Do a soil test, they are relatively inexpensive. I have never done one but I am going to test this year after done selling corn. Also do a ph test as some plants prefer certain range of PH. Ph test may come with soil test.
https://www.dairylandlabs.com/
You may have testing by you at a local feed and grain business might send samples in. Contact your local ag.
If I go Melrose feed they send samples in for 12.00
I am going to do research this winter and figure what I need for fertilizer or try. As example I mow my corn stalks down, so many pounds corn stalks equals a percentage of potash back in the soil. I get cow shit from neighbor and there is formulas for that also. Fertilizer so expensive I dont want to just throw my money away. To much fertilizer is bad for environment.
Squash is a nitrogen loving plant, then bell peppers do not like alot of fertilizer, etc etc