Sweet potato

1. Nutritional characteristics

The growth period of sweet potato can be divided into root branching period (planting to ridge sealing, mainly root growth), stem and leaf growth and tuber expansion period (ridge sealing to peak growth of stem and leaf, potato vine and long, mainly stem and leaf growth), root growth and stem and leaf decline period (peak growth of stem and leaf to harvest, mainly root growth).

2, need fertilizer characteristics

In the whole growth period of sweet potato, the amount and proportion of nitrogen, phosphorus and potassium are different due to different factors such as soil, climate, varieties and planting methods. The yield of fresh potato 3000 ~ 4000 kg per mu requires nitrogen (N) 12 ~ 16 kg, phosphorus (P2O5) 6 ~ 9 kg, potassium (K2O) 15 ~ 20 kg.

Sweet potato is a potassium-loving crop, with the largest demand for potassium fertilizer, followed by nitrogen fertilizer and less phosphorus fertilizer. The general trend of absorption of nitrogen, phosphorus and potassium is: the absorption is rapid in the early and middle period, and slow in the late period. The nitrogen absorption rate of sweet potato was fast in the early and middle stages of growth, and the nitrogen demand was large, and the nitrogen absorption reached the peak at the peak of stem and leaf growth. The absorption of phosphorus and potassium reached the peak in the expansion stage of potato block, and was higher than that of nitrogen and phosphorus from the beginning of growth to harvest.

Sweet potato calcium, magnesium, zinc, boron requirements are small, but it is also necessary for normal growth, lack of symptoms often cause production reduction. Zinc can increase the length of main and lateral vine, number of leaves per plant and main stem thickness of sweet potato. It can increase the yield of potato chips. Magnesium and boron can increase the content of vitamin C and soluble sugar. (Taken from the network, if there is infringement, please contact to delete.)

3. Fertilization technology

Base fertilizer: It is recommended to apply strong high-nitrogen and high-potassium special formula fertilizer (18-8-16, 14-8-18), applying 60 to 80 kg per mu.

Topdressing: For areas with high yield requirements, apply 5 ~ 8 kg urea, 6 ~ 10 kg potassium sulfate or 15 ~ 20 kg special formula fertilizer with high nitrogen and high potassium in mu at the branching potato stage (30 ~ 60 days after planting for spring potato and 20 ~ 40 days after planting for summer potato).

The spreading should be combined with the ploughing of the cultivated land into the soil or the furrow covering. The furrow application should pay attention to the separation of fertilizer and seed potatoes, and keep at least 8 ~ 10 cm distance to prevent the burning of seeds and seedlings.