Soybean planting rate, row spacing recommendations updated
Across North Dakota and row spacings, the planting rate of about 170,00 pure live seeds (PLS) per acre optimized soybean seed yield.
Following years of field research on soybean planting rates and/or row spacing, North Dakota State University Extension agronomists are updating their recommendations for establishing soybean stands.
Their long-term recommendation has been 150,000 plants per acre across row spacings.
In 2020, Greg Endres and Hans Kandel, NDSU Extension agronomists, compiled and evaluated data from 37 NDSU trials conducted during 2008 through 2019 across the state.
“The objective was to provide a more precise guide for establishing soybean stands, using seed yield response data among regions in the state, based on the combination of planting rates and row spacings,” Endres says.
This work resulted in the NDSU Extension publication “Soybean Response to Planting Rates and Row Spacings in North Dakota” (A1961). It’s available at https://tinyurl.com/9kzey2pj .
Here is a summary of the research data:
- Across North Dakota and row spacings, the planting rate of about 170,00 pure live seeds (PLS) per acre optimized soybean seed yield. In eastern North Dakota trials, 8% of planted PLS per acre did not develop into viable soybean plants. Assuming 8% of PLS do not result in established plants across North Dakota, and using 170,000 PLS per acre, about 155,000 plants per acre would be expected to maximize yield. Within regions, optimum yield occurred with 180,000 and about 140,000 PLS per acre in eastern and western North Dakota, respectively.
- Across North Dakota or by regions, narrow rows (less than 15 inches) consistently provided greatest soybean yield.
Factor Combination (by regions)
- In eastern North Dakota, the combination of narrow rows (12 to 14 inches) and planting rates of about 170,000 PLS per acre provided optimum yield. If planting in wide rows (24 to 30 inches), planting rates to reach the optimum yield were about 190,000 PLS per acre.
- In western North Dakota, the combination of narrow rows (7 to 10 inches) and planting rates of about 150,000 PLS per acre provided optimum yield.
“Note that the recommended planting rates are for optimum yield,” Kandel says. “Economic yield also must be considered based on seed costs and soybean market prices.”