Database Research Summaries
2018 Assessment of Soybean Plant Population and Planting Date Impact on Performance in Western & Central North Dakota

calendar_today Year of Research: 2018
update Posted On: 12/05/2019
group Jasper M. Teboh (Principal Investigator, North Dakota State University, Carrington Research Extension Center)
bookmark North Dakota Soybean Council

Research Focus

The focus of this project is to identify which maturity group to use when farming operations and environmental conditions will allow for early planting, or prevents early planting until a later date.


  • Assessment of the effects of planting dates on soybean performance under dry land and irrigated conditions.
  • Determination of the impact of three practicable seeding rates on yields and economic return.
  • Evaluation of how early or late maturity (maturity group) soybean might impact seed yields.


  1. Average yield at Hettinger was 34 bushels. There was no statistically significant effect of treatment interactions on yields. Yields were significantly better with early planting (27 bushels) than late planting (22 bushels). Yields from the later maturity group variety (MG-0.8) were significantly greater by two bushels compared to MG-0.2 (23 bushels).
  2. Under irrigation, yields were significantly greater at early (59 bu/ac) and normal (58 bu/ac) planting dates compared to yields at late planting (50 bu/ac). Higher seeding rates led to higher yields from 53 bushels at 150K to 56 bushels at 175K, and to 58 bushels at 200K. Yields were however, significantly different only between 150K and 200K. Under irrigation, where moisture was adequate, yields at 200K were likely unaffected by moisture stress, which probably explained higher yields (56 bu/ac) under irrigation compared to dry land (49 bu/ac).
  3. Yields under dry land were less compared to irrigated soybeans. There was an interactive effect of MG and date on yields. Planting early yielded more than later planting. However, the only difference of significance was the yield produced by MG-0.8 (56 bushels) compared to any other treatment or treatment combinations. The general trend was that the further the delay in planting.
  4. Average yield was quite low (25 bushels) due to drought effects. Planting date or population did not significantly impact yields. Meanwhile, maturity group had significant effect on yields. The yield of the early maturity variety (MG-0.2) was 26.6 bushels, which was significantly greater than the 24.2 bushels produced by MG-0.8 variety.



This research will provide North Dakota farmers with results that demonstrate and serve as a guide to the producers, which maturity group soybean category or seeding population is likely to work for them, when planting is early or later than normally practiced.


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

Funded in part by the soybean checkoff.