilizer in the box. By adopting these centralized fertilization methods, the loss of fertilizer can be reduced and the purpose of economic fertilizer use can be achieved. 2. Topdressing: topdressing should be divided into 3 times. For the first time, about 10 days after planting, intercropping was applied early through the forest 20-30 days before corn harvest, accounting for 2025% of the total topdressing fertilizer, 500kg 750 kg of human and animal feces per mu or 1.5 kg 2.5 kg of urea per mu, and applied to water holes. Seedling fertilizer should be applied appropriately according to the amount of base fertilizer, weather and seedling growth, so as to prevent excessive application from causing seedling growth. The method of applying more weak seedlings and less prosperous seedlings can also be adopted to promote the balanced growth of the whole field. For the second time, about 60 days after planting, the stems and leaves grew vigorously, and the tubers gradually expanded and needed more fertilizer. Those who grow well and have applied seedling fertilizer are mainly potash fertilizer, while those with poor growth are suitable to apply more nitrogen fertilizer, combined with potash fertilizer. Generally, 1000 kg of human feces and urine, 100kg of plant ash, 10kg of urea, 10kg of calcium superphosphate and 7.5kg of potassium chloride were applied to water holes, combined with management measures such as ploughing, weeding and soil cultivation. The third time was carried out 80 days after planting, 2.5 kg urea per mu, and 75 kg 100 kg soaked in 2% calcium superphosphate or 5% plant ash 30-50 days before harvest, sprayed once every 10-15 days, a total of 2-3 times, 1% urea solution could be sprayed on stems and leaves with poor growth. The suitable spraying time is 4 ~ 5 o'clock in the afternoon on a sunny day. Second, fertilizing autumn potato, autumn potato is planted before and after "the Beginning of Autumn", and the growth period is about 100days. Therefore, we must grasp the characteristics of short growth period and concentrated fertilizer demand of autumn potato, and adopt corresponding fertilization techniques. The principles of applying sufficient base fertilizer, early application of seedling fertilizer and re-application of strong rattan fertilizer should be grasped in the fertilization of autumn potato. General base fertilizer per mu 500,750 kg of barnyard manure, 2.5 kg of urea, 10 kg of phosphate fertilizer, 50 kg of plant ash or 5 kg of potassium chloride, strip or hole application. About 10 days after planting, the seedling fertilizer was applied, 750 kg of clear water manure or 2.5 kg of urea was applied per mu, and water hole was applied. About 40 days after planting, Zhuang rattan tuber fertilizer was applied. This time, the fertilizer could be applied with 750-1000 kg of mature human and animal manure mixed with 50 kg of plant ash, combined with mid-ploughing and soil cultivation to prevent nutrient loss. 3. The principles of potato tip overwintering fertilization are as follows: early re-application of base fertilizer, proper application of fixed seedling fertilizer, overwintering fertilizer of seedlings, and frequent application of spring fertilizer. Base fertilizer is the basis for the growth of potato seedlings. The application should be mainly based on mature high-quality pile manure, and the amount of fertilizer should be 100kg to 150kg per bed (6.6 square meters). It should be applied about 10 days before planting and be fully mixed with the soil. After planting potato seedlings, according to the dry and wet bed soil, 100-150 kg of rotten human and animal fecal water should be applied to combine soil and seedlings, stabilize seedlings and promote roots. Potato seedlings do not need much fertilizer during the overwintering period. in the case of applying sufficient base fertilizer and seedling fertilizer, there is no need to topdressing. However, if it is found that the leaves are thin and small, the leaves are yellow and lack of fertilizer, some fine compost and plant ash can be applied in the sunny afternoon, which not only has fertilizer effect, but also can absorb moisture, heat and heat. Extra-root topdressing can also be carried out and sprayed with 2% superphosphate or 20% plant ash extract to increase the sugar content in the seedling and enhance the cold resistance. After the beginning of spring, the young buds of potato seedlings begin to sprout, and the soil should be loosened and fertilized in time. Topdressing should first be light and then thick, first less and then more, first mature pig manure water and then mature human urine water and chemical fertilizer. The chemical fertilizer is sprinkled on the water and wash the seedlings with clean water to avoid burns. Head fertilizer, 100 kg of rotten pig manure can be applied to each bed, and then manure will be applied every 7 to 10 days according to the growth of potato seedlings. After cutting the seedlings, fertilizer should be applied every time to promote the rapid development of the seedlings.