40 PRINCIPLES OF FARM PRACTICE 



the fanner and the honest manufacturer are protected. 

 Even with this safeguard, the farmer may be misled if he is 

 unable to understand the meaning of the analysis when he 

 reads it. 



Meaning of a fertilizer analysis. The record of a fertil- 

 izer analysis, as it appears on a package, may at first seem 

 confusing, especially if a complete analysis is given. A 

 simple rule, easily followed, is to consider only the lowest 

 stated amounts of available, or soluble, ingredients. The 

 following is an example of an analysis on a fertilizer tag with 

 an application of the rule: 



ANALYSIS 



Nitrogen i . 64 to 2 . 46 per cent 



Nitrogen as ammonia 2 .00 " 3 .00 " " 



Soluble phosphoric acid 5.00 " 6.00 " " 



Reverted phosphoric acid 3 .00 " 4.00 " " 



Insoluble phosphoric acid i .00 " 2 .00 " " 



Total phosphoric acid 10.00 " 12 .00 " " 



Phosphate of lime 22.00 " 24.00 " " 



Available phosphoric acid 8.00 " 10.00 " " 



Potash 3.00" 4.00" " 



Sulfate of potash 1.64 " 2.46 " " 



Applying the rule, 1.64 per cent nitrogen, 8 per cent 

 phosphoric acid, and 3 per cent potash are the only items to 

 be considered. In each case the lowest amount is taken, 

 for there is no guarantee that the higher percentage will be 

 found, although it may be. 



Ordinarily the analysis as indicated on a fertilizer tag is 

 not presented in as much detail as the above example. The 

 form of the certificate printed at the top of the following page 

 illustrates a more common practice: 



