Find a piece of used high quality hay baler belting (john deere, Vermeer). If the blades strike it they will simply chew a downward facing C shape out of it but it will work fine. Sandwiching it in place with a piece of 1"channel works great to hold it on and prevent stress points that happen with just using bolts. If you weld a plate of steel across the front that will press the material down below the cutting level of the blades and may cause an unclean cut much like trying to run over tall grass with a lawnmower. If you want to weld a piece of 1 1/2" square tubing across the front of the deck to space the belting away from the blades that could help out as well.
Best of luck,
Heath