CAUTION: Do not apply urea, ammonium thiosulfate (12-0-0-26), potassium thiosulfate, or fertilizer containing boron in contact with the seed. Research has not found a need for calcium and magnesium ...

Under no circumstances should urea or urea-based fertilizer be seed-placed with corn. With small grains, you can generally apply 10 pounds of nitrogen as urea with the grain drill at seeding time, ...