How to topdressing soybeans more effectively

According to the law of fertilizer requirement of soybean, the period from flower bud differentiation to initial flowering stage is the period of both vegetative growth and reproductive growth, and it is also the period when soybean plants need a lot of nutrition. Under the condition of high yield cultivation, only relying on soil fertility and applied base fertilizer and seed fertilizer can not meet the requirements.

There is an obvious effect of increasing yield by topdressing soybean from branching stage to early flowering stage. Especially in the land with low soil fertility and weak growth in the early stage of soybean, the effect of topdressing at the root is more significant. Applying 75 kg of urea and 37.5 kg of potassium sulfate per hectare at flowering stage can increase soybean yield by 21.9%. However, in the case of more fertile soil, or more base fertilizer and seed fertilizer, soybean plants grow healthily, and when they are more luxuriant, it is not suitable for root topdressing, let alone nitrogen fertilizer, otherwise, it will cause overgrowth and lodging and reduce yield.

Available fertilizers can be used as topdressing, such as urea, ammonium nitrate, potassium sulfate, potassium chloride and so on. The root topdressing of soybean at the early flowering stage is mainly nitrogen fertilizer, and can be properly mixed with phosphate fertilizer and potash fertilizer. Generally, urea 37.5kg / ha or ammonium sulfate 150kg / ha, potassium chloride or potassium sulfate 75kg / ha and calcium superphosphate 112.5kg / ha can be applied.

Topdressing is generally combined with ploughing and weeding. After weeding, ditches are opened on the ridge side (5 cm from the plant) with a depth of 5 cm to 10 cm. The fertilizer is evenly applied to the ditch, and the soil is covered immediately after application to prevent the loss of nitrogen volatilization. We should pay attention to the rotation of drugs and promote the use of high-efficiency and low-toxic biological pesticides.