Seed depth and skips studied in corn plots

Alice Manette
Corn production testing by AGCO found that being able to control the proper downforce in planting depth made a big difference in yield at harvest time in corn tour plots located near Haven this past year.

An international manufacturer and distributor of agricultural products for farmers, AGCO, conducted corn yield crop testing at crop tour plots near Haven. The company announced in early January that by using best planting practices they boosted yield.
“Even with compaction and water-ponding issues in different areas of the field from all the excess spring moisture, we were able to grow a crop and get useful measurements that tell a story,” said Mark Brewster, AGCO product specialist.
The side-by-side comparison plots, planted April 15 and harvested Sept. 25, were the center of an agronomic demonstration hosted by Schmidt & Sons equipment dealership in Mount Hope. Area growers attended an AGCO Crop Tour field day at the plots on July 23, one of several held around the country, to see the plant variations visible at that point in the season.
According to AGCO, in the downforce comparison, using too little or too much downforce in corn planted 2 inches deep decreased yield from 16 to 33 bushels an acre, compared to using the proper amount of downforce provided through automated downforce control from precision planting. The company used their DeltaForce equipment for this planting.
“Being able to control downforce on the go to apply the proper amount made a huge difference,” Brewster said.
Proper downforce while planting is necessary to maintain the uniform planting depth necessary for uniform emergence and better yields, the company said. Because conditions such as terrain, soil texture and moisture vary across a field, the company used a special machine that had active downforce control, which adjusted automatically to optimize gauge wheel load for accurate seeding depth without causing side-wall compaction. AGCO said this equipment also minimized row unit bounce and vibration in rough terrain.
Brewster said because the fields were tilled too wet in fall 2018 and again the following spring, planting the plots at seven different depths was a challenge.
“There was a lot of residue in the top two inches of the soil,” he said. “It’s important to plant into a clean furrow or trench, because we don’t want to plant into the residue and give seed a poor start and have uneven emergence because residue is wicking moisture away from the seed.”
Planting at least 2-inches deep usually provides the seed with good conditions for proper germination, Brewster said. However, he said, seeding depth should be changed based on soil conditions, particularly if soils are dry; in which case, seeds may need to be planted slightly deeper to locate consistent moisture.
During the test crops harvest, the top yields were in rows planted 2 inches and 2.25 inches deep, both producing around 265 bushels per acre. The yield at the shallowest planting depth, 1 inch, was nearly 31 bushels lower, even with adequate moisture.
Another test crop had two seeds drop at once and mimicked a blockage that caused skips within a row. This test crop, by varying seed dropping, found that by using the same population and increasing skips and doubles, there was a considerable yield reduction.
Jason Lee, AGCO agronomist for North America, said that while growers can’t control extreme weather patterns, “one thing we can do is ensure that we are making the correct management decisions to help our crops withstand stress as best we can.”
“So much of that starts at planting – making sure that seeds are properly singulated and evenly spaced, planted at a consistent depth and into consistent moisture for uniform seedling emergence, with a solid soil fertility plan, good soil and residue management, and minimal compaction,” he said. “These are some things we can control to minimize stress during stand establishment and help crops tolerate stressful growing conditions.”