Its life goes through processes such as seed germination, emergence, seedling growth, branching, flowering, pod formation, grain drumming, and maturity. It can be divided into 6 reproductive periods.

(1) Seed germination and emergence period

The radicle first extends from the micropyle of the ovule. When the radicle elongates to the same length as the seed, it is called germination. The hypocotyl elongates, the seed coat falls off, and the cotyledons are exposed to the soil surface as the hypocotyl elongates. When the cotyledons expand, it is called emergence. Under suitable conditions, soybeans can emerge 4-6 days after sowing. The emergence stage is when more than half of the cotyledons are unearthed in the field.

(2) Seedling stage

The seedling stage is from the emergence of seedlings to the differentiation of flower buds. After emergence, the two cotyledons unfold, and the young stem continues to elongate, and the two opposite single leaves on the top unfold immediately. This is called the single-leaf stage. As the young stem continues to elongate, it is called the 3-leaf stage when the first compound leaf grows. At the 3-leaf stage, the above-ground part grows slowly, and the underground roots grow quickly to form root nodules. At the end of this period, the root system is initially formed and begins to require more water and nutrients. The seedling stage is about 20-25 days, accounting for 1/5 of the entire growth period. This period is the rooting stage; attention should be paid to squatting the seedlings and strengthening field management to achieve complete, uniform and strong seedlings, laying the foundation for high yields.

(3) Flower bud differentiation period

The period from the beginning of flower bud differentiation to the beginning of flowering is the flower bud differentiation period, which is also the branching stage. It usually takes about 25-30 days. When 4-5 compound leaves appear, the lower part of the main stem begins to branch and flower buds differentiate. The differentiation and budding of human bean flower buds are carried out under short-term illumination conditions. The process of flower bud differentiation is as follows: first the hemispherical flower bud primitive appears, then forms a blade in front of it, and then forms a tube; then differentiates into keel petals, wing petals and flag petals; the ring-shaped stamen primitives differentiate one after another, and in the stamens The central pistil begins to differentiate, and the ovule primitive body appears; then the ovule and anther primitive body differentiate, and the floral organs gradually grow up, and finally form flower buds, pollen and embryo sacs to complete flower bud differentiation. Flower buds begin to differentiate, and the plant enters a period of simultaneous reproductive growth and vegetative growth. At this time, fertilizer and water management must be strengthened, and attention must be paid to coordinating vegetative growth and reproductive growth to achieve the requirements of strong plants, many branches, many flower buds, and healthy flowers.

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