Soybean topdressing timing and methods: do it this way for higher fertilizer efficiency

Judging from the fertilizer requirements of soybeans, the period from flower bud differentiation to early flowering is when vegetative growth and reproductive growth proceed together, and it is also the period when soybean plants need large amounts of nutrients. Under high-yield cultivation conditions, soil fertility plus the base fertilizer and seed fertilizer already applied often cannot meet the requirements.

Applying one topdressing from the branching stage to the early flowering stage of soybeans has an obvious yield-increasing effect. This is especially true for plots with low soil fertility, weak early growth of soybeans, and rows that cannot close over; root topdressing is even more effective there. During the flowering stage of soybeans, applying 75 kg of urea and 37.5 kg of potassium sulfate per hectare can increase soybean yield by 21.9%. However, when the soil is relatively fertile, or when large amounts of base fertilizer and seed fertilizer have been applied, and the soybean plants are robust and relatively luxuriant, root topdressing should not be carried out, and nitrogen fertilizer topdressing is even less suitable; otherwise, it will cause excessive vegetative growth and lodging, reducing yield.

Quick-acting fertilizers can be used for topdressing, for example: urea, ammonium nitrate, potassium sulfate, potassium chloride, etc. For root topdressing at the early flowering stage of soybeans, nitrogen fertilizer is the main type, and phosphate fertilizer and potassium fertilizer can also be appropriately combined. Generally, 37.5-75 kg of urea or 150 kg of ammonium sulfate can be topdressed per hectare, 75-150 kg of potassium chloride or potassium sulfate can be topdressed, and 112.5-150 kg of superphosphate can be topdressed.

Topdressing is generally carried out together with intertillage and weeding. After weeding, open a furrow on the side of the ridge (5-10 cm from the plants), with a furrow depth of 5-10 cm, apply the fertilizer evenly in a band in the furrow, and immediately cover with soil by hoeing after application to prevent nitrogen volatilization loss. Pay attention to rotating pesticides, and advocate the use of high-efficiency, low-toxicity biological pesticides.