By now phones are probably ringing off the hook – or to put it more correctly, beeping and making whatever noise a person's cell phone makes – in Extension offices and in the offices of seed dealers and consultants around the state. The comment and question will be the same in many cases. My corn isn't coming up very evenly… will there be enough plants to make a crop or should I tear up the stand?
The culprit, as Bob Nielsen has noted in various columns earlier this spring, is that many planters started rolling when soils were still at or below the crucial 50 degree level for seed germination. Nielsen is the Purdue University Extension corn specialist. If they did germinate the first drink of water many plants imbibed was cooler than normal. That can cause some reactions with the plant that aren't favorable to early growth, depending on how cool the situation is.
Some started planting early but didn't want the seed down deep in cool soil, so they opted for the one and one-half to two-inch depth. That may have been OK unless forecasted rains didn't materialize, as they didn't in early May in most cases, and winds dried out the soil, leaving the seed either without enough moisture to germinate, or leaving some seed with enough moisture and some not the worst possible scenario.
The other problem with erring on the shallow side is if residue in the field still on the surface interfered with the planting process. If the unit didn't cut through that residue to get seed at a uniform depth, it may have been left at a more shallow depth than where there was more crop residue lying over the row.
The bottom line is that I saw corn planted at a lot of different depths this spring. It was a decision everyone had to make, and this year it may have been as important as deciding when to start planting. Time will tell if depth of planting is indeed a big factor in stand establishment and final yield this year.