12 THE BUSINESS OF DAIRYING 



writer for seven years. The records include the 

 manures and fertilizers applied to each crop and the 

 fertility elements removed in the crops. A record 

 is also shown of the cost of labor and seed, so that it 

 is an easy matter not only to draw a balance with 

 reference to the fertility elements, but to show the 

 cost of producing the crop up to the time of harvest- 

 ing. 



A study of the above account with an acre of 

 ground for a period of five years shows that fertility 

 elements were applied amounting to 156.9 pounds 

 of nitrogen, 244.25 pounds of phosphoric acid, and 

 440.05 pounds of potash. The fertility elements 

 removed amounted to 552.6 pounds of nitrogen, 

 233.16 pounds of phosphoric acid, and 636.22 pounds 

 of potash. Balancing the account by subtracting the 

 amount removed from the amount applied we find 

 that 395.70 pounds more nitrogen has been taken off 

 in crops than has been applied in manures and 

 fertilizers. The question arises, where did this 

 nitrogen come from. It is not very probable that 

 there was this amount of available reserve nitrogen 

 in the soil. It is easily explained, however, when 

 we consider the fact that such crops as crimson 

 clover, Canada field peas and cowpeas, which were 

 grown on this plot, take free nitrogen from the air 

 during growth. It is not surprising, therefore, that 

 more nitrogen is removed in the crops than was ap- 

 plied to the soil. Again, referring to the phosphoric 

 acid, we find that 31.26 pounds more has been 

 applied than removed in the crop, so that an excess 

 remains in the soil. Incaseof the potash I96.i7pounds 



