You are asking a question with an almost infinite set of possible responses. Here is my suggestion. This is opinion based on my experience.

I totally agree with you that corn in most areas MN needs black soil to plant into in the spring.  This is ESPECIALLY true in your rotation where you are always planting corn into wheat stubble. Going into wheat stubble with corn it is useful to clear that residue out of the way in late summer or early fall after wheat harvest but ahead of corn and bean harvest so you know it is done.

I really do NOT like the idea of putting down dry fertilizer with your 16R30 JD 1770NT planter for several reasons.  #1 is that the least expensive way to higher corn yield is timely planting. There are many things that can go wrong with dry fertilizer systems. Many of my customers have gone back to just putting seed in the planter and keeping that planter rolling until everything is done. That is near impossible to do when you are nursing a dry fertilizer air cart system attached to the planter.

Another reason I don't like air applying dry fertilizer on the planter is that I look at a planter as a precision tool. Dry fertilizer dust in an air application system gets into and on everything and you know how corrosive that fertilizer is. You are taking the most important tool on the farm (the planter) including many electrical connections, and likely turning it into a rust bucket.

If you are talking about 8 on 16 you must have rtk guidance. One economical system in your area would be to use a rigid 8R30 strip till bar on the back of your new fertilizer cart's 3 point. We sell a 20 ft/8R30 HD 3-point toolbar with gage wheels for $4250. Or go to a Moore-Built or similar bar if you need a folding bar. At 8 mph + this generally has no trouble staying aheaqd of a 16 row planter even with all done in the spring in flat terrain with rtk. On this bar I would suggest 8 of our high speed Pluribus strip till units with dry fert tubes.

With this setup you could go into your wheat stubble in late summer or early fall and clear and work black strips while incorporating dry P, K and micros as required.

Come back again in early spring over these same fall made strips in wheat stubble to freshen the strips. Depending on how far ahead of planting you are in the spring you could use either dry urea, liquid 28 or 32% or both. If you are a day os so ahead of the planter you can band the 28% as I do (32 gal) as my total N and plant the next day.

For your soybeans into corn stalks I would again run between the cornstalks after corn harvest to blacken a strip for 30" beans, maybe applying a little dry P. With beans being planted later in the spring than corn, just row cleaners on the planter along with Curvetine closing wheels would probably be all you need to plant into these stale strips in the spring. If you wish and had time you could run over the strips again in the spring ahead of beans also. You may want to try just spring strips into bean stubble which you can do with our no-shank/all coulter Pluribus. Depends on your soils etc.

Beans just explode out of the ground in a cleared black strip between corn stalks. Some folks in MN have good success running a roller behind the planter over beans planted between stalks. The roller pushes down rocks, levels the surface for harvest and also kinks the between-row cornstalks (but leaves them attached and not blowing) for faster breakdown laying flat on the ground...

Then drill your wheat into this nice flat surface after bean harvest....

This system accomplishes your goals with fewer passes and less equipment. And when it is time to plant you put seed in the planter and plant!

jmho.

Jim at Dawn