1906.] PUBLIC DOCUMENT — No. 33. 21 



It will be noticed that the yield on the three no-nitrogen 

 plots (4,7,9) is much below the yield obtained on any of the 

 plots where fertilizers supplying nitrogen were used. There 

 was a fair proportion of peas in the crop, but, in spite of the 

 fact that i)eas are usually al)le to take a considerable pro- 

 portion of their nitrogen from the air, it is very clear that it 

 will be unwise, in the case of a mixed crop including a legume 

 and a non-legume, to depend to any great extent upon this 

 atmospheric source of supply. The average yield of the 

 three no-nitrogen plots was at the rate of 4,350 pounds of 

 hay per acre. The average yield of the nitrogen plots was 

 at the rate of 6,400 pounds per acre. Here is a difference 

 of a little more than 1 ton per acre, which is far more than 

 sufficient to cover the cost, $7.85, of the amounts in wliich 

 such fertilizer was used. It will be noticed, further, that 

 the yield on the })lot to which barnyard manure is annually 

 applied is nmch below that on even the poorest plot to which 

 a nitrogen fertilizer was applied. The manure in question 

 was put on at the time of preparing the soil in the spring, 

 and evidently the nitrogen it contained did not become in 

 large degree available in season to benefit crops making 

 their growth so early in the growing season as oats and 

 peas. The average yields of this year on the several fer- 

 tilizers are shown in the following table : — 



Fertilizers used. 



Hay 

 (Pounds). 



Average of the no-nitrogen plots (4, 7,9), . 

 Average of the nitrate of soda plots (1, 2), . 

 Average of the dried-blood plots (3, 10) , 

 Average of tlie sulfate of ammonia plots (5, (!, 8), 



4,350 

 6,950 

 6,600 

 6,383 



As the result of experiments previous to this year, it has 

 been found that the materials furnishing nitrogen have pro- 

 duced crops in the following relative amounts : — 



Per Cent. 



Nitrate of soda, 100.00 



Barnyard manure, . 

 Dried blood, . 

 Sulfate of ammonia, 

 No nitrogen, . 



96.02 

 90.83 

 88.62 

 72.11 



