158 PRINCIPLES OF RURAL ECONOMICS 



crops instead of growing it exclusively. In either case the grow- 

 ing scarcity of land and the increasing supply of labor have 

 brought about a certain amount of substitution of heavy-yielding 

 for light-yielding crops. 



This substitution of heavy-yielding for light-yielding crops 

 presents some exceedingly complicated economic problems. As 

 suggested above, one factor in the movement of the wheat belt 

 westward was that of transportation, though the existence of 

 cheap land and opportunities for extensive cultivation were the 

 most important ones. The factor of transportation is also im- 

 portant in the cultivation of the still heavier-yielding but less 

 transportable market-garden crops in the neighborhood of large 

 cities. The general rule is that the products which are more 

 bulky or perishable or otherwise difficult of transportation must 

 be produced near the place of consumption, and those which 

 are less bulky or perishable or are otherwise easier of trans- 

 portation may be grown farther from places of consumption. 

 This, however, is a means of economizing the labor of trans- 

 portation rather than of economizing land. Moreover, this form 

 of territorial division of labor is economical only when there 

 are densely settled and sparsely settled regions of about equal 

 fertility. As the whole country becomes more densely populated 

 it will be found economical to give the land over more and more 

 to these bulky and perishable as well as to the heavy-yielding 

 crops, and to depend upon newer and more sparsely settled 

 countries for our supplies of wheat and similar light-yielding as 

 well as easily transportable crops, provided we have something 

 to send to these new countries in exchange. It happens that 

 wheat and beef are products well adapted to frontier conditions. 

 Accordingly, we need not be surprised to find in the United 

 States that, as the 'country settles, these two products will 

 dwindle and other more profitable crops take their place. It is 

 really a sign of advancement and not of deterioration. 



