Among the recent strides in planter technology, adjustable downpressure is a game-changer, says Farm Journal Field Agronomist Ken Ferrie. It, along with today’s sophisticated furrow-closing systems, can set you up for picket-fence stands and photocopied plants, the foundation of ear count and yield.
Here are some tips to help you dial in the ideal settings for your field’s specific soils and conditions.
May The Force Be With You
“Placing seed at uniform depth requires sufficient downforce on the row units to firm soil with the depth wheels, so the seed trench walls stand up and seed can be placed at the bottom,” Ferrie says. “There should be enough downforce to keep units in contact with the ground 97% of the time.
“Insufficient downforce causes uneven depth of planting, which leads to uneven emergence, or dry soil sloughing off the top of the trench onto the seed,” Ferrie continues. “Too much downforce leads to sidewall smearing, which causes the furrow to crack open afterward. In tilled fields that get too mellow, you may need to apply upward pressure because the row unit full of seed is too heavy, causing sidewall smearing issues.”
Hydraulic downpressure control allows downforce to change in a millisecond, by row and by foot of travel. “That’s not too important in conventionally tilled soil where the field cultivator passes 4” deep in mellow conditions,” Ferrie continues. “But it’s very important in no-till or strip-till because soil firmness changes quickly because of soil type, whether you’re in the center or the edge of a strip, wheel tracks and other factors.”
To set downpressure initially, stop the planter with the units in the ground, then see if you can turn both depth wheels on a few row units.
“If you can only turn one of them with the planter in the ground, back off the downforce until you can turn both wheels. At that point, you are not holding planting depth. Add small increments of downforce until it’s difficult to make at least one of the wheels turn. Continue to check depth wheel setting in all soil types or changing conditions,” Ferrie says.
Continue to check behind the planter as soils and conditions change.
“If you find a seam indicating sidewalls are not being crushed, back off the downforce and see if it goes away,” Ferrie advises.
Close the Deal
It’s necessary for your planter’s closing system to do three things:
- Close the furrow from the bottom up, leaving the moist soil at the bottom and the drier soil at the top.
- Crush the sidewall. “If you fail to crush the sidewall, it will result in a seam that will open up later,” Ferrie says.
- Firm soil over the seed, so moisture can’t escape. “Moisture is needed for germination and for development of the first and second sets of crown roots,” Ferrie says. “If it rains a day or two after planting, all will be well. Rain will settle the trench and allow the seed to germinate uniformly. But if you get 30 mph or 40 mph wind and 70˚F to 80˚F temperatures, you can run out of water at planting depth in a few hours. If it doesn’t rain for three weeks, furrows that weren’t firmed will be too dry to form crown roots and you’ll have floppy corn.”
The Best System For You
There are many types of closing wheels, designed to close furrows from the bottom up, crush sidewalls and/or firm soil over the seed.
“Rubber-tire closing wheels’ main function is to firm soil,” Ferrie says. “Cast-iron wheels are designed to close the furrow from the bottom up and firm soil. Spoked wheels’ main function is to crush the sidewall.”
Spoked wheels with swept-back tines are good for sidewall crushing and more soil firming. Twisted tines provide sidewall crushing and bottom-up closing.
“Some closing systems are two-stage,” Ferrie explains. ”They have staggered closing disks or spoked wheels designed to close from the bottom up and crush the sidewall, plus a firming wheel. This has been Case IH’s system from the beginning. There are versions from other companies.
“Two-stage systems provide flexibility if you operate across multiple farming systems, such as no-till, strip-till and conventional tillage. They provide more firming in conventional tillage and more sidewall crushing in no-till.
“Today’s technology lets you adjust your planter to handle conventional, strip-till, no-till and cover crop conditions from the tractor cab,” Ferrie summarizes. “Planter setup is more complicated; but the improved ROI from multiple systems that fit each soil type make it worthwhile.”
No matter how much technology you have inside your cab or planter, Ferrie concludes, “It is still crucial for operators to ground-truth. Dig cross sections of the row, checking depth, sidewall smearing and furrow firming. Thanks to technology, you don’t have to spend as much time on your knees as your dad and grandpa did, but you still need to check each of your fields multiple times.”
Adjust Downforce to Fit Soil Conditions
A Farm Journal study in tilled and no-till conditions illustrated the varying amount of downforce required to keep depth wheels in contact with the surface, firming the soil so trench walls would stand up and seed could be placed at the bottom. In both situations, units exceeded the required 97% ground contact (top photo). In no-till, the average downpressure requirement was 130 lb./ft., compared to 63 lb./ft. in tilled soil.
“Hydraulic downpressure control is especially beneficial in no-till and strip-till because soil firmness changes quickly based on soil type, whether you’re in the center or the edge of a strip, wheel tracks and other factors,” says Farm Journal Field Agronomist Ken Ferrie. “But it’s also valuable in tilled soil, where you sometimes need to apply negative downforce (i.e., upward force), to take some of the weight off the planter units.”
If Your Seedbed Dries Out
“If a seedbed gets dry down to planting depth, it’s almost impossible to get a trench to stand up long enough to get seed to the bottom of the furrow and close it,” says Farm Journal Field Agronomist Ken Ferrie. “Dry surface soil will fall into the furrow before the closing system can operate.
“While this is a seedbed problem, not a planter issue, you can help the situation by changing your planter setup. Lower your row cleaner wheels to push the dry soil to the side and let you plant into moisture. This carries some risk: Your plants will be down in a little valley, so if you get a hard rain before or during emergence, the seed or seedling will be covered when rain washes the soil you pushed aside back into or on top of the row. But the only other option is to delay planting until it rains.”
