No. 6. DEPARTMENT OF AGRICULTURE. 523 



nitrogen is calculated. Another portion of water-insoluble ma- 

 terial* is treated with alkaline potassium permanganate, which 

 attacks the nitrogenous organic substances present, and converts the 

 more active portion into ammonia, which is distilled off, determined 

 and its nitrogen calculated as ^^active insoluble nitrogen." The ''inac- 

 tive insoluble nitrogen" is then computed by subtracting the active in- 

 soluble from the total insoluble nitrogen. The term "available nitro- 

 gen" as used in this report, is the sum of the water-soluble and the ac- 

 tive insoluble nitrogen. It is equivalent to the total nitrogen less the 

 inactive insoluble nitrogen. In high grade organic nitrogenous mater- 

 ials, among which, from its behavior with this treatment, must be 

 included horn meal, the percentage of inactive nitrogen in the insolu- 

 ble nitrogen is usually under 40 per cent.; and the ratio of inactive 

 to active insoluble nitrogen in such materials is usually less than 

 60 : 100. On the other hand, in the case of low-grade nitrogenous ma- 

 terials, the proportions of inactive nitrogen are much higher. The 

 separations effected by these methods are therefore of great value 

 in distinguishing whether the insoluble nitrogen is derived from high 

 grade materials, or from low grade substances such as garbage tank- 

 age, peat, mora meal, unacidulated hair, leather, etc. There is, 

 however, one fertilizer ingredient rapidly coming into use, whose 

 presence may lead to erroneous conclusion, if judgment is based 

 solely upon the facts ascertained by the foregoing method, namely, 

 cyanamid. This substance contains from 13 to 16.5 per cent, of ni- 

 trogen, of which 12 to 14.7 per cent, is soluble in water, by the mode 

 of treatment used in the alkaline permanganate method ; and, of the 

 1.0 to 1.7 per cent, of water-insoluble nitrogen, less than one-fifth is 

 active; so that the ratio of inactive to insoluble nitrogen is about 

 80 : 100. Owing to its tendency to reduce the availability of the 

 phosphoric acid in acid phosphate mixtures, limited quantities only 

 of this ingredient can be used advantageously in mixed fertilizers. 

 Nevertheless, in cases where low grade sources of nitrogen are in- 

 dicated by the foregoing method, it would be needful to determine, 

 by supplementary tests, whether or not cyanamid may be present to 

 account for the undue proportion of inactive, insoluble nitrogen, 

 before concluding that such excess of inactive nitrogenous material 

 is attributable to low-grade nitrogenous constituents. It is desir- 

 able to keep in mind at this point the fact also that certain widely 

 used low-grade nitrogenous substances, such as garbage, tankage, 

 peat and mora meal, are not included in the list of substances whose 

 presence requires specific declaration under Section 4 of the Fertilizer 

 act. 5) Chlorin— this determination is made to afford a basis for 

 estimating the proportion of the potash that is present as chlorid 



•This determination has been omitted in all cases where the Insoluble nitrogen Is only .2 per 

 cent, or less. 



