Just when we thought we knew virtually everything about growing corn, scientists keep on finding new things about growing this amazing crop. Most farmers plant corn seed between 2 to 2.5 inches deep. However, new evidence suggests that we should be planting corn seed even deeper.
• Research studies conducted in Indiana recently found that it may be better to plant corn even deeper rather than shallower to get more consistent results. Generally, deep means 3 inches or more and shallower means less than 1.5 inches.
• Paul Jasa, an Extension Ag Engineer for the University of Nebraska indicated that his research with no-till planting indicated that corn should be planted at around 3 inches depth, particularly in continuous no-till planting. They got more consistent results from deeper plantings than shallower planting. In their continuous no-till trials in Nebraska, corn planted three inches deep yielded 217 bushels per acre, and corn planted 2.25 inches deep yielded 199 bushels per acre.
• How is yield affected by the depth of planting? According to Jasa, it may have to do with rooting and root development. If roots are shallow because of shallow planting depth, there may be more issues with roots doing their job. Later in the season before harvest, even standability might be affected by the planting depth.
• If you run into clumps of residue and the planter is set to plant shallow, the seed may not get good seed-to-soil contact. However, if you are planting three inches deep, there are better odds that the disk openers will penetrate the residue and plant the seed in actual soil.
• No, I am not recommending that you should plant all your corn at three or more inches depth, but you might want to compare shallower planting with deeper planting in small plots on your farm this year.