Planting depth is no place to get creative if you want to achieve uniform stands and optimize no-till corn yields. Paul Jasa, University of Nebraska Extension ag engineer, believes uniformity should be every grower’s goal.

“Uniform seed placement depth produces uniform emergence,” Jasa says. “Uniform emergence can be critical — even more important than uniform spacing. Corn plants coming up at the same time are equally competitive for nutrients, water and sunlight. They have the same time to access those essentials and start well.

“When a plant develops ahead of its neighbor, it hurts yield dramatically. It’s going to vary somewhat from year to year, but a plant lagging behind those around it becomes a weed.

Achieving uniformity, Jasa asserts, requires a year-round commitment.

“I tell farmers they need to think uniformity each day of the year,” he says. “It’s not something you can address only at planting time since it can be affected by numerous factors.”

Uneven Depth Drags Yield

The yield payoff from uniform planting depth can be big. In an ongoing research trial, Jasa has compared the yield impact of uneven plant spacing versus uneven planting depth.

For spacing, treatments averaged the same population, based on 8 inches between plants. However, the inches between plants varied at 2-10-10-10; 6-6-6-14; 4-12-4-12; 4-8-8-12 and a uniform 8-8-8-8.

In 2007, the variations achieved from 85% to 99% of the yield produced by perfectly spaced 8-8-8-8-inch treatments. When planting depth varied from 1 to 3 inches and emergence was delayed 5…