The idea is just great: a cellar! not just another silo!
I would prefer instead of the ladders, a ramp for tractors, and a higher ceiling. maybe on the upper level a higher ceiling for stacking bales, and in the cellar some kind of 'futterlager' with heaps for hay/grass, silage, straw, maybe mixed food too.
Looks very cool too, the old mortar/brickwork and all.
Also, maybe a version with only the underground area that could ba positioned under some already existant building on the farm, somewhere on the cow husbandry area..On the surface, only the access ramp/tunnel.