18 BULLETIN 1070, TJ. S. DEPARTMENT OF AGRICULTURE. 
Certain natural conditions have directed the agriculture on some of 
these lands into a long rotation. The red lands and also the gray, when 
first brought under cultivation, produced good crops of corn and 
small grain. In a few years the corn yield dropped off, so that the 
crop was no longer profitable. Wheat held up to or above the line 
of profitable yield for some time longer. It then went below this 
line, but the losses were not very heavy for some time, and wheat 
continued to be sown, even though not a profitable crop. After a 
few years more, however, the losses became so great on exhausted 
lands that wheat was no longer sown. These lands never have been 
well suited to grazing, and rather than risk time and effort in con- 
Fig. 6. — Early stag? of "resting" land. Broom sedge and briars in foreground, old field pine in distance. 
verting them into hay or pasture they were turned out to grow up, 
first to broom sedge, then bushes, and finally to " old field," or second- 
growth pines (fig. 6). While a few acres of the poorer land on the 
farm may thus be abandoned each year, an approximately equal 
area of new land is cleared up and used, first for corn, then for small 
grain, till in the course of time it also is turned out to grow up. Tiius 
on many of the lands of only moderate natural fertility, a long rota- 
tion has been established, perhaps unconsciously. 
The time required to complete one cycle in the rotation established 
by the farmer and nature working together is variable. It may ba 
20 years or it may be 50. Usually, though, it is a little more than the 
lifetime of a generation of farmers. The grandson clears up and 
farms these old fields abandoned late in the lifetime of the grandsire. 
