Tune your tillage system to produce large uniform ears
Consistency results in real bushels when growing corn. To harvest large uniform ears in the fall, farmers must provide the perfect seedbed in the spring.
Uniform soil density is a vital component of successful corn production, says Farm Journal Associate Field Agronomist Missy Bauer, who spoke on the topic at the 2013 Farm Journal Corn College Fundamentals event in Coldwater, Mich.
Be mindful of how your tillage system affects root growth and water movement, advises Farm Journal Associate Field Agronomist Missy Bauer.
"Corn yields will correlate to soil density," Bauer says. "The more uniform soil density you have, the more moisture you should be able to pull up later in the season, which will equal better corn yields."
Bauer encourages farmers to assess their tillage system and understand how it affects density. "Think about what you’re doing to increase or decrease root growth, water movement and plantability," she says.
"A uniform seedbed allows the planter to run more smoothly in the field, which helps achieve our goal of a high ear count." High ear counts, as well as consistent ear size, are reached by even plant emergence and even plant spacing.
To illustrate the importance of tillage systems, Bauer and her team performed three methods in the same field. Soil pits were dug in different sections so farmers could gauge compaction levels, root growth and moisture levels. Corn ears were pulled from each section so farmers could link the tillage system to actual yield potential.
In one area, a disk was used in the fall and again in the spring, which created horizontal soil density layers. Isaac Ferrie with Crop-Tech Consulting assisted farmers in identifying the pros and cons of this tillage system.
The horizontal tillage sheared the soil horizontally and created abrupt soil-density changes. "You could actually find both disk layers," Ferrie says. "The roots turned when they hit the soil density change, and as a result, they were trapped."
During prolonged dryness, especially in the summer, the roots won’t be able to access the moisture that’s held in the subsoil. In this test area, the ear count was decent and the ears were consistent, but small in size.
In the second area, vertical tillage was performed with a hybrid chisel in the fall followed by a vertical leveling tool in the spring. The roots penetrated down through the soil at a natural 35° to 40° angle, which improved water and nutrient uptake by the plant.
"The soil had uniform shatter and no definitive layers or water lines," Ferrie says. "That created good root growth and water uptake, which equals large and consistent ears."
Vertical tillage was used in the third area, but it wasn’t properly executed. Primary tillage was done with a chisel plow that ran too shallow, which didn’t shatter the soil between the shanks.
"This left hard soil columns," Bauer explains. "When there are columns of untilled ground next to areas of loose soil, it acts as a rumble strip through the field."
An uneven field surface will cause the planter unit to bounce, which doesn’t allow the seed to be planted at consistent depths or spacing. This situation was not conducive to strong root growth, and the soil moisture wasn’t uniform, resulting in uneven growth and a low ear count.
Participants hit the soil pits to assess soil density after various tillage systems at the Corn College Fundamentals course in Coldwater, Mich.
In a no-till or minimum tillage seedbed, soil density is still important. "Remember, the planter feels whatever is underneath," Bauer says. "The goal is to have uniform soil moisture from the top down."
In times of less-than-ideal weather, she adds that uniform soil density is even more critical. "Non-uniform soil makes the plants more suspect to poor drainage during wet weather and prolonged dryness during droughty conditions," Bauer says.
- Early Spring 2014