What to expect when you are expecting… seedling emergence.

May 3, 2022 8:30 AM
Blog Post

Over the last couple of weeks there have been numerous reports of both corn and soybean fields being planted. At present, soil temperatures are hovering just below 50oF for most of the state, with the exception of portions of southern corner of Iowa. What should we expect from these early planted fields?

There could definitely be some imbibitional chilling or cold injury. Anticipate emergence to take longer than normal because of the colder soil temperatures. Be aware that delayed emergence puts the seedling at higher risk of disease pathogen infection and insect feeding. And because of these side affects you might also expect uneven and low stand establishment.

At this point, there is nothing that can be done for corn and soybean that have already been planted. If you are curious of the impact that this temperature change made, conduct stand assessments once corn and soybean emergence occurs. There are 3 easy steps;

  1. Determine what the plant population is. Simply count the number of plants emerged in 1/1000th of an acre (17’5” for 30-inch rows). Knowing your plant population can give you an early indication of yield potential.
  2. Identify emergence uniformity. Look to see if all plants evenly spaced within the row. Pay attention to how uniform plant height is to determine how uniform the emergence rate was.
  3. Evaluate why plants are missing or delayed. Dig along the furrow to find the presence of a seed. If there is no seed, it is likely a planter performance issue. Plants that emerge days later may be the result of deeper seed depth placement or reduced seedling vigor.

Mark Licht Associate Professor

Dr. Mark Licht is an associate professor and extension cropping systems specialist with Iowa State University Extension and Outreach. His extension, research and teaching program is focused on how to holistically manage Iowa cropping systems to achieve productivity, profitability and en...