FERTILIZER PRACTICE 567 



476. How to mix fertilizers. As the various carriers 

 are bought under guarantee, the percentages of nitrogen, 

 phosphoric acid, and potash in the ingredients to be mixed 

 are accurately known. The calculation of the amounts 

 of each carrier and of the filler necessary to make up a 

 ton of a fertilizer having a certain formula, then becomes 

 a matter of simple arithmetic. The mixing is an equally 

 simple operation. The implements needed in home mixing 

 are as follows: (1) a tight floor, (2) platform scales, 



(3) a sand screen with from three to six meshes to an inch, 



(4) a tamper or a grinder, (5) shovels, a rake, and like 

 tools. 



First, the various ingredients, after being crushed and 

 screened if lumpy, are weighed out in amounts sufficient 

 for the unit of fertilizer to be mixed at any one time. 

 The bulkiest material is spread on the floor first and leveled 

 uniformly by raking. The remaining ingredients are 

 then spread in thin layers above the first, in the order 

 of their bulk. Beginning at one side, the material is 

 next shoveled over, care being taken that the shovel 

 reaches the bottom of the pile each time. The pile is 

 then again leveled, and the process is repeated a sufficient 

 number of times to insure thorough mixing. Sometimes 

 a mixing machine may be used for this operation. For 

 storage and general convenience, the fertilizer may be 

 weighed into sacks of from 100 to 150 pounds capacity 

 and put in a dry place until needed for use. 



A word of caution should be inserted here regarding the 

 concentration of the mixture. Some farmers, in order 

 to lessen the work of mixing and application in the field, 

 raise the percentage of the elements exceedingly high 

 a condition very likely to occur when high-grade materials 

 are used. This is bad practice, in that it may interfere 



