Key Management Techniques for Summer Soybean in the Mid-to-Late Growth Stage

Compared with corn and cotton, soybean requires less labor, less investment and lower cost during its growth period, which is a major advantage of the summer soybean crop, but for soybean to achieve high yield, mid-to-late stage management is the key.

During the flowering and pod-setting stage, vegetative growth and reproductive growth proceed together, and this is the key period that determines the number of pods per plant. After soybean flowering, growth enters a vigorous period, and vegetative growth gradually reaches its peak; the nitrogen-fixing ability of root nodules also gradually increases from the early flowering stage and reaches or approaches its peak at the pod-setting stage. The amount of nitrogen fixed during this period supplies the aboveground parts of the soybean. The flowering and pod-setting stage is the period when soybean needs the most fertilizer and water in its entire life. Sufficient fertilizer and water, strong light and adequate carbon dioxide help promote soybean flowering and pod setting.

The level of soybean yield depends on the number of pods and seeds, so in production management it is required that soybean plants have lush leaves, deep roots and strong stems, so as to achieve many pods and many seeds and obtain high yield.

Drought during the flowering and pod stage has a great impact on the number of pods and seeds of soybean, so irrigation must be carried out in time, and drainage should also be noted on rainy days. At the same time, protection measures should be determined according to the plant's growth vigor and appearance. For those growing excessively and showing spindling, deep intertillage or spraying a growth retardant can be used to control excessive growth. If the plants are weaker, fertilizer should be applied in combination with intertillage and watering, preferably a compound fertilizer, 5-10 kg per mu.

In July-August, soybean is easily harmed by pests, so it is necessary to observe frequently whether there is pest damage and to control it in time. The bridge caterpillar and the soybean worm are common and destructive pests, and they cause more serious damage from late July to early August. Pyrethroid pesticides can be used to control the bridge caterpillar and the soybean worm. The soybean stem black fly and the soybean stem fly are also two soybean pests worthy of attention, and phoxim or pyrethroid pesticides can also be used for control.

In the grain maturation stage, vegetative growth stops, reproductive growth is vigorous, and nitrogen-fixing ability declines rapidly. This period lasts about 20 days. Its early stage determines the number of seeds per pod, and its middle and late stages determine seed weight. During the middle period, the seed-filling rate is relatively fast.

The main goals in the grain maturation stage are to protect leaves, protect roots and increase the number of pods and seeds. The seed-filling stage, especially the early stage, is sensitive to water, and at this time it gradually enters the dry season, so watering is needed when drought occurs. For some plots, foliar fertilization is also needed, spraying 1%-2% urea or 2%-3% superphosphate solution, and the time should be after 3 p.m.

The main pests in the grain maturation stage are the soybean pod borer and the cotton bollworm, which can be controlled with insecticides such as phoxim and deltamethrin.