I don't really know about corn stalks, but our area agronomist did some work in the area of burning wheat straw, which used to be the normal practice when planting doublecrop soybeans.  His work showed that even a relatively poor soybean crop will return more to the field then the wheat straw contained.   If the soybeans were good enough to establish decent nodulation there was absolutely no comparison. 

If I have not forgotten all of my crop science, less then half of the residue from a corn plant is above ground anyway.