during the vigorous growth of Chinese onion, fertilizers containing nitrogen and potassium are mainly applied. Nitrogen element can improve the leaves of Chinese onion, and potassium fertilizer can improve the quality of pseudostems. When preparing soil, potassium sulfate fertilizer with high nitrogen and high potassium can be applied to increase the yield of Chinese onion. When harvesting in late September or early October, topdressing can be carried out once, urea can be applied, and water can be poured once after topdressing to dilute fertility and till harvest.

topdressing time of scallion

After beginning of autumn, Bailu and first frost, the best topdressing time of scallion is in late August, early September and early October.

What fertilizer is used for topdressing green onions

Green onions require a lot of nutrients, and generally need to be applied with pure nitrogen, phosphorus pentoxide and potassium oxide. The absorption ratio of nitrogen, phosphorus and potassium is 1∶.4∶1.3, which is very sensitive to potassium and nitrogen nutrition. Therefore, attention should be paid to the use of nitrogen fertilizer and potassium fertilizer in topdressing, and high-nitrogen and high-potassium potassium sulfate fertilizer can be applied in soil preparation to improve the yield of green onions.

topdressing with urea or compound fertilizer for scallion

During the vigorous growth of scallion, fertilizer containing nitrogen and potassium is mainly applied. Nitrogen can improve the leaves of scallion, and potassium can improve the quality of pseudostems, so it is best to use compound fertilizer.

topdressing method for green onions

Before planting green onions, sufficient base fertilizer can be applied, which can be fully decomposed organic fertilizer, and calcium phosphate, plant ash or potassium sulfate can be added to the soil with less phosphorus and potassium. In addition, copper phosphate and boric acid can be sprinkled.

topdressing principle of scallion

The fertilization method of scallion should be based on the principle of "less application and multiple applications", and the topdressing should be divided into 3-4 times from planting to harvesting.

topdressing amount of scallion

If the soil planted with scallion contains low potassium, the amount of potash fertilizer should be appropriately increased, and the amount of topdressing should depend on the target yield. At the high-yield level, such as the yield of more than 1, kg per mu, the amount of potash fertilizer taken away from the soil by scallion every season needs to be replenished in time.

Precautions for topdressing green onions

The principle of topdressing green onions is "light before, medium before, and medium after attacking".

1. After planting, watering and fertilization are not needed at the seedling stage after summer, only shallow intertillage and loosening soil are needed. When the climate turns cool after beginning of autumn, the plant growth will gradually accelerate, and topdressing should be done once, and NPK compound fertilizer or urea, potassium sulfate or decomposed organic fertilizer should be applied.

2. The first ten days of September is the vigorous growth period of scallion, and the scallion enters the peak growth period. At this time, there is a great demand for fertilizer. The second topdressing should be carried out, and the compound fertilizer of nitrogen, phosphorus and potassium should be applied, or the decomposed human excrement and urine should be applied, or ammonium humate and calcium superphosphate should be spread in plant ash. The third topdressing should be carried out in late September or early October, and urea should be applied. After topdressing, water and soil should be cultivated until the harvest.