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Study shows that soybeans respond to the right downforce per row as well as corn does.

Tom J Bechman 1, Editor, Indiana Prairie Farmer

April 19, 2021

3 Min Read
precision planting planter
PROPER PLACEMENT: Getting soybeans placed correctly with the right amount of downforce is as critical as it is for corn.Tom J Bechman

Many people have accepted the idea that obtaining proper downforce on each row can improve uniformity of emergence in corn and increase yields. New research studies indicate achieving proper downforce is also important for soybeans.

In fact, it is critical enough that it can increase soybean yields and contribute toward paying off newer technology needed to better control downforce row by row.

“When downforce matches field conditions, the depth of planting is consistent and correct,” says Jason Webster, manager of the Precision Technology Institute near Pontiac, Ill. Precision Planting, which offers DeltaForce for hydraulic row-by-row downforce control, operates PTI.

“Too light of row unit downforce causes planting depth to shallow up, potentially placing seed in dry soil, creating poorly rooted plants that struggle for water and nutrients,” Webster explains. “Conversely, too much downforce can lead to furrow sidewall compaction, also creating an environment that can cause limited plant access to water and nutrients.”

Soybean test

In 2020, Webster and his crew set up a test to compare too little downforce on row units to both the correct amount and too much downforce. The correct amount was determined by setting the DeltaForce system in the automatic mode and allowing each row unit to adjust individually and automatically to exert the right amount of downforce. For the “too light” and “too heavy” passes, downforces were kept at pre-set levels all the time. The target planting depth in all three cases was 1.75 inches.

Not applying enough downforce cut soybean yields by 3.5 bushels per acre compared to the automatic setting. Too much downforce dropped yields 2.3 bushels per acre. Economic losses compared to the automatic setting for too light and too heavy, respectively, were $34.13 and $22.42 per acre. Note that running a planter with other kinds of downforce controls was not part of the study. It’s possible that systems that don’t keep downforce consistent could have affected results even more.

If you have 1,000 acres of soybeans and had automatic downforce compared to running with downforce that’s too light, based on this study, you could gain $34,130 in a year toward the better system. If you run too heavy, increased revenue with systems that adjust downforce on 1,000 acres would be $22,420.

Keeton seed firmers

The PTI also tested just how much simple Keeton seed firmers, the plastic beaver-tails that cost $35 per row, can aid in getting more consistent stands and in improving yields. These seed firmers have been available for a long time.

The study found a 1.4-bushel-per-acre advantage for simply running Keeton seed firmers vs. not running them. With soybeans at $9.75 per bushel and Keeton seed firmers with quick-attach brackets at $35 per row for a 16-row planter, you would pay for the seed firmers after running the first 41 acres.

What if you don’t yet have downforce figured out on your planter, but have Keeton seed firmers? The study found that if downforce was too light, but you added Keeton seed firmers on the planter, you could pick up 0.9 bushel per acre. At the $9.75 per bushel price for soybeans, that would still bump income $8.78 per acre.

About the Author(s)

Tom J Bechman 1

Editor, Indiana Prairie Farmer

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