From a seed packet labeled “Blue corn” (didn’t end up turning out well)

You can use a balanced fertilizer (same number across NPK values, like 10-10-10) if that's what you have. If you were buying something, I'd go with like a 6-3-3, or similar. Ideally, an organic fortified with ammonium sulphate (if my guess about your soil being alkaline is correct). There's quite a few kiln dried manure products made this way. Might ask at a local turf supply shop. They're gaining popularity and shops like that have large bags at good prices. Organic inputs tend to have micronutrients and supply what the soil bacteria need to improve the soil over time. They're like concentrated compost, in a sense. Problem with compost is you need a lot of it, by comparison, but it's better for soil health most of the time.

Spacing is pretty important, too. You want corn spaced about a foot apart.

I tried to attach a photo of some corn I grew last year... will see if that works.
2023 - 6 foot+ corn stalks a few weeks before harvest