Soybean Seeding Rate x Row Spacing Interactions (location 2)(7.5 vs. 30 inch rows)

Methods

The soybean variety, Rea RX1027, was either seeded in 30 in. wide rows with a planter or in 7.5 in. wide rows with a drill on June 21st.  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.

Results:

The results show a difference between drilled versus 30 inch row beans is insignificant at each planting rate. For example the population of 75,000 seeds/acre showed a difference of 0.4 bushels between 30 inch and 7.5 inch drilled beans and this difference is 87% likely to be due to chance alone. Or it is likely that this yield difference was due to differences in final populations, 77,537 plants/acre (7.5 inch rows) yielded 0.4 less than a final population of 82,474 plants/acre (30 inch rows). Low yield response could also be due to lesser yields associated with the late planting date of June 21st. 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.

Acknowledgements:

Trial funded by South Dakota Soybean Research and Promotion Council

Authors: Thandi Nleya and Graig Reicks