Smarter Every Season

The Essentials of Uniform Emergence

(Progressive Farmer image provided by Precision Planting)

Norm Dresbach knows the value of preventing skips and doubles as he evaluates the stand of corn in his fields near Circleville, Ohio. He's had a long working relationship with Precision Planting, and now regularly surpasses 99% accuracy in seed singulation.

But there's something else that he's discovered as he gets down on hands and knees to evaluate his germinating corn crop. Dresbach uses colored flags to mark the time of emergence on some fields, and follows the development of those plants through the growing season.

"As important as it is to achieve a picket-fence stand," he says, "it may be even more important to achieve uniform emergence. If I plant 35,000 seeds per acre, I want to see 35,000 seedlings emerging at the same time."

The mathematics are hard to argue. Dresbach points out that, in his own experience and supported by research data, it's not uncommon for ear weight to drop by a half-ounce on a plant that emerges just 24 hours after its neighboring seedlings. "If you plant a population of 32,000, losing a half-ounce per ear adds up to more than 17 bushels an acre," Dresbach points out. "What's worse, a corn plant that emerges more than 72 hours behind schedule competes for moisture and nutrients but produces very little yield. In fact, it's more like a weed. And it's not good business to grow weeds."


The germination process seems simple enough -- put a seed in the ground, and let it accumulate moisture and heat units to power the young seedling through the surface. As research agronomist in research and development at Precision Planting, Cory Muhlbauer says that placing a seed in optimal conditions can be challenging in the real world. "Seed germination is a fairly simple process, but it's hard to maintain perfect conditions in a field environment where there are so many dynamic factors. Optimal seeding depth, for example, can change from field to field, or even within a field based on soil type, the amount and distribution of residue, and the quality of a previous tillage pass."

The key for a corn grower, Muhlbauer suggests, is to find the optimal planting depth based on soil moisture, and then maximize the transfer of heat and moisture by providing good seed-to-soil contact -- and top it off with a closing system that firms soil around the seed without compacting the sidewalls of the seed trench.

"I like to think of the seed trench environment from an electrical perspective," he says. "We need to provide a good conductor of heat and moisture to that seed, as opposed to leaving air gaps or residue in the way, which would act more as an insulator. Consistency and uniformity of the stand relates directly to how well we achieve that transfer of moisture and heat. There are several management techniques, knobs that can be turned, to optimize conditions as the planter travels across the field."

One important "knob" that sometimes gets overlooked is the one that controls downforce on the planter. AGCO, the parent company of Precision Planting that installs Precision Planting components on new White planters, compared Precision Planting's automatic, individual-row downforce control called DeltaForce against planters set up with either light downforce or heavy downforce pressure. In trials covering two growing seasons across 11 locations, the automatic DeltaForce improved yields by 5 bushels per acre compared with the heavy downforce planter, and boosted yields by 14 bushels per acre compared to a planter set up with light downforce.

"DeltaForce allows row units to run at the intended planting depth all the time by overcoming changes in soil density (hard or soft soil conditions) within a field, on the fly," Muhlbauer points out. "DeltaForce is a key component that allows a corn grower to get all the seeds planted at optimal depth."

Ohio grower Dresbach agrees that DeltaForce plays a big role in uniform emergence. "A few years ago, just after we had installed DeltaForce on our planter, we went into a field where we had used three different tillage passes," he recalls. Dresbach was amazed at the downforce map that stitched together during the planting pass. "The colors jumped out at us," he says. "DeltaForce varied the downforce from a negative 50 pounds in the soft conditions all the way up to 450 pounds for hard ground. We saw uniform emergence across the whole field, and when we shelled the corn that fall, we saw uniform ears. That sold us on DeltaForce."

In fact, when the farm decided to add a dedicated soybean planter, it also was fitted with the automatic downforce control. "We think there is value in having good depth control and uniform emergence in the soybean crop as well," Dresbach adds.


Muhlbauer says several Precision Planting products use a high-tech approach to help address the constantly changing conditions within a field. "We have a product called CleanSweep that allows the customer to adjust row cleaners from the cab," he says. CleanSweep uses air cylinders on each row cleaner, allowing a corn grower to be more aggressive with row cleaners, or run them lighter if conditions change. "Residue in the seed trench is one of the big factors in taking away from uniform germination and emergence," Muhlbauer adds.

The planting pass is arguably the most important trip across the field each year -- but critical adjustments often are based only on digging in a few spots in a field with a pocketknife to evaluate conditions in the seed trench. "That really pushed us to put eyes in the seed furrow so we could measure the factors that are critical to seed germination," Muhlbauer says. "And we wanted something that could do it on the fly."

The result of that effort is called the SmartFirmer. This device, which replaces a typical seed firmer, puts optics in the furrow and provides information on critical metrics such as seed-available moisture, soil temperature, and the amount of residue showing up in the seed trench (the "clean furrow" metric). The SmartFirmer also measures and documents soil organic matter.

"The SmartFirmer allows us to understand 100% of the time what condition we are dropping the seed," Muhlbauer says. "The operator can see right on the 20|20 monitor whether there is enough moisture, or too much, in the seed furrow, and whether planting depth needs to be adjusted in order to optimize the seed environment."

Another high-tech helper called SmartDepth ties in with the SmartFirmer to provide on-the-fly electronic depth control for each row unit. The operator sets a maximum and minimum depth, and SmartDepth provides automatic depth-control based on the SmartFirmer's furrow-moisture metric to guide how shallow or deep the row unit runs in order to optimize the germination environment. SmartDepth is in beta testing for the 2020 season.


A new product on the horizon to help optimize emergence is Precision Planting's new closing system called FurrowForce. "The factor that finishes off the quest for uniform emergence is to provide optimum density of the soil surrounding that seed," Muhlbauer adds.

FurrowForce automates the closing process; notched wheels work the soil inward, followed by stitch wheels that firm the soil. A closing load sensor links the two stages, sensing weight on the stitch wheels and reporting it to the 20|20 monitor.

These are the kinds of technology that allow Ohio corn grower Dresbach to meet his goal of farming by the inch. "It takes good data to farm by the inch," he says. "Getting good data in real time lets us make decisions that improve our agronomics, and that all begins with a good, uniform stand."


Past Issues