AGRICULTURE AND RURAL ECONOMY. 



563 



acid and 75 pounds of potash per acre, was taken as a basis, 

 and nitrogen added in different proportions and combina- 

 tions. The amounts of phosphoric acid and potash were about 

 such as occur in a crop of 50 to 56 bushels of corn with 

 stover. The nitrogen was given in successive portions of 

 24, 48, and 72 pounds, or one third, two thirds, and the full 

 amount in the same crop. Duplicate trials were made with 

 nitrogen, in nitrate of soda, in sulphate of ammonia, in dried 

 blood, in a mixture of all three, and in Peruvian guano. Es- 

 timating the fertilizers at market prices, plus $5 per ton for 

 freight and applying, and a bushel of corn with its stover 

 to contain 1^- pounds of nitrogen, and to be worth 80 cents, 

 the effects of the nitrogenous fertilizers in these and in the 

 previous experiments may be summarized as follows: 



The nitrogenous fertilizers gave paying returns in nine 

 trials out of fifty-three. The loss was larger or smaller in 

 proportion as more or less nitrogen was used. 



As regards the action of the different compounds of nitro- 

 gen, the Peruvian guano brought the largest increase; the 

 mixture of nitrate of soda, sulphate of ammonia, and dried 

 blood next; then followed in order nitrate of soda, sulphate 

 of ammonia, and dried blood, which was worst of all. The 

 Peruvian guano appears at a somewhat unfair advantage, 

 however, because it had rather more phosphoric acid than the 

 mixtures in which other forms of nitrogen were used. On 

 the whole, the results of these field trials by farmers imply 

 that superphosphate and potash salts, or these with Peruvian 

 guano, are as profitable fertilizers as farmers can buy for corn. 



VI. THE NUTRITION OF DOMESTIC ANIMALS. 



Investigations on the feeding of domestic animals during 

 the year has been continued with unabated activity, but has 



