You usually did not get good cycling with granaries available with D&D tech level.Farms arent necessarily nature killing, the Roman Farm included an irrigated garden, willow plantation, olive orchard, meadow, grain land, forest trees, vineyard and an acorn woodlands and encouraged nymphs to visit. A druid who sees people as part of nature and farming as a way to boost productivity of the surrounding lands should be happy to help.
Even practices like Swidden farming that use Fire in some tropical ‘jungle’ areas help forest regeneration and nutrient cycling.
properly stored grain in a granary could last up to four years with good cycling. Its also important to remember that hard bread and fermented grains (ie Beer) were important rations as beer in particular allowed Grain to be stored indefinately.
However I am confused by your reference to Nile shipping - how did that help the Romans get grain from Spain or when they went north into Europe?
Converting grain into bread and beer increases its volume and thus requires more storage space. And the more space you need the harder to keep it vermin free.
The main food source for Rome was Egypt, not Spain or Europe. Partly because Egypt very fertile and partly because shipping was easy as all farms were near a major river with easy sea access.
Last edited: