Il8 PRINCIPLES OF RURAL ECONOMICS 



the mine depends mainly upon the depth and richness of the 

 deposit rather than upon the superficial area. In agriculture, 

 however, no matter how deep the soil or how rich the deposit 

 of plant food in a given area may be, there is a limit to the 

 number of plants which can grow on that area, and therefore 

 the product of that area does not depend exclusively upon the 

 depth and richness of the deposit ; it depends quite as much upon 

 the size of the area, quite as much upon the room which it 

 affords to the plants as upon the food which it provides for them. 



A soil of immeasurable depth and richness will produce only 

 a very limited crop of wheat per acre, say a hundred bushels, 

 but a mineral deposit of immeasurable depth and riches would 

 yield a quantity of mineral per acre limited only by the number 

 of laborers and machines that could find room to work. Even 

 if the greatest conceivable skill were applied to the cultivation 

 of the soil, it would still take vast areas of land to produce wheat 

 enough to supply any modern nation with bread. A similar 

 statement would hold true of any of the other great farm crops. 

 That is why the question of land is of such vital importance to 

 every agricultural nation. 



Law of diminishing returns. Even assuming it to be possible 

 to make one acre produce a hundred bushels of wheat, it by no 

 means follows that it would be economical to try to do so. In 

 fact, it most certainly would not be economical, for the reason 

 that it would require such a quantity of labor and care in the prep- 

 aration of the soil, in the selection of the seed, and in the nurture 

 of the plants, as to amount to a great waste of time and energy, 

 a waste so great as to overbalance the economy of land. It would 

 require much less labor to produce a hundred bushels on two 

 acres than on one, probably less on three acres than on one, and 

 quite possibly less on four than on one. This being the case, 

 each farmer will find it to his advantage to spread his cultivation 

 over more acres rather than to try to make each acre produce 





