Producing Silage without using Bunkers
Some producers have been successful storing silage in above ground piles. The secret to any storage method is to minimize surface area exposed to air, and a tight (dense) pack to eliminate as much air in the stack as possible. The larger and deeper the stack the better. We usually call it a drive-over stack because we use a tractor to pack the stack to remove as many voids as possible. Smaller packages produce more surface area per ton of silage and are harder to pack. A few people have made baleage successfully, but it takes a good baler and not all round balers will do the job. Some silage producers use a big plastic tube. But it requires specialized equipment to stuff and pack the tubes.
See this University of Florida publication on silage making.
Pen State Publication