New York Agricultural Experiment Station". 653 



and high-grade brands of fertilizers is considerably greater now than 

 then, while the reverse is true of the lower grades. The figures for 

 1902 are as follows: Low-grade 25 per ct.; medium grade, 34 per ct.; 

 medium high-grade, 24 per ct.; high-grade, 17 per ct. It is thus seen 

 that while the custom has been to purchase largely complete fertilizers 

 of the lower grades, the tendency is now in the direction of the higher 

 grades. 



composition of complete fertilizers in different classes. 



If we compare the four different classes of complete fertilizers in 

 respect to the average amounts of nitrogen, available phosphoric acid, 

 and potash contained in them, we have the following results in tabu- 

 lated form: 



Table I. — Composition of Different Grades of Fertilizers. 



Class of Fertilizers. 



Low-grade 



Medium-grade .... 

 Medium high-grade 

 High-grade 



In 100 Pounds of Fertilizer. 



Pounds of 

 nitrogen. 



1.01 

 1.61 

 2.09 

 3.70 



Pounds of 



available 



phosphoric 



acid. 



8.12 

 8.28 

 8.00 

 7.78 



Pounds of 

 potash . 



3.22 

 4.67 

 7.94 

 7.89 



Pounds of 

 total 

 plant- 

 food. 



12.35 

 14.56 

 18.03 

 19.37 



In the last column, under the heading " pounds of total plant-food," 

 we give the sum of the amounts of nitrogen, available phosphoric acid 

 and potash. We notice the following points in connection with this 

 table: 



(1) The percentage of phosphoric acid does not vary greatly in the 

 different classes of fertilizers, being about 8 per ct. 



(2) The percentage of nitrogen and of potash increases in the higher 

 grades, though it is to be noted that the amount of potash in the two 

 highest grades is essentially the same. 



(3) The total amount of plant-food in 100 pounds of fertilizer in- 

 creases in the higher grades, this increase being due to increase of 

 nitrogen and potash. 



(4) Representing the amount of nitrogen in each class as 1, we have 



