FACTORS OF AGRICULTURAL PRODUCTION 159 



Another illustration of the substitution of more productive for 

 less productive crops is the general invasion of the cattle ranges 

 of the Far West by settlers who are bringing the land under 

 the plow. As the corn belt has pushed the wheat belt farther 

 west, so the wheat belt has pushed the cattle belt farther west. 

 So long as there was unoccupied range country into which the 

 ranchmen could migrate, the ranches merely moved on ahead 

 of the wheat belt. But when all the range country was once 

 occupied, further migration of the wheat belt westward meant 

 the extinction or partial extinction of the range-cattle industry. 

 This is the tendency which has been showing itself in recent 

 years. Even within the range country a similar process has 

 been going on in the crowding out of the cattle by the sheep, 

 the latter being better adapted to picking a living on those 

 lean pastures. 



With these migrations of the different " belts " of agricultural 

 production there has probably been no material change in the 

 relative acreage devoted to the different products for the supply 

 of the markets of the whole commercial world. It is not possible 

 to measure the different acreages accurately, but until the commer- 

 cial world changes its habits of consumption it will continue to 

 demand the different products in about the same proportion. If 

 we could imagine the whole available land of the globe as occu- 

 pied and brought under cultivation, and that such terms as " old 

 countries " and " new countries " had lost their meaning, it 

 would not then be possible to imagine these different belts of 

 production as pushing one another farther and farther toward 

 the new and- cheaper lands. If, then, the consumers of the 

 world were to continue with their present habits of consumption 

 unchanged, further substitution of heavier-yielding crops for the 

 lighter-yielding crops would scarcely be possible. This would 

 be made possible only by a change in consumption of less 

 meat and more milk and eggs, the substitution of corn for wheat 



