I always preferred carrying my extras loose in the front pockets with the shell loops. They're easier to access that way than they would be from a belt. I'd be afraid of losing a few out of a belt. And a belt could chafe-either around the waist or worn as a bandoleer-during all that walking. Besides, you'll have plenty of time to reload after shooting your two or three in the gun.
It's easy to load the loops full, then a half box in each pocket, plus what's in the gun. Do you need more than 37 or 38 rounds in a morning? You can restock back at the truck during lunch.