If it was really super dry, guys would have shovels right in front of the openers. Literally make a small ditch about 2-3 inches deep then jamb the seed into moisture. There were ditching shovels behind and between the seed rows.

After the first irrigation (rill) a pass with the cultivator using disks to throw dirt back up against the stalk never knew how deep the seed was planted.

 Just how things are/were done here with sweet corn and really dry ground. Probably no relationship to planting corn in different area's of the country?