SOIL EXHAUSTION AND ROTATION IN CROPS. 91 



of agriculture, which have been defined as " extensive " and 

 "intensive." The " extensive " is where land is cheap, and 

 where capital, labor and manure are scarce. There the 

 farmer must go over a great deal of surface, and depend 

 chiefly upon the natural resources of his farm, — getting out 

 of it what he can, " by hook or by crook." "Intensive" 

 agriculture is where the circumstances are such that the 

 farmer uses ai comparatively small quantity of land and a 

 large amount of capital, is able to get fertilizers in abun- 

 dance, and sells his crop quickly and at a good price. He 

 puts a great deal more into the soil and gets a great deal 

 more from it than his "extensive " brother. He works in a 

 more intense way. That is, his labor, instead of being spread 

 over two hundred acres, is concentrated on fifty, and he is 

 able to make his fifty acres more profitable than the other 

 farmer can make his two hundred. In " extensive " agricul- 

 ture we usually have a large quantity of pasture and keep a 

 good many cattle, for we have to depend largely on their ma- 

 nure. We have to sell off a large share of the crops, which 

 remove valuable materials from the soil, and we cannot or do 

 not buy fertilizers to make good the deficiency. In the other 

 case, the farmer can put in as many fertilizers as he chooses 

 to pay for. He is able to buy them, and he finds his profit in 

 using them. In " extensive " agriculture, which is made 

 necessary by circumstances, the farmer must depend largely 

 upon rotation ; he must bring it into successful use. As he 

 succeeds or fails to do this he carries on a paying or a losing 

 business. In "intensive" agriculture the farmer is largely 

 independent of this necessity ; he can rotate or not, very much 

 as he chooses. Rotation is not indispensable to his success. 

 That is, tlie advantages that come from rotation are not so 

 great as the other advantages which the farmer has at com- 

 mand by the use of plenty of money, plenty of fertilizers, by 

 his nearness to market, and high prices. 



Now, I wish to state some of those principles which should 

 govern us in rotation, so far as this depends on what we may 

 call the chemistry of the crop and the soil. So far as the 

 feeding power of the soil is concerned, the special require- 



