PART SECOND 



NITROGEN IN FERTILIZERS, DRAINAGE WATERS, ETC. 



247. Kinds of Nitrogen in Fertilizers. Nitrogen is the most 

 costly of the essential plant foods. It has been shown in the first 

 volume that the popular notion regarding the relatively great 

 abundance of nitrogen is erroneous. It forms only a minute part 

 of the matter in and pertaining to the earth's crust. The great 

 mass of nitrogen forming the bulk of the atmosphere is inert 

 and useless in respect of its adaptation to plant food. It is not 

 until it becomes oxidized by combustion, electrical discharges, 

 or the action of certain micro-organisms that it assumes an agri- 

 cultural value. 



2.48. States of Nitrogen. Having described the relation of nitro- 

 gen to the soil in the first volume, it remains the sole province 

 of the present part to study it as aggregated in a form suited to 

 plant food. In this function nitrogen may claim the attention of 

 the analyst in the following forms: 



1. In organic combination in animal or vegetable substances, 

 forming a large class of bodies, of which protein may be taken 

 as the type. Dried blood or cottonseed-meal illustrates this form 

 of combination. 



2. In the form of ammonia or combinations thereof, especially 

 as ammonium sulfate, or as amid nitrogen. 



3. In a more highly oxidized form as nitrous or nitric acid, 

 usually united with a base of which Chile saltpeter may be 

 taken as a type. 



The analyst has often to deal with single forms of nitrogenous 

 -compounds, but in many instances may also find all the typical 

 forms in a single sample. Among the possible cases which may 

 arise, the following are types : 



a. The sample under examination may contain nitrogen in all 

 three forms mentioned above. 



