Corn trials highlight need for optimal performance of machinery at planting time

Dan Hansen
Cody Miller, Swiderski Precision Farming specialist, points out the location of the Smart-Depth technology on the corn planter.

WAUPACA, Wis. – After three years of corn and soybean field trials on a farm in western Marathon County, two corn trials were conducted in 2021 on two very different parcels of land in western Waupaca County and near Thorp in Clark County.

The trials were a cooperative effort by Swiderski Equipment, Pioneer Seeds, White Planters, Next Generation Ag Solutions and the Tomorrow Valley Cooperative. 

Crop tour field days were held last August to provide growers with preliminary information on the trials. A final report was made to 70 producers during presentations in Waupaca and Thorp by Mike Gronski, field agronomist with Pioneer Seeds, John Cooper, Precision Farming manager at Swiderski Equipment, and Cody Miller, Swiderski Precision Farming specialist.

Gronski noted that P9193AM™ corn was planted into tilled ground at the Thorp location on May 6, and P9619AM was no-till planted into the Waupaca location on May 7. “Both products are rated at 6 inches or above on emergence,” he added.

At each location a 12-row planter pass ran the length of the field at 1, 1.5, 2 and 3-inch depths. Each location also has a 12-row pass using Smart Depth with planting depths ranging from 1.5–3 inches.


“To determine the impact of in-row singulation on yield, two different plates were used,” Gronski explained. “This included a proven plate with proven 99.6% accuracy and a plate with plugged holes designed to simulate skips and one with extra holes between the factory holes to simulate doubles. These were designed to simulate 95.1% accuracy.”

One replication was recorded for each plate style, and both plates hit their targeted planting population, according to Gronski. The 99% singulation plate provided a 5.3 bushel per acre (bu/ac) average over the 95% singulation plates, and a revenue increase of $26.50 per acre.

“All planters have varying ways to increase or decrease singulation within the seed metering system, so contact your planter manufacturer for the correct maintenance schedule to ensure optimal performance at planting,” Miller advised.

Cody Miller, from left, John Cooper and Mike Gronski  shared the final report on the 2021 corn field trials recently to Wisconsin growers during meetings in Thorp and Waupaca.

Planting populations

The Thorp location was planted at 33.6 thousand seeds per acre, and populations were within one thousand of target on all passes except for the 2.5 and 3-inch depths. Late-emerging plants were most noticeable at 1 and 1.5 inches, with 15 and 5 late-emerging plants per 1/1000th acre.

The Waupaca location was planted at 31.4K; only the Smart Depth and 1.5 and 2-inch trials were within 1K of the target. The lowest population was 28.4 at the 3-inch depth. The most consistent emergence was seen in the Smart Depth pass, while the worst was recorded at 3 inches. “The 2-inch pass was omitted at Waupaca due to fertilizer placement issues,” said Gronski.

Yields in Thorp were optimized at depths from 1.5 to 2 inches, and likely fell off in the Smart Depth pass due to the range going to 3 inches deep and planting conditions deeper than expected.

Yields in Waupaca were optimized at 1.5 inches and with Smart Depth. “Moisture was abundant at this location, leading to a shallower seeding depth,” Gronski noted.

Down pressure effects

Another objective of the trials was to determine the effect of down pressure on grain corn yield and harvest moisture.

“The planter was equipped with Delta Force to enable row units to adjust down pressure precisely, and by row versus traditional springs and bags,” said Miller. "Light, Auto and heavy settings were used. With the light, at 168 pounds, only 50-60% ground contact was detected. The heavy setting was 306 pounds.”

One replication of 12 rows was run for each down-pressure setting. At both sites the Auto setting provided the most uniform stand and the fewest number of late-emerging plants compared with the light and heavy settings.

The variation in yield at Thorp was 4.2 bushels from the best yield at Auto setting to the lowest yield in the heavy setting. “At $5 corn the correct downforce provided a $21 per-acre advantage, said. Gronski.

The Waupaca location had a 20.2 bushel variation between the light and heavy settings. The light and auto settings reported 29k per acre, while the heavy setting recorded 30.5k per acre. The heavy setting translated into a $101 per acre advantage.

“The correct amount of down pressure will vary greatly by planter, technologies used on the planter and ground conditions at planting,” Miller noted.

Furrow Force

A proper seedbed and seed-to-soil contact are critical for the establishments of a uniform stand, according to Miller. “Because soil conditions can vary across a field due to differences in soil types and drainage, Furrow Force™ is designed to help create a uniform seedbed across a broad range of soil conditions,” he stated.

At both trial locations, light (15 pounds), standard (35 pounds) and heavy (55 pounds) passes were made to simulate the impact of varying downforce on planter closing wheel systems and the impact it can have on stand quality and yield.

“Under applying pressure on the closing system significantly decreased yields at both locations,” related Gronski. “Standard pressure yielded the most in worked ground, while applying additional force in the no-till ground increased yield.”

“Planter closing wheel settings will vary by field conditions and equipment. “Monitoring the seedbed throughout planting is crucial to optimizing yields,” Miller advised.

Variable-rate seeding

With continuing advances in planter technology, variable-rate seeding is of interest to many growers

“In this part of the trial variable-rate seeding was based on soil organic matter (OM) percentage recorded by Precision Planting’s Smart Firmer, on a field that has been no-till planted for over 10 years, and following soybeans from 2020,” Miller related.

Four individual passes were planted. One was planted at a flat rate of 29K, another at 32K. The first variable-rate pass ranged from 28-34K, with an OM range of 1-3%; a second pass was planted at a range of 28-34K, with an OM range of 2-3%. 

“The biggest yield advantage came from increasing population in general, but the addition of variable -rate parameters from the first pass versus 32K flat rate added 3.3 bu/ac, or an additional $16.50 in revenue based on $5 corn,” Gronski reported.

When the parameters in the second variable-rate pass were narrowed to better fit the soil properties an additional 2.2 bu/ac, or $11 in revenue was added versus the first variable-rate pass.

“While solid returns were noted with the variable-rate seeding, ideally growers would have a good understanding of their organic matter percentage to help set an ideal range to be expected across the field,” Gronski cautioned.

Starter fertilizer

The 2021 trial also looked at the potential benefits of varied starter fertilizer placement, with the Conceal starter fertilizer system applying varying rates of 16-8-2-1S no-tilled into soybean stubble.

Three rates were used at 20, 25 and 30 gallons. Each rate had a 6-row pass using the dual-placement on each side of the seed, and a traditional single placement the seed for six total passes. 

The dual-banded placement did show more yield potential when fertilizer rates were lower. A 6.9 bu/ac was seen with the dual-band versus the single at 20 gallons per acre.

“The need, rate and placement of starter fertilizer can vary by soil temperature, planting date, hybrid emergence score and previous crop planted on a given field,” Gronski stressed.

John Cooper also assured Swiderski Equipment customers that despite supply-chain issues, the company was taking steps to make sure parts would be available if they needed them for spring planting.

“Now’s the time to check your equipment, and contact us soon if you need anything,” he stressed.