Influence of Soybean Seeding Rate at Three Planting Dates

Trial Objective

  • Planting date is an important factor for potential soybean yield. An earlier planting date could be a low-risk/high-return soybean management practice.
  • A generally recommended practice is to increase the seeding rate when soybean planting occurs later in the season.
  • This trial was conducted to determine the effect of the seeding rate on the yield of soybean across three planting dates.

Research Site Details

  • A 3.7 relative maturity group Roundup Ready 2 Xtend® soybean product was planted at three planting dates (April 25th, May 23rd, and June 4th) and four different seeding rates (60,000, 100,000, 140,000, and 180,000 seeds/acre).
  • There were two replications for each treatment, all replications received the same weed management program.

Understanding the Results

  • The average yields increased with earlier planting dates. The average yields across all seeding rates for the April 25th, May 23rd, and June 4th planting dates were 74.2, 71.7, and 66.6 bu/acre, respectively.
  • The 140,000 seeds/acre seeding rate provided the highest yield at the earliest and mid-planting dates. At the latest planting date, there was only a 2.5 bu/acre difference in average yield between all seeding rates. 



What Does This Mean for Your Farm?

  • Our studies at the Bayer Learning Center at Monmouth, IL generally agree with regional University planting date studies in that early planting of soybean tends to provide a higher yield potential than later planting.
  • Early planting assumes that the soil and weather conditions are suitable for seedbed preparation and seed germination; the actual planting date will vary year to year based on weather and field conditions.
  • Contact your District Sales Manager or Technical Agronomist for planting recommendations.
  • For this specific site and testing year there was no observed influence in different seeding rates and planting dates and this study will be repeated again in 2019.
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