14 



CONTROL SERIES No. 45 

 Mixing Efficiency Table. 



The above table shows that 21 of the 24 manufacturers Usted had an average 

 overrun in all three elements, although in some cases it was much too small 

 for safety. Twenty-two showed an overrun and two a shortage in nitrogen, 

 and 23 showed an overrun and one a shortage in both available phosphoric acid 

 and potash. 



Variations in the composition of the crude stock materials which make up 

 the average fertilizer mixture make it necessary that a liberal margin of overruns 

 be provided in figuring the formula, otherwise accidental shortages are sure to 

 be frequent in the assembled goods. 



Nitrogen in Mixed Fertilizers. 



In all of the mixed complete fertilizers analyzed for 1928, tonnage sold taken 

 into consideration, the average total nitrogen found was -3.96 per cent, which 

 was about the same as for the previous season. In 1918, the average total 

 nitrogen found in Massachusetts was 2.85 per cent, which is 1.11 per cent under 

 the average for this season. The nitrogen derived from the mineral and organic 

 sources in 1928 is divided as follows: from ammoniacal compounds, 2.17 per 

 cent; from nitrates, .63 per cent, and from organic, 1.16 per cent. There seems 

 to be but little difference in the proportion of organic nitrogen found in the 

 present mixed fertilizers as compared with that of ten years ago. In 1918, 34.4 

 per cent of the average total nitrogen was derived from organic sources, as com- 

 pared with 29.3 per cent for 1928. In view of the fact that each year sees a 

 larger proportion of the abattoir and fish industry ammoniates being diverted 

 to the feed industry, it is likely that the processed low grade organic ammoniates 

 have been employed in increasing amounts to meet the demand for materials 

 to preserve a good mechanical condition in mixed fertilizers as well as to furnish 

 a part of the nitrogen in a more lasting form. Of the 1.16 per cent of organic 

 nitrogen found in this season's output of mixed fertilizers, .29 per cent was in 

 water soluble and .87 per cent in water insoluble form; the latter with few excep- 



