I have a dong feng 204 that I use in the garden so these pressures might be a little low for your usage but I put 20 psi in all 4 tires.If you have a lot of hard surface use maybe more pressure is needed.
Idahobob…RonJ has the best reply because you forgot to say if there was a loader on the tractor and if there was anything heavy on the rear. Tire pressure should change accordingly with load.