Soybean Planting Populations and Seed Treatments - U of I Extension

News Release

Soybean Planting Populations and Seed Treatments

This article was originally published on August 17, 2018 and expired on October 21, 2018. It is provided here for archival purposes and may contain dated information.

Soybean producers currently face exceptionally tight margins and uncertainty in the market, creating the need for increased efficiency and return on input investment. Due to improved genetics and production practices, soybean growers are now more aware of the importance of using appropriate seeding rates and seed treatments; this is meant to reduce risk and economically improve yield goals. Seeding rates and seed treatments are influenced by many factors including variety selection, soil conditions, weather forecasts, and cultural practices (row spacing and planting dates).

Before seeding rates can be determined, it may be useful to consider how soybeans respond to increasing or decreasing seeding rates. Soybeans have the ability to "flex," or adjust growth and development, in response to seeding rates and environmental conditions; variation in plant development is often expressed in the amount of branches and pods the soybean plant develops. These alterations in plant development can have beneficial, or detrimental, impacts on yield, harvestability, and pest management. For example, soybeans planted at lower seeding rates produce pods closer to the soil line which can make harvest more difficult; higher seeding rates can produce taller plants with reduced branching and pod formation, reducing yields. It is for these reasons that choosing the appropriate seeding rates is so important to maximize profitability and productivity. Greater plant populations don’t necessarily mean greater yields so this will continue to be a crucial management decision as seed prices continue to rise.

Seed treatment efficacy varies due to seed quality and environmental conditions. In many cases use of a seed treatment with high quality seed has shown little effect on seedling emergence and vigor; however, use of seed treatments on low quality seed can increase field emergence significantly. Environmental conditions during germination can also influence the efficacy of seed treatments; in situations where conditions at planting are conducive, seed treatments may not be effective. Alternatively, if conditions at planting favor disease, seed treatments may be an effective option. Cost and active ingredients for seed treatments are important, so decision making using pest and disease history and active ingredients can go a long way.

To learn more about soybean seeding rates and seed treatments in Northern IL, come to the Highland Community College Soybean Demonstration on Wednesday, August 29th from 9:00 a.m to 11:00 a.m. This event, in partnership with University of Illinois Extension has no fee for attending the program, and will provide breakfast for all attendees who pre-register online before August 24th. The focus of the day will be the soybean plant population (90,000-170,000 seeds/ac) and soybean seed treatment (ILeVO, Lumisena, rhizobial inoculant) trials located on the Highland Community College test plot in Freeport. Extension educators Phillip Alberti and Russ Higgins, and Extension Plant Pathologist Nathan Kleczewski will discuss the research demonstration and discuss issues seen throughout the 2018 growing season.   All persons are welcome to attend this free seminar. If you have questions about this event or need any type of accommodation to attend the event, contact Phillip Alberti, Crop Science Educator with University of Illinois Extension in the College of Agricultural, Consumer, and Environmental Sciences at, 815-235-4125 or on Twitter (@NorthernILCrops). Anyone interested in attending may register online by visiting the Extension website at or by calling the University of Illinois Extension at 815-235-4125.

Source: Phillip Alberti, Extension Educator, Commercial Agriculture,

Pull date: October 21, 2018