We all know now that 100-bushel soybeans are in the realm of possibility. Kip Culler did it first and repeated it three times, topping off at 160 bushels. Dan Arkels and the Lakey family have done it in Illinois. Matt Miles has repeated it five times over five consecutive years in Arkansas. And Randy Dowdy broke 100 bushels in 2014 and 2015 and hit 171.8 bu in 2016. There have been other growers who have broken through this ceiling unofficially, so it is possible.
The key to producing 100-bushel soybeans is to have the right luck with the weather (rainfall or irrigation, moderate temperatures, no hail, late frost), early planting and good soil, and then to follow the best agronomic practices. Below I present 10 tips; take them and put your own spin on them, coming up with a systems approach that will move you up the yield curve.
First, and most importantly, is variety selection. Select the right variety for the right fields and yield potential. Study yield performance reports and look at your own yield data. Select varieties with resistance to SCN, SDS and other diseases.
Second is rotation. A two-year corn followed by one-year soybean rotation will spike yield. Soybean plants face many disease organisms from planting to harvest and with a two-year continuous corn rotation, fewer disease organisms will remain in the soil, plus that extra year of corn adds more organic matter back to the soil.
Third is tillage. Too much tillage doesn’t benefit soybeans. Only in wet, heavy soils do soybeans benefit from tillage by drying out the soil and allowing earlier planting.
Fourth is planting date. Plant early at the end of April and at the same time as corn. Run two planters. Beyond May 1, for every day that planting is delayed up to June 5 there is some yield loss. Plant early and treat your seed to protect it against soil borne diseases.
Fifth is plant population. Growers can push it down when planting in narrow rows to 140,000 to 160,000 or under and save on seed costs and achieve the same yield potential.
Sixth is row spacing. Narrow 15-inch or 20-inch rows outperform 30-inch rows and yield equal to drilling in 7½ inch rows (which wastes seed). Growers save on seed by getting better seed singulation and depth placement and get more even germination and emergence.
Seventh is controlling pests from emergence to pod fill. Know your pest risks, treat your seed and scout regularly. Treat for insects like soybean aphid, bean leaf beetle and Japanese beetle whenever they exceed the threshold. Most high yield producers apply an insecticide and fungicide at R3.
Eighth is weed management. Over 90% of the soybeans planted are glyphosate tolerant, but a number of weeds are now resistant to glyphosate. Use a weed control program that includes a spring burndown or tillage, overlapping residual, and post program that will control herbicide-resistant weeds and spray when weeds are smaller than 4 inches. Early weed competition robs yield.
Ninth is fertility. Fertilize not just for corn, but for soybeans as well and have your soil tests in the medium range. Consider foliar feeding once or twice to stimulate the crop.
Tenth is harvest. Harvest when the crop is ready at 13 to 15% moisture, properly adjust the combine and go slow. Reckless harvesting can lose several bushels per acre.
Agronomist Daniel Davidson, Ph.D. posts blogs on agronomy-related topics. Feel free to contact him at firstname.lastname@example.org or ring him at 402-649-5919.