Any Row Crop farmers....

N/P/K stands for Nitrogen/Potassium/Phosphorous, the three main ingredients in soil fertility. Ph levels indicate acid-to-alkaline conditions and be adjusted by the amounts of lime needed to make the soil close to neutral depending on the type of crop to be grown. I wouldn't use too many chemicals unless absolutely needed, these are food plots and you don't want to put any more chemicals into nature unless you absolutely have to.

Soil samples can be tested thru your local county extension service. If you're intending to just be growing food plots for wildlife, you might want to consider a "no-till" method. That would mean less trips over the field to maintain, less chemicals used, and less ground prep before planting.

When I was a kid on the farm in Iowa growing up, my grandfather used to have food plots and he didn't pour a whole lot into them. He kept it simple and cheap and the wildlife loved it. I would suggest that you visit your local county extension office. They have free information on how to do just what you're looking to do.

You should be able to set your planter to drop seeds closer together for soybeans and milo as opposed to corn. I'd be planting the corn about six inches apart and plant the soybeans about every 1 1/2" apart. Inside the seed bins on the planter at the bottom, you'll see a notched round plate where the seeds are grabbed and dropped thru the planting tube into the ground. You can change these plates to vary the amount of seed dropped in a given length of row, they are called "planter plates" and can be found in many many variations for various planting rates. And you might be able to convert your two row planter into a no-till unit by adding a disc opener in front of the planter shoe and a couple of press wheels behind it to close the furrow as it passes...simple and cheap.