"Loading" the tractor's rear tires with liquid will increase traction in a cost effective way.
Adding wheel weights will also increase traction, though iron weights are much more costly.
MORE ON WHEEL/TIRE
BALLAST:
www.orangetractortalks.com
Consider routinely carrying around a Three Point Hitch implement as FEL counterbalance and additional wheel ballast if you need yet more traction. A considerable amount of the implement weight is transferred to the tractor wheels, both front and rear, through the Three Point Hitch.
Before your next tractor purchase consider this: Within subcompact and compact tractor categories, a significant tractor capability increase requires a bare tractor weight increase of 50%. It takes a 100% increase in bare tractor weight to elicit MY-OH-MY!