EXAMINATION OF FERTILIZING MATERIALS, 

 FERTILIZERS, AND MANURE 



PART FIRST 



DEFINITIONS, SAMPLING AND PRELIMINARY TREATMENT 



1. Introduction. The principal plant foods occurring in soils 

 are named and the methods of estimating them described in the 

 first volume. As fertilizers are classed those materials which 

 are added to soils to supply deficiencies in plant foods or to render 

 more available the stores already present. There is little difference 

 between the terms fertilizer and manure. In common language 

 the former is applied to materials prepared for the fanner by 

 the manufacturer or mixer, while the latter is applied to those 

 accumulated about the stables or made elsewhere on the farm. 

 Thus it is common to speak of a barn-yard or stall manure and of 

 a commercial fertilizer. This distinction is more nominal than 

 real. If a choice is to be made between terms, manure is pref- 

 erable. The term fertilization, moreover, is applied biologically 

 to the effective congress of the male and female elements of the 

 egg, and thus confusion may arise by the application of that term 

 to any process of manuring. 



In harmony with the common practice in this country, however, 

 the words will be used in this volume in the sense indicated above. 



One of the objects of the analysis of soils is to determine the 

 character of the fertilizer which should be added to a field in 

 order to secure its maximum fertility. 



One purpose of _the present manual is to determine the fitness 

 of offered fertilizing material to supply the deficiencies which may 

 be revealed by a proper study of the needs of the soil. 



2. Occurrence of Fertilizers in Nature. In the succession of 

 geological epochs which has marked the natural history of the 

 earth there have been brought together in deposits of greater or 

 less magnitude the stores of plant food unused by growing crops 



