I Blame Communism
Banned
Yes, but the purpose of setting up these massive corn and wheat plantations is to provide food for proper Englishmen. The English never ate potatoes the way the Irish did, so these colonies would exist to work the Irish to death while exporting wheat to England.
Impossible before the railway, the steamship, and modern understanding of how to preserve food. The reason there was an agricultural price-crash in the 1870s is that it was now possible for an Englishman to eat food grown in Nebraska or Argentina or Ukraine. Previously, Englishmen ate the food grown in England, by themselves: that's how pre-industrial society worked.