Database Research Summaries
2018 Development of a New and Improved Soybean Staging System

calendar_today Year of Research: 2018
update Posted On: 12/05/2019
group Laura Lindsey (Principal Investigator, The Ohio State University)
bookmark Ohio Soybean Council

Research Focus

The focus of this project is to identify a system that decreases the current variability in the suggested number of days spent in a particular growth stage. Once a potential new staging system is identified, participation and input from other soybean researchers from across the country will be sought to further validate and refine the system.


  • Simplify the current growth stage indicators.
  • Use the revised stages to better describe soybean seed-fill duration.
  • Revise the definition of physiological maturity and harvest maturity.
  • Develop a new way to designate maturity groups that reflects the duration of the growing season.
  • Define and assign the role of determinacy (eg determinate, indeterminate, and semi-determinate).


  1. Plot maps were created and the study was planted. Twice per week, soybean growth stages were recorded. Once per week, the number of nodes on three soybean plants was counted in each plot.
  2. Node counts were conducted weekly and soybeans were staged twice weekly. At the R7 and R8 growth stages, 10 plants per plot were collected and threshed. Wet weight and dry were recorded.
  3. We continued to stage the plots twice weekly until the first killing frost. At the R7 and R8 growth stages, grain samples were collected to determine dry matter accumulation. Plots were harvested and grain samples sent to Minnesota for quality analysis.


Determining the correct growth stage is essential for: 1) Appropriate and legal application of post-applied products, 2) Estimating yield potential or yield loss due to crop injury (hail), disease (SDS), or defoliation from insect feeding, 3) Proper timing and increased ROI for fungicide use (e.g. white mold application timing), 4) Estimating maturity dates under late planting, double crop.

For more information about this research project, please visit the National Soybean Checkoff Research Database.

Funded in part by the soybean checkoff.