Corn School: Think ‘firming force’ not downforce at planting

Kearney Planters operations manager Cullen Tinline

What’s a planter supposed to do when it rolls into fields and tucks into a fit seedbed?

On this episode of RealAgriculture Corn School, Kearney Planters operations manager Cullen Tinline shares a corn planter furrow management wish list and what growers should expect if their planter is fine-tuned, properly prepped, and rolling in good soil conditions. He also discusses why growers should think ‘firming force’ not downforce when fine-tuning the planter.

In a perfect planting world, Tinline says moisture would be available to the seed as it’s planted at the targeted depth; seed trench side walls are firm enough to hold together so no dry dirt falls in and around the seed; seed can fall into the bottom of the trench; there is no residue close to the seed; and the side walls are loose enough to allow the closing system to demolish the furrow.

But growers need more than luck to get all that right. In the video, Tinline reviews a checklist for planter inspection and offers maintenance and preparation tips for growers as they get ready to head to the field.

Tinline also looks at the importance of downforce and explains why he encourages grower to think more in terms of firming force. He says growers really need to consider soil type and planting conditions when deciding how much down pressure is needed. Story continues after the video.

“It takes little pressure to get the planter to depth in a sandy soil, but how do your sidewalls hold up? Do they have structure that allows the seed to reach the bottom of the trench without caving in?” asks Tinline. “The same can be said for lower-moisture and cloddy soils — they need a little more pressure to keep sidewall structure,” he notes.

With higher speed, growers need more firming force: “Think of it as a water skier behind a boat. The faster we go the more he comes out of the water.”

See Related: Prepping the planter for peak performance

When it comes to heavier soils, Tinline would rather see less force. “Sure, it takes more force to penetrate the soil and reach depth, but after that does it take any to firm the furrow?” he asks. The answer is no — too much force here is like “lining the sides of the trench with bricks.”

Tinline notes that growers tend to lean to the the heavy side to ensure they reach targetted depth but he believes proper firming force correlates directly to good soil structure. “If we have it right, we create the best environment for root growth and nutrient uptake, resulting in even emergence and higher yields.”

Overall, Tinline stresses that every planting system requires active management and balance: “It isn’t a set-it-and-forget-it decision.”

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