458 MISCELLANEOUS FARM SUBJECTS 



in their action, may be regarded as standard in the sense that they 

 can be depended upon to furnish practically the same amount and 

 form of the constituents wherever secured. For example, a ton of 

 nitrate of soda or boneblack superphosphate (dissolved boneblack) 

 will on the average furnish 320 pounds of nitrogen or of phosphoric 

 acid, the nitrogen all in the form of a nitrate and the phosphoric acid, 

 practically all soluble. Hence nitrate of soda, sulphate of am- 

 monia, dried blood, and superphosphates and potash salts are stand- 

 ard products, because they can be depended upon, both in respect to 

 the content and form of their constituents. 



On the other hand, the low-grade or nonstandard materials are 

 not merely poorer in their total content of plant-food constituents, 

 but also contain forms of the latter which are very variable in their 

 availability. No exact value can be assigned, for instance, to ground 

 bone, since this is a product quite variable in composition and in 

 the availability of its nitrogen and .phosphoric acid, owing to its 

 origin, its mechanical condition, and the method of treatment to 

 which it was subjected. Because of the differences thus introduced 

 different samples of bone cannot be expected to yield the same re- 

 sults, even though they be used under the same conditions of soil and 

 climate. The same applies even more strongly to the various kinds 

 of tankage. We note here wide differences in the proportion of ni- 

 trogen and of phosphoric acid, and differences as great or greater in 

 the availability of these constituents. They can not be expected, 

 therefore, to yield constant and uniform results under any given 

 climatic conditions in the same degree characteristic of the standard 

 high-grade products. 



Mixed Fertilizers. The tendency of the fertilizer trade in this 

 country has been toward the manufacture and sale of mixed fertil- 

 izers containing moderate quantities of two or three of the essential 

 fertilizer ingredients. The various brands of fertilizers thus com- 

 pounded are sold under special names indicating the purpose for 

 which the fertilizer is supposed to be especially adapted. The names 

 sometimes also give a clue to the origin of the fertilizer, but oftener 

 do not. Ammoniated superphosphates manufactured and sold by 

 eastern fertilizer manufacturers, are prepared from acid phosphates 

 (dissolved bone, superphosphate) to which some nitrogenous fer- 

 tilizer material has been added. As it is difficult to prove the origin 

 of organic nitrogen compounds by chemical tests, it is but natural 

 that unscrupulous manufacturers should seize this opportunity to 

 adulterate superphosphates with nitrogenous compounds of inferior 

 fertilizer value, like leather scraps, horn shavings, hoof meal, etc. 



When the farmer studies the apparent needs of his land and 

 understands the subject of fertilization of crops he will prefer to 

 buy special fertilizing materials of definite, known composition, in 

 proportions best adapted for his purposes, rather than use mixed fer- 

 tilizers, the different components of which he does not know, and 

 parts of which may be of no particular value. The mixed fer- 

 tilizers came into existence in response to a demand for this kind 

 of goods, but it is believed that as farmers learn the principles gov- 



