Mormon, as a military man, would easily have filled in the blanks that he did not record. Zemnarihah comes better provisioned with grain than Giddianhi, but a siege is a long-term effort. He therefore counts on supplementing the grain with extensive hunting of wild game in the “wilderness” near the Nephite stronghold (which Mormon mentions) and at least some farming by his army (which Mormon does not). Such farming may be deduced not only from the fact of the siege but from the success of the Nephite raiding parties in harassing the Gadianton farmers. Harrying hunters would have been more difficult, not only because the hunters would be more mobile and moving through more difficult terrain, but also because they would be armed. Farmers are, by definition, less well-armed and less mobile.
This passage provides a few clues about the Nephite stronghold. They could not readily leave to the north, or a siege would have been impossible. It had to be fairly large, since the Nephites could “sally forth” without being immediately attacked by the Gadianton army. This is not, in other words, the typical siege of a walled city by an encircling army. The Nephite area was larger than a city but within which they could still be pinned down enough to create potential supply problems. These problems remained potential, however, since the inside was better provisioned than the outside. No doubt they were supplementing the supplies they had brought with them by growing crops wherever they could protect fields. Pasturing their herds may have been more problematic, given the larger area required for grazing animals (if the herds were composed of grazing animals). Obviously, a requirement was an abundant supply of water.