I think you should call the extension agent for that county. He would be able to give you more specific answers. I'm sure he will recommend a soil test. He will also be able to interpret it for you when you get it back. But it will probably take two weeks.<img src=icon_smile_blackeye.gif border=0 align=middle> You don't really have time. Next year....
Ask him about the chicken/pig manure. Something rings a bell about them being high in nitrogen. The things you want to plant fix their own nitrogen from the air(be sure to inoculate with the right inoculant!). Add in the 13-13-13, and I think you might have too much. It would at least run off into the local stream, and may burn your plants. The manure on your plot is already runoff from the areas above. The existing levels will be on the soil test...
The soil test will tell you much more than pH, which you will have a lot of trouble changing if necessary. But it will give you a better idea of what will effectively grow there. That may be clover/chickory/peas!
I'd still get in there and plant it.
Another idea would be to plant wheat or rye there for this fall, till it under in the spring(when you have the soil test results), and then give the clover a full growing season to establish.
Good luck, and remember that the local farmers know an aweful lot, too.
-ost