On 30 Jan, 14:18, "Mike Lyle" wrote:
This whole question arises because British gardening and farming
books, no doubt sometimes uncritically copying one another, always
used to say "potatoes are a good clearing crop". This phrase entered
people's consciousness _without_ the rest of the chapter. It doesn't
mean potatoes are good at clearing: it means they're good crop to grow
if _you're_ clearing a plot.

I agree, although I have also understood that they are good at
breaking the disease cycle of other (native) crops. Being an alien
species they have different pests, and can thus help prevent year-on-
year accumulation of pests of whatever used to be grown. Part of one
of the 19th century crop rotations.

There is no doubt, though, that the cultivation of the potatoes is
what does the actual work.