Soybean Seeding Rate x Row Spacing Interactions (location 1) (30 inch rows)

Methods

The soybean variety, Channel 2402, was either seeded in 30 in. wide rows with a planter on June 12th.  The seed was untreated.  Plots were seeded at either 75k, 105k, 135k, 170k, or 205k pure live seeds (PLS) ac^-1.  The 90% germination value from the seed tag was used to calculate PLS.  The 170k seeding rate/30 in. row treatment was excluded from the trial, as we suspect the wrong rate was planted.

Results:

When soybeans in 30 inch rows are compared at different planting populations versus yield; the results are those of a planting population study. For this field 205K  out-yielded 135K, and 135K out yielded 105K, 105K yielded better than 75K. However all of these yield values are statistically the same or similar, so there is no real gain from the increased seeding rates in 30 inch rows, as it appears in this study. A continuation of this study to confirm these findings within different years and different fields is needed to show that for 30 inch rows, yield differences were in fact due to increased seeding rates and not to chance alone. It’s important to note that soybean yield response to seeding rate and row spacing combinations are highly variable and that results from multiple site-years and your own on-farm testing should be taken into consideration when choosing an appropriate seeding method.

Acknowledgement

Authors: Thandi Nleya and Graig Reicks

Trial funded by South Dakota Soybean Research and Promotion Council