Opportunities exist for farmers to increase soybean yield and profitability by selecting row spacing and seeding rates. A study was conducted by NDSU with selected intensive management practices and inputs to examine potential increases in yield and profit. The study consisted of a series of nine trials conducted during 2008 to 2011 at the NDSU Carrington Research Extension Center and research sites in Prosper and Fargo.

Each year two different Roundup Ready varieties with maturity group ranges of 0.0 to 0.2 and 0.6 to 0.8, were planted. Planting rates were 150,000 and 200,000 pure live seeds (pls)/acre. Row spacings were 14 and 28 inches. Best management practices were used for soybean production during the study. The study’s average early season (2 to 4 weeks after planting) established soybean stand was 130,500 plants/acre with the planting rate of 150,000 pls/acre and 163,800 plants/acre with 200,000 pls/acre. Percent of established plants compared to planting rate was 87% with the lower planting rate and 82% with the high planting rate.

Soybean row spacing and seeding rateTable 1 provides soybean seed yield with row spacings and planting rates for each trial. Averaged across the nine trials, the study indicates the following yield advantages:

*1.4 bu/acre with 14-inch versus 28-inch rows,

*1.4 bu/acre with planting 200,000 pls/acre versus 150,000 pls/acre.

Averaged across the nine trials, the study indicates the following revenue advantages:

*$14/acre with 14-inch vs. 28-inch rows,

*$3/acre with the low vs. high planting rate.

Soybean yield was 2.6 bu/acre (5%) greater with the later maturity group (50.5 bu/acre) compared to the early maturity group (47.9 bu/acre).

Summary

  • While using pure live seed as a basis for reaching a targeted plant population also consider that an additional 10 to 20% seedling loss can occur from planting to emergence.
  • Soybean yield increased with 14-inch versus 28-inch rows and 200,000 versus 150,000 pls/acre planting rate. The narrow rows had higher net revenue than 28-inch rows. Net revenue between seeding rates was only $3 different (Table 1).
  • Full season maturity varieties had higher yield than early maturing varieties.

For more information see publication A1718 - Selected Management Factors for Economically Increasing Soybean Yield.

 Primary funding source for this study was the North Dakota Soybean Council.