THE YOUNG FARMER 



to distinguish between the natural fertility 

 of the soil and the condition of the soil. A 

 further example will help to illustrate this 

 point. At the Rothamsted Station a cer- 

 tain type of soil has for over 60 years pro- 

 duced annually about 12 bushels of wheat 

 an acre without fertilizer, while with a 

 complete fertilizer the same type has pro- 

 duced 30 or more bushels. The 12 bushels 

 may be said to represent the natural fer- 

 tility of the soil, while the additional 18 

 bushels may be said to represent the condi- 

 tion of the soil due to fertilizers or to other 

 conditions. On the other hand, the natural 

 condition of some other soil type might be 

 only eight bushels, or still another type 

 might be 16 bushels. 



This principle is of considerable practi- 

 cal importance, especially in the eastern 

 third of the United States. Generally speak- 

 ing, clay and silt soils have a greater natural 

 fertility than sandy soils; limestone soils 

 than those that are deficient in lime. Thus 

 soils that naturally grow chestnut trees, indi- 

 cating a low lime content, have a tendency 



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