So my thinking is to some extent as described, but also the seeding rates that I may end up with.
each growing turnip will produce dozens of seeds so if they where to grow on their own they would be way too heavy and be stunted. As for the peas, the peas produce a larger seed that many birds will eat if they can find them and they will germinate much better if actual covered with soil. The clover is an annual and it may re-seed to some extent. So what may grow back on it's own may be very different seeding rate wise vs what I planted originally. Also the deer here prefer the clover and the peas and the turnips are more of an insurance policy as the deer here don't care for them much at all unless they have no other choices....and that is important when you are focused on hunting season attraction vs survival food for the deer. It would be like a little bitty burger on a huge bun!
To the other portion....putting that organic matter back into the soil is good for it. I will probably have to terminate some of the plants, but most will more than likely be dead by mid summer naturally...or at least not be of much interest to the deer. I will mow or spray to terminate and then use a tiller to work that matter into the soil and then plant my larger seed with a row planter and broadcast the rest and pack. If the plot surprises me and I have a lot higher clover content, I can always just leave it alone as well. Time will tell.
You are correct that to some extent the plot will "reseed" itself, but the ratios and the like that would result will lead to less than desirable results. That is simply the cycle of an annual food plot. If I do what I plan on I won't plant ANY turnip seed because I am pretty certain I will have enough seed already in the soil to do what I need. Hopefully the seeds will also help the quail and the like also....it's hard to tell. I have not let an annual plot go like this before so I will see what works and what doesn't.... I have 3 plots like this so I may try different things in sections of them or in one plot and not the others. Hard to say...