Soybean Seeding Rate x Row Spacing Interactions (location 1) (7.5 inch rows)

Methods

The soybean variety, Channel 2402, was seeded  in 7.5 in. wide rows with a drill on June 12.  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 drilled beans in 7.5 inch rows are compared at different planting populations versus yield; the results are those of a planting population study. For this field 205,000 seeds/acre strip out yielded 135,000 and 105,000 seeds/acre by 6.8 bushels, in which the 135K and 105k had statistically similar yields. However, the increased seeding rate may not be justified with nearly double the seed costs needed to achieve the 6.8 bushel increase. Not surprisingly 105K yielded better than 75K. However the 170K yielded worse than the 105K and 135K. It is more valuable to analyze which yield differences were statistically the same or different.

Acknowledgements:

Authors: Thandi Nleya and Graig Reicks

Trial funded by South Dakota Soybean Research and Promotion Council