The soybean plant experiences two main growing cycles: the vegetative stages, which include emergence, the unfolding of the unifoliolate leaves and a series of appearance of trifoliolate leaves; and the reproductive states, which include flowering, the appearance of pods, increasing levels of seed growth, and full color maturation. Specific details of each growing stage depend on the variety of soybean plant cultivated.
During the emergence stage, the germinating seed of a soybean plant presents cotyledons or embryonic leaves. These leaves are a precursor to the unfolding of unifoliolate leaves, which are compound leaves that grow at the end of a stem. After this stage, a series of trifoliolate leaves emerge from subsequent stems.
With the vegetative stages complete, the soybean plant begins the process toward reproductive maturation. Initial flowering occurs when one flower appears on one node. Full flowering occurs when there are open flowers on any node. Pods then form on the uppermost nodes of the plant, reaching full potential when pods are 3/4-inch on each of the four uppermost nodes.
The stage of beginning seed occurs when 1/8-inch seeds begin to grow in the pod. When the seeds fill the capacity of the pod and at least 95 percent of the pods attain a mature color, the soybean plant has completed its cycle.