MANURES AND FERTILIZERS. 133 



in the case of tankage, it is best when applied with 

 manure, because of its lack of organic matter. It need 

 not be applied in the fall, for if broadcasted and har- 

 rowed in when the ground is being prepared in the early 

 spring, it will become available for the crop by the 

 time the plants are set. 



Other Nitrogenous Substances. In addition to these 

 flesh preparations, there are others known as azontine, 

 ammonite, etc. These are simply preparations of dried 

 meat, but are of higher grade than tankage and are 

 more uniform in composition. They can be classified 

 with dried blood and similarly handled. 



NITROGEN SALTS. 



Beside the organic nitrogen supplies, both animal 

 and vegetable, described in the previous pages, an 

 entirely different class exists, known as "salts." These 

 salts are crystallized salts of nitric acid or ammonia. 

 They are perfectly soluble in water, and the nitrogen is 

 in an immediately available condition. They contain 

 no organic matter of any kind, but are practically pure 

 chemicals. They are held in very high esteem for all 

 crops, and are of special value for tobacco, but to obtain 

 the best results they should be used on soils naturally 

 rich in organic matter, or made so artificially by the use 

 of manure, castor pomace, muck, or compost. 



There is nothing gained in applying these chemicals 

 much in advance of the crop, for they are perfectly 

 available as plant food whenever applied. In this they 

 differ from all the fertilizing materials previously con- 

 sidered. The nitrogen in all animal and vegetable mat- 

 ter is partly inert and cannot be set free until such 

 matter is disintegrated by fermentation. All these or- 

 ganic matters, therefore, require time, in which this 

 fermentation may go on, before the nitrogen contained 

 in them can be utilized by the plant. But experience 



