The demand for sweet potato for nitrogen, phosphorus and potassium varies with the growth period. Nitrogen fertilizer absorbed more during the growth period of stems and leaves, and absorbed less during the period of root enlargement; phosphate fertilizer absorbed less in the middle growth stage of stems and leaves, and absorbed more during the period of root enlargement; and the absorption of potassium fertilizer was more than nitrogen and phosphorus from planting to harvesting. The period of enlargement of the roots is more significant. Therefore, sweet potato fertilization should be carried out around this feature. 1. The base fertilizer for the base fertilizer should be based on farmyard manure, supplemented by chemical fertilizers, and the farmyard manure should be fully decomposed. The amount of base fertilizer generally accounts for 60% to 80% of the total fertilization amount. In general, 667 square meters of fresh potatoes 2500 ~ 4000 kg should be applied to the base fertilizer 3000 ~ 4000 kg. And with the application of superphosphate 15 ~ 25 kg, plant ash 100 ~ 150 kg, ammonium bicarbonate 6 ~ 10 kg and so on. The base fertilizer should be applied in a concentrated and layered manner, 60% applied to the bottom layer during deep tillage, and 40% can be applied at the time of planting. The quick-acting fertilizer applied with the base fertilizer should be applied with the soil and fertilizer, so that the potato seedling can be absorbed after it is alive.   2, look at the seedlings and fertilizers to the sweet potato topdressing period, types, quantities and methods, according to the different growth stages of the appearance and needs to determine. Specifically, it is necessary to catch up with the "five fertilizers." The seedling fertilizer is generally applied to the quick-acting fertilizer. It is combined with the seedlings and seedlings after 3 to 5 days of planting. The method is to open a hole of about 10 cm near the root of the potato seedling, and apply a small amount of urea. 1.5 to 3.5 kilograms per 667 square meters, watering the soil immediately after application, can also be rooted with 1% urea water to supplement the lack of quick-acting fertilizer and slow fertilizer efficiency. After the strong mango sweet potato enters the strong vine stage, the growth potential of the underground part turns to be strong, the roots begin to form, and the absorption power is strong. In order to accelerate the expansion of the leaf area and improve the photosynthetic production efficiency, the sweet potato fertilizer should be applied 30 to 40 days after the sweet potato planting. . The amount of fertilizer applied is determined by the soil fertility and seedling potential, and the application of long-term potential difference is 667 square meters of ammonium sulfate 7.5-10 kg or urea 3.5-4.5 kg or ammonium nitrate 4.5-6 kg, potassium sulfate 10 kg or grass ash 100 kg. If the growth is better, the dosage can be reduced. In combination with fertilization, we must do a good job in weeding, weeding, irrigation and drought prevention. Promote potato fertilizer to promote potato fertilizer to potassium fertilizer, generally 90 to 100 days after planting. Potassium application during the potato period can effectively extend the functional period of the leaves, enhance the vitality of the stems and leaves, increase the photosynthetic efficiency, promote the operation of photosynthetic products, and promote the expansion of potato chips. Generally, 10 kg per 667 square meters of potassium sulfate or 100 to 150 kg of ash can be used. After the application, watering should be carried out once to promote its effectiveness as soon as possible. The sweet potato with cracking fertilizer has obvious premature aging tendency during the expansion period, and the cracking fertilizer has a significant effect of increasing yield. The cracking fertilizer generally uses 4-6 kg of ammonium sulfate per 667 square meters, 400-600 kg of water, or decomposed human feces. 250 kg of urine, 750 kg of water, applied along the crack. During the mid-expansion of the foliar potato block, the root-fat function begins to decline. At this time, the fertilizer should be supplemented by the root-following method, generally using 2% to 5% of the superphosphate leaching solution or 1% of the potassium phosphate solution or 0.3%. The potassium dihydrogen phosphate solution or 5% to 10% of the ash ash filtrate is sprayed after 3 pm, sprayed 75 kg per 667 square meters, sprayed once every 15 days, and sprayed twice. Note: One of the sweet potatoes is a chlorine-free crop. When using fertilizer, pay attention to the fertilizer without chlorine. The ammonium dihydrogenate should not be applied or applied, and it can be made into deep-mixed fertilizer particles. It should be fully decomposed; its four plant ash can not be mixed with nitrogen and phosphorus fertilizers, and should be applied separately. Sports Towel,High Quality Towel Robe,Quick Dry Sport Towel Robe,Sport Towel Supplier Suzhou Golden Gamrnet MFG Co.,Ltd , https://www.suzhoumfg.com