The Bulletin. 



67 



as may be necessary to furnish tbe desired quantities of plant food, 

 having in mind that it is the specific number of pounds of phosphoric 

 acid, nitrogen and potash that is desired rather than a given weight 

 of mixed fertilizer. 



It is not more, but perhaps less difficult to calculate the number 

 of pounds of nitrogen, phosphoric acid and potash to be applied per 

 acre to any given crop from materials which are to be had than to 

 estimate the exact number of pounds of the materials to make a 

 formula of a certain composition, as for example, in an 8-2-2 goods. 

 The question of filler does not have to be considered in doing this, 

 as is necessary in making a fertilizer formula in the usual way. 

 When it is desired, for instance, to apply the equivalent of 500 

 pounds per acre of a fertilizer mixture containing 10 per cent avail- 

 able phosphoric acid, 1| per cent potash, and 5 per cent nitrogen, or 

 50 pounds phosphoric acid, 7^ pounds potash and 25 pounds of 

 nitrogen, it is only necessary to divide the number of pounds of plant 

 food desired per acre (50, 7^ and 25) by the percentage composition 

 of the materials to be used as follows : 



The best and most economical way to apply the fertilizer in the 

 quantities recommended here is in the drill before planting, though 

 there is no objection to dividing the application into two equal parts, 

 putting one-half in the drill before planting and applying the other 

 half as a side dressing around July first according to season and 

 growth of crop. The fertilizer in the quantity here suggested should 

 not be applied broadcast. 



