Early Soybean Development

  • Jun 06
    Laura Johnston
    Early Soybean Development By Laura Johnston on June 6, 2014
    Categories: Soybean

    When soybeans are planted, germination begins by the seed absorbing water from the soil until the moisture content is approximately 50%. The radicle is the first visible sign of germination and grows downward (primary root). Not long after the radicle emerges, the hypocotyl starts growing upwards pulling the cotyledons. After it emerges, the hook shaped hypocotyl straightens out and the cotyledons open to allow the growing point to become exposed to the sun. Emergence usually occurs 5 to 21 days after planting, depending on soil moisture, soil temperature, and planting depth. Soybeans planted in the last 10 days have been emerging in 5-8 days due to the warm, moist soil conditions.

    When we describe soybean development, the stages are split up into vegetative and reproductive development. The first two leaves on a soybean plant are called unifoliates and are opposite to each other and above the cotyledons. Leaves that emerge after are trifoliates (three leaflets) and alternate on either side of the stem. Once a plant has 2 to 3 trifoliates, nodules begin to appear on the roots and start fixing atmospheric nitrogen.

    Longer season varieties that are planted late reach maturity faster than those planted early due to the soybean becoming more influenced by day length.

    It is always a good idea to monitor emergence, especially if your soils are prone to crusting. Being proactive can prevent a replant situation.

    If you have any questions or concerns, please contact your Maizex representative.

    Laura Johnston, CCA-ON, Maizex Seeds Yield Specialist, West Elgin County
    Twitter: @lmjohnston8