Some 30 years ago, Farm Journal Magazine did an extensive test of new and nearly bald tires.  Except in extreme mud there was no difference in traction.  If you are no-tilling, you just need something to hold you up, provide stability and reduce compaction.  If you have to match bias duals to radial inner tires, you can run the duals at 8-10 psi provided your axle loads are not excessive.  I've been doing it for lots of years.  Radial duals would obviously be better yet if you can find them used and afford them.  We have a big deer herd here.  I'd much rather run an antler through a worn out tire than a new one.