One benefit we get from following a field all year long in our Crop Watch '13 program is that we get to see how trends or damage turns out over time. Three weeks ago – just days after the field was sidedressed – there was damage on the end rows. It wasn't more than normal; if you go through the field with a big tractor, applicator and nitrogen tank, you're going to run over some plants and knock others over. Corn was at the V4 stage, about 6 inches tall, when the sidedress application to complete the nitrogen package for the year on the field occurred.
A trip back to the field just a few days ago revealed that in most cases, where corn was damaged from a tire track on the end rows, it was growing back. Some of the plants were green and nearly normal height again. Some may be somewhat behind now, but since they generally come in groups of 4, 5 or 6 plants in a row, and aren't competing with taller plants, they could still produce effectively.
There were a few cases where the plant wasn't going to grow back, but those were in the minority. For the most part, it appeared that the next result of the trip through the field itself to apply nitrogen was going to turn out to be less of a yield hit than it might have appeared to be just a few short weeks ago.
The benefits of sidedressing include getting the bulk of the N on closer to when the plant will use it. That cuts down on the chances that N will be lost due to leaching or other methods. With the wet spring, N that was applied in the fall or even early spring may not all be there now. Some losses may have occurred.