Picking up on your acre of potatoes: no, you don't need oxen for this. In fact one reason for the importance of potatoes historically is that you can grow them

Picking up on your acre of potatoes: no, you don't need oxen for this. In fact one reason for the importance of potatoes historically is that you can grow them on marginal land with only hand labour. There are various techniques such as the lazybeds used by displaced Highlanders in Scotland, but they don't need oxen. In fact oxen had their heyday before the iron ploughshare, as you needed a team to pull the older wooden plough, and the plough was used for planting grain. Of course these days it is also used for planting potatoes on rich land, but that's not essential.