During which stage does soybean typically experience the greatest yield reduction due to drought stress?

The pod development stage is typically when soybean plants experience the most significant yield reduction due to drought stress. This critical phase occurs just after flowering and is essential for filling the developing seeds within the pods. At this time, the plants require a substantial amount of moisture to ensure that the pods can properly develop and fill with seeds. Insufficient water during this stage can lead to poor seed formation, reduced pod size, and ultimately lower seed weight, which directly impacts overall yield.

While drought stress can affect soybeans at any growth stage, its impact is particularly detrimental during pod development because the plant is investing energy in seed growth and maturation. The critical processes involved in pod filling and seed development are highly sensitive to water availability. Without adequate moisture, the plant cannot sustain the resources needed for these processes, resulting in significant yield losses.

In contrast, earlier stages such as seedling emergence or early vegetative growth are less sensitive to drought in terms of yield, as they are primarily focused on establishing the plant rather than producing seeds. While drought can still impact these stages, the effects are not as pronounced in terms of yield loss compared to what is experienced during pod development.