1910.] 



PUBLIC DOCUMENT — No. 31. 



37 



I, The experiments on Field A, which have for their object 

 the determination of the relative value, as sources of nitrogen, of 

 some of the leading materials which may be used to furnish that 

 element, have been continued. These experiments were begun 

 in 1890. The crops grown in order of their succession have 

 been : oats, rye, soy beans, oats, soy beans, oats, soy beans, oats, 

 oats, clover, potatoes, soy beans, potatoes, soy beans, potatoes, 

 oats and peas, ,corn and clover for the last two years. These two 

 crops have been considerably mixed with grass. The best crop 

 of the year was produced where dried blood was used as a source 

 of nitrogen, but the crop produced upon nitrate of soda was 

 practically the same. On the basis of 100 for nitrate of soda, 

 the relative standing of the diiferent nitrogen fertilizers and 

 the no-nitrogen plots (total yield) was as follows: — 



Per Cent. 



The relative standing of the different materials for the twenty 

 years during which the experiments have continued is as fol- 

 lows : — 



Per Cent. 

 100.00 



94.05 



Nitrate of soda, . 

 Barnyard manure, 

 Dried blood, . 

 Sulfate of ammonia, 

 No nitrogen, 



92.34 

 80.47 

 70.99 



On the basis of increase in crop as compared with the no- 

 nitrogen plots the average of the twenty years shows the fol- 



lowing relative standing : — 



Nitrate of soda, . 

 Barnyard manure, 

 Dried blood, . 

 Sulfate of ammonia, 



Per Cent. 



100.00 

 79.51 

 73.62 

 53.36 



It will be seen that the nitrate of soda has given a much 

 larger average increase in crop than any of the other materials. 



