During the 2020 growing season, field demonstration plots were planted in five locations in the United States, including Illinois, Minnesota, Ohio, North Dakota and South Dakota. In addition to evaluating the effect of equipment-induced soil compaction at all locations, the AGCO team continued its comparisons of various planting depths, downforce levels and seed singulation on corn yield at the South Dakota, Minnesota and Ohio locations.
“During the past five years, we have conducted more than 50 field comparisons in North America and around the globe demonstrating the importance of proper corn seed placement,” says Jason Lee, AGCO agronomist and farm solutions specialist. “What we’ve shown is that there’s no substitute for getting seed planted into adequate soil moisture at a depth sufficient enough to allow for uniform emergence and good nodal root development.”
The AGCO team compared corn plant performance and yield based on three variables:
- Depth – Corn was planted at six depths ranging from 1 inch to 3.5 inches.
- Downforce – Corn was planted with light downforce, heavy downforce and real-time automatic downforce control provided by DeltaForce® automated downforce from Precision Planting®.
- Spacing – Corn was planted at two singulation rates – 93% and 99% seed spacing accuracy.
Corn was planted with a Fendt Momentum planter pulled by a row-crop tractor running dual tires. All comparisons were planted in 30-inch rows, with the exception of the North Dakota location, where the corn was planted in 22-inch rows.
Takeaway No. 1: Plant into moisture and no less than 1.5 inches deep
Crop Tour comparisons verify there can be yield penalties when corn is planted too shallow or too deep. Plant too shallow (1-inch-deep or less), and the corn plant’s nodal roots will develop at or just below the soil surface. Limited nodal root development is detrimental especially when conditions turn hot and dry. Lee says this was especially evident at the Ohio location where soil was wet at planting, then dry during the growing season. Corn planted 1-inch-deep exhibited more tip-back on the ears than corn in rows planted at 1.5 inches or deeper, due to the combination of poor nodal root development and dry growing conditions.
“When we get tip-back, there is little or no kernel development on the last one or more inches of the ear tip. That’s lost yield potential,” Lee says. “Over the past five years, we found that corn planted 1.5-inches-deep yielded 13 more bushels per acre on average than corn planted 1-inch-deep. At current corn prices, we’re talking about $50 or more in lost return per acre due to planting too shallow.”
In certain conditions, planting too deep can reduce the total number of plants that emerge and cause uneven emergence. Reduced emergence lowers the overall plant population; uneven emergence leads to runt plants that can’t compete with their neighbors for resources. Both reduce yield potential. At the Ohio location, corn planted 3 inches deep yielded 6 bushels per acre more in 2020 than corn planted 3.5 inches deep — a difference that closely mirrors the five-year average.
“Typically, a planting depth of 2 inches will provide the maximum yield potential in most planting conditions. This can vary, however, and adjustments should be made based on soil moisture and the extended weather forecast,” Lee says. “We know that planting depth is a simple adjustment to set, but it’s such a critical piece to maximizing corn yield.”
Takeaway No. 2: Don’t skimp on downforce
Once proper planting depth is determined, it’s crucial that enough downforce is placed on each row unit to maintain that depth. Inconsistent depth control can also lead to uneven corn emergence, resulting in yield loss.
Since 2016, AGCO Crop Tour plots have compared light, heavy and automatic downforce. Too much downforce (right) can create sidewall compaction in the seed trench, which can lead to root development issues, causing yield loss. Crop Tour comparisons show a yield reduction of about 13 bushels per acre when downforce is too light and a 2- to 3-bushel-per-acre penalty for heavy downforce as compared to automatic downforce (left).
“Soil type and condition changes across a field, and growers have different options for maintaining corn seed depth, including spring, air bag and hydraulic downforce systems,” Lee says. “As with planting depth, downforce is a balance. Set it too light, and the seed doesn’t get placed to the right depth because there’s simply not enough force to keep it there. However, too much downforce can create sidewall compaction in the seed trench, which can lead to root development issues.”
During the past five years, AGCO Crop Tour™ trials have compared three downforce protocols: light downforce, heavy downforce and automatic downforce. The results demonstrate that automatic downforce, which adjusts to field conditions in real time, provides a yield advantage.
“On average, when downforce is too light, we see a yield reduction of about 13 bushels per acre when compared to automatic downforce,” Lee says. “By contrast, we see a 2- to 3-bushel-per-acre penalty for heavy downforce. So, if you aren’t running a planter with automatic downforce and want to err on the side of caution, set your downforce on the heavy side.”
Takeaway No. 3: Uniform seed spacing increases yield
In addition to uniform emergence, the uniform spacing of corn plants within the row is crucial to maximizing yield potential. Evenly spaced plants result in equal competition for essential resources, allowing for optimal growth. The result is more bushels per acre.
Uniform spacing of corn plants within the row is crucial to maximizing yield potential. AGCO Crop Tour plots compared 93 percent and 99 percent seed singulation using the vSet metering system. Yield results over five years show that a 6 percent reduction in singulation results in a yield loss of about 5 bushels per acre, a good reason to avoid skips and doubles when planting.
“We want to avoid what are referred to as ‘skips’ and ‘doubles,’” Lee says. “Skips occur when the planter doesn’t drop a seed, resulting in a missing plant and no ear whatsoever. Doubles occur when the planter drops two seeds close together. The result is two smaller ears that don’t produce the same yield as ears from evenly spaced plants.”
A planter’s ability to drop one seed at a time is referred to as seed singulation. Crop Tour field demonstrations have compared plots planted at two singulation rates – 93% and 99% using the vSet® metering system.
“Our five-year data shows that 6% reduction in singulation results in a yield loss of about 5 bushels per acre,” Lee says. “So growers really want to avoid skips and doubles.”
Crop Tour 2021: New year, new questions
Lee adds that while the AGCO team will continue many of the field trials from the past five years, some new questions are likely to be posed in 2021.
“We’re still working out the details, but we would like to do some plots comparing plant populations, the impact of starter fertilizer, as well as differences between types of tractor tires and tracks,” he says. “The whole team is excited to ask new questions, help growers improve their planting practices and ensure their corn crops reach full yield potential.”
For more information about best planting practices and observations from the 2020 AGCO Crop Tour, watch the 2020 Virtual Crop Tour online at https://youtu.be/Viqxt06_NMw. Visit www.fendt.com/us/planters or contact your local dealer to learn more.
