Ray is right -

Sometimes people suggest a little Nitrogen at planting for clover (for a boost) - but chances are - in Illinois - your soil will be fertile enough that CLover will flourish without any additional Nitrogen.

Adding Nitrogen at planting (especally on overseeded plots) tends to help weeds/grasses grow faster and compete with clover.

Clover is a legume - and its roots system obatains Nitrogen from the air - for its growth. It does this through a symbiotic relationship with a bacteria - that is present in the inoculant. Most clover blends for food plots are coated with an inoculant - you can also buy a powdered inoculant to mix with the seeds if not.

FH