NITROGENOUS FERTILIZERS 



167 



dergo ammonification and nitrification in the soil. Some 

 of them decompose much more readily than others. 



In order to ascertain the relative degree of availability of 

 the nitrogenous fertilizers, experiments have been conducted 

 by numerous investigators in which they have used one of 

 these fertilizers on one or more plats of land, or in one or more 

 vessels of soil, and other nitrogenous fertilizers in a similar 

 way. It is, of course, always necessary that there shall be 

 an abundance of all the other plant-food materials. These 

 experiments were repeated for several years with different 

 crops, at the end of which time a comparison was made of the 

 yields of the crops on the soil treated with the different fer- 

 tilizers. In Table 36 the results of some of these experiments 

 are stated, with the yields obtained with nitrate of soda 

 taken as 100 in each case. 



Table 36. — Relative Effectiveness of Nitrogenous Ferti- 



Nitrogen Carriers 



Nitrate of soda . . 

 Sulfate of ammonia 

 Dried blood . . . 

 Bone meal 

 Stable manure . . 

 Tankage .... 

 Horn-and-hoof meal 

 Linseed meal . . 

 Cottonseed meal 

 Castor pomace . 

 Wool waste . . . 

 Leather meal . . 

 Dry ground fish 



Voorhees 



AND 

 LlPMAN 



100 

 70 

 64 



53 



While these experiments are helpful in giving an idea 

 of the relative values of these fertilizers, they do not necessa- 



