440 ~ STATE BOARD OF AGRICULTURE, 



200 lbs. 10% Acid Phosphate costs 



100 lbs. 20% Acid Phosphate costs 



Saving per acre 



200 lbs. 10% Acid Phosphate costs 



125 lbs. 16% Acid Phosphate-*costs 



Saving per acre |1 . 21 



Exactly the same amount of available phosphoric acid is contained in 

 100 lbs. of 20% acid phosphate or 125 lbs. of 16% acid phosphate as 

 in 200 lbs. of 10% acid phosphate and the saving in one case is |1.63 

 and in the other |1.21. Still some farmers continue to use 10% acid 

 phosphate because it is cheaper per ton. 



In these times when labor is scarce and very expensive the farmers 

 should endeavor to produce the maximum amount per acre. The judic- 

 ious use of fertilizers will help toward this end and careful buying will 

 have much to do with the amount of profit derived from the use of 

 fertilizers. 



EXPLANATION OF TABLES. 



The results of analysis shown in the following tables are arranged 

 by manufacturers, in alphabetical order. Those found below guarantee 

 are printed in bold-face type. 



Nitrogen. It will be noted that the results under this heading are 

 divided into four columns. The column headed "As Soluble" shows the 

 amount of nitrogen that is soluble in water. This would include all 

 nitrogen present as nitrate of soda, sulfate of ammonia, cyanimid, etc. 

 This portion of the nitrogen is considered to be immediately available. 



The second and tliird columns together represent the nitrogen that 

 is insoluble in water. This insoluble niti'ogen is sepai'ated into "active" 

 and "inactive" nitrogen depending upon its reaction with an alkaline 

 solution of potassium permanganate. When the amount shown "as ac- 

 tive insoluble organic" is greater than that shown "as inactive insoluble 

 organic" the whole insoluble nitrogen is considered to be of good qual- 

 ity. In other words, it has been derived from some high-grade material 

 possessing a high rate of availability or the material used has been 

 treated in such manner as to render it largely available. If, on the 

 other hand, the amount of nitrogen shown in the "inactive" column is 

 greater than that shown in the "active" column then the insoluble 

 nitrogen is considered to be low grade with a low rate of availability. 

 U'^hen the insoluble nitrogen constitutes a small percentage of the total, 

 its rate of availability would, of course, be of small consequence. But, 

 where the "insoluble nitrogen" constitutes a considerable j^ortiou of the 

 total, as is very often the case, then, its rate of availability is an im- 

 l»ortaut factor. 



Since nitrogen is, by far, the most expensive plant-food ingredient in 

 fertilizers, more attention should be given to tlie results printed in the 

 following pages under this heading and when purchasing nitrogenous 

 fertilizers preference should be given those companies that show the 



