35 



The average cost from all sources, lime-fertile excepted, was 63.6 cents. 

 The degree of fineness (mechanical condition) of the ground limestones was 

 about the same as in 1919 and, on the whole, was quite satisfactory. 



EXPLANATION OF TABLES OF ANALYSES. 



In the tables of analyses the products have been grouped according to the 

 elements of plant food furnished and in the following order: complete ferti- 

 lizers, ammoniated superphosphates, fertilizers for private use, fertilizers 

 supplying phosphoric acid and potash (including wood ashes), ground bone 

 and tankage, dry ground fish, lime compounds, nitrogen compounds, phos- 

 phoric acid compounds, and potash compounds. All analyses have been 

 alphabetically arranged according to manufacturer as well as brand name. 

 The columns in the tables of analyses will be found self-explanatory with 

 possibly two exceptions : — 



First, " Relative Cash Cost of Like Amounts of Nitrogen, Phosphoric 

 Acid and Potash in Unmixed Materials." This represents the comparative 

 commercial valuation of the fertilizer. It is figured from the analysis by the 

 use of the table of trade values. 



Second, a change has been made this season in the manner of reporting 

 the several forms of nitrogen. In place of the columns " Water Soluble " and 

 "Water Insoluble," which have been used in the past, one column headed 

 "Organic Nitrogen" has been substituted. The quality of the water insoluble 

 portion of this organic nitrogen is indicated in an adjoining column by the 

 word "good," "passed" or "inferior." The interpretation of this classifica- 

 tion is as follows: " good " indicates a water insoluble organic nitrogen activ- 

 ity (by the alkaline permanganate method) of 55 or over; " passed " indicates 

 an activity of between 50 and 55; and "inferior" indicates an activity of 

 less than 50. 



Footnotes accompanying the tables of analyses of mixed fertilizers indicate 

 the form of potash present. The absence of footnote reference indicates that 

 the potash was present in the form of muriate, or at least that enough chlorine 

 was present to unite with all of the potash found. 



