Many growers can save money by dropping soybean seeding rates in 2018.

We have seen a big decline in soybean seeding rates over the last three decades. Growers were dropping 200,000+. Then Roundup Ready^® was released and we had to depend less on row spacing and population to control weeds and rates dropped to 160,000 to 180,000. Then seed costs went up and seed was being sold at 140,000 seeds per unit and seed rates dropped to 140,000 to 160,000. Many growers still want the insurance of a good stand that comes with a higher seeding rate if some seeds fail to establish.

But things have changed, and soybean producers might save money on seed costs by lowering their seeding rates today. More and more long-term experiments are proving that reduced seeding rates still optimize yield. And research has shown that 100,000 plants per acre at harvest, well distributed, will optimize yield. The broad adoption of seed treatments on soybeans should ensure you can drop your seed rate maybe 10 to 15 percent.

Marion Calmer with Calmer Cornheads and the Calmer Ag Research Center has been studying soybean row spacing populations for many years. His population data from his Alpha, Ill., farm shows that planting population has little effect on final yield. He wrote, “At my farm, from 2010 – 2015, 50K was the most profitable population to plant soybeans at $60/bag, this is approx. $10 for 25K seeds. Soybean value at $10/bu.”

In a recent Hoosier Ag Today article, Jim Schwartz, director of PFR and agronomy at Beck’s Hybrids, said, “We continue to see that the economic optimum seeding rates for soybeans tends to be a little bit lower than many growers might be planting. We see that 125 to that 100,000 seeds per acre to be the economic optimum seeding rate, and yet we still have a lot of growers who are planting 150, 160, 170,00.”

Becks is encouraging growers to test different rates on their own. “We’re not saying go plant 100,000 or even 115,000 or 120,000. What we are saying is if you are planting in that 160,000 – 180,000 seeding rates, every 10,000 seeds that you cut back can save you around $4 per acre. So, we think if you’re at 160, why don’t you try planting some strips in fields at 150 or 140, save yourself $8 – 10 per acre, and you’re not going to sacrifice hardly any yield. Our data would say, and we’re pretty confident in this multi-year, multi-location data, you’re not going to sacrifice yield, but you are going to improve your economics.”

At the recent Resilient Farmer Roadshow event, where experts talked about risk management in production ag, I spoke on variable costs and achieving a return on investment. If seed costs $73 per unit (naked seed $60 and $13 for a fungicide and insecticide per unit), it costs $73 per acre for seed at 140,000—if we consider 140,000 an optimal population with added ‘seed’ insurance for a good stand. If you drop the rate to 120,000 you are saving $10.43 per acre. If you increase the population to 160,000, it is costing you an additional $10.43 with no economic benefit.

If you are planting more than 140,000, time to drop it back to a unit per acre and see how it works. If you are comfortably planting 140,000 and using seed treatments, it is time to drop it down to 130,000 and see how it works. Saving on seed costs per acre is one strategy for adding additional profitability to your bottom line.

Soybean agronomist Daniel Davidson, Ph.D. posts blogs on agronomy-related topics. Feel free to contact him at djdavidson@agwrite.com or ring him at 402-649-5919.