Causes of Soybean Flower Drop and Its Control Techniques

There are many reasons for soybean falling flowers and pods, mainly as follows:

Under the condition of poor ventilation and light transmission, soybean is easy to lead to falling flowers and pods. Planting soybean due to improper use of varieties, early ridge closure, but also due to excessive density, branches and leaves shielding each other, coupled with high humidity, poor light, low chlorophyll content in leaves, soybean plants gradually turn yellow. Less nutrition accumulation, resulting in flower and pod shedding.

The stage of falling flowers and pods of soybean due to nutrient imbalance is the period with the highest need of nutrients, if the supply of nutrients is insufficient, it will cause flowers and pods to fall off. The fertilizer requirement law of soybean is generally 20% of the total fertilizer from emergence to flowering and 55% from flowering to bulging. 25% from bulging to maturity. According to the law of fertilizer demand, only reasonable fertilization is helpful to the normal production and development of soybean. In the process of fertilization, the combined application of agricultural fertilizer, chemical fertilizer and micro-fertilizer should be achieved: soybean needs more nitrogen fertilizer, followed by phosphate fertilizer and less potassium fertilizer. In the application, it is necessary to combine nitrogen and phosphorus, promote potassium with phosphorus and use potassium to prevent lodging. The combination of base fertilizer, seed fertilizer and topdressing fertilizer, and the combination of flower fertilizer, pod fertilizer and grain fertilizer can fully meet the needs of nutrient elements in different growth stages of soybean and prevent falling flowers and pods.

Insufficient water can not only accelerate the running speed of nutrients and regulate the temperature of plants, but also directly participate in the metabolism of soybean growth and development, so suitable water is conducive to the normal growth and development of soybean. In the flowering and podding stage of soybean, if it is overcast and rainy and the soil moisture is too much, it will not only reduce the sunshine hours, but also decrease the ground temperature, increase the relative humidity, make the plant grow excessively, affect the synthesis and transport of organic matter, and make the flowers and pods fall off; if there is too little water, because the plant does not get enough water, it will wither, in short, it will inevitably lead to flower and pod drop.

Some of the diseases and insect pests directly harm the organs of flowers and pods and cause shedding, while others destroy the plants, affect the growth and cause the shedding of flowers and pods. However, storms and a sudden drop in temperature can also cause flowers and pods to fall off.

Artificial flower and pod shedding in the later stage of improper field management may make soybean stem break, branches and leaves fall off, resulting in artificial flower and pod shedding.

So, how can we prevent falling flowers and pods? To sum up, there are some technical measures as follows:

Reasonable close planting should be reasonably close planted according to the characteristics of varieties and the level of soil fertility, and the requirement for soil fertility is that the fertile land should be thinner and denser. Soybean varieties popularized in Heilongjiang Province should sow about 450000 seeds per hectare under the condition of small ridge narrow row close planting, while large ridge or small ridge narrow row dense planting plot should sow 400000 seeds per hectare.

As scientific topdressing is a crop that needs more nitrogen in beans, it is usually necessary to apply nitrogen fertilizer at one time in the early flowering stage of soybean, which can reduce the shedding rate of flowers and pods and prolong plant life. Generally, ammonium nitrate can be applied 150 kg to 180 kg per hectare, or urea 130 kg. If the extra-root topdressing is carried out at the flowering and pod stage, urea 0.5 kg per mu, calcium superphosphate 1.5 kg, potassium sulfate 0.3 kg, boron nitrate 30 g per mu, or adding appropriate amount of plant nutrition to regulate fertilizer, such as strong roots, 50 kg water, sprayed on the leaf surface, can protect flowers and pods and increase the weight of 100 seeds.

Chemical control treatment can reduce the consumption of nutrients and water and optimize the growth environment, which can promote good growth and prevent flowers and pods from falling.

Drought-resistant and waterlogging-resistant soybean is the period from flowering to podding to absorb the most water in its life. in this period, drought irrigation and waterlogging drainage can reduce the shedding of flowers and pods.

In the land with large continuous cropping area and serious harm, the prevention and control of diseases and insect pests must be carried out in time to reduce the shedding of flowers and pods. At the same time, the management of yield schedule in soybean field should be strengthened to promote good fertility and prevent falling flowers and pods.

In short, as long as planting soybean according to the causes of falling flowers and pods, timely prevention, early detection, and take corresponding technical measures to control, we can ensure high and stable yield and high quality of soybean and achieve considerable economic benefits.