INSPECTION OF COMMERCIAL FERTILIZERS 9 



(b) Tonnage of Unmixed Fertilizing Materials. 



In order to conform to the recommendation made by the Committee on Defini- 

 tion of Terms and Interpretation of Results on FertiUzers at their meeting in 1928, 

 as well as to the vote of the National Fertilizer Association, the percentage of 

 nitrogen is used instead of ammonia in expressing the grade of a fertilizer both in 

 the tables of analysis and in the text of the bulletin. For this season, this auto- 

 matically throws into the low-analysis group some of the grades previously appear- 

 ing in the high-analysis group and representing some of the largest tonnages. It 

 is also more or less confusing to the reader who attempts to compare the tonnage 

 of this year with previous years on any fertilizer grade. In the tonnage tables, 

 however, the percentage of ammonia is given in parenthesis following the figiu-e 

 for nitrogen, so that such comparisons are possible. It is hoped that before 

 another season the fertilizer manufacturers may unanimously adopt the recom- 

 mendations of their association and state the nitrogen guarantee when expressing 

 the grade of a fertilizer. It will help to avoid further confusion if the guarantee is 

 raised in all cases so that the nitrogen statement is the same as the ammonia 

 statement formerly used. This, of course, would result in a somewhat higher 

 schedule of prices than would naturally prevail if the former system of expressing 

 grade were in force. Even so, it should not result in greater expense in the pur- 

 chase of plant food. 



In comparing the tonnage of some of the more popular grades this season with 

 that of the previous year, we find that the three grades having the largest tonnage 

 in 1929 were 4.11 (5)-8-7, 3.29 (4)-8-4, and 4.11 (5)-3-5. The first two had the 

 largest tonnages in 1928. The third largest tonnage in 1928 was from the 2.47 

 (3)-8-4 grade, which in 1929 occupies the fourth position. It is interesting to noto 

 that the grade having the third largest tonnage this season, 4.11 (5)-3-5, is hsted 

 in the low-analysis group, as are also three other tobacco brands. The combined 

 tonnage of these four grades was 5,306. These four grades represent the highest, 

 individual tonnages in this low-analysis group. 



