"It seems to me," said Percy, "that our farmers are always trying to
find a crop that is adapted to their soil. Down in 'Egypt,' which
covers about one-third of Illinois, the farmers once raised so much
corn that the people from the swampy prairie went down there to buy
corn, and hence the name 'Egypt' became applied to Southern
Illinois. But there came a time when the soil refused to grow such
crops of corn; the farmers then found that wheat was adapted to the
soil. Later the wheat yields decreased until the crop became
unprofitable; and the farmers sought for another crop adapted to a
still more depleted soil. Timothy was selected, and for many years
it proved a profitable crop; but of late years timothy likewise has
decreased in yield until there must be another change; and now whole
sections of 'Egypt' are growing red top as the only profitable crop.
After red top, then what? I don't know, but it looks as though it
would be sprouts and scrub brush, and final land abandonment, a
repetition of the history of these old lands of Virginia and
Maryland."

"Well, can't they grow corn after red top?" asked the Chief.

"Many of them try it many times," replied Percy, "and the yield is
about twenty bushels per acre, whereas the virgin soil easily
produced sixty to eighty bushels."

"And they can't grow wheat as they once did?"

"No, wheat after timothy or red top now yields from five to twelve
bushels per acre, while they once grew twenty to thirty bushels of
wheat per acre year after year.