The Bulletin. 



27 



Kainit, manure salt, sulphate or muriate of potash may furnish 

 the potash, and acid phosphate the phosphoric acid. 



Three hundred pounds of the above mixture would contain thirty 

 pounds of available phosphoric acid, 4| pounds potash and 15 pounds 

 nitrogen; and 500 pounds would contain 50 pounds available i)hos- 

 phoric acid, 7i pounds potash and 25 pounds nitrogen. The required 

 amounts of phosphoric acid in 300 and 500 pounds respectively of 

 this mixture would be supplied by 214.3 pounds and 357.1 pounds 

 of 14 per cent acid phosphate; the nitrogen by 115.4 pounds and 

 192.3 pounds of 13 per cent dried blood, and the potash by 22.5 

 pounds and 37.5 pounds of manure salt. Other materials or other 

 grades of these materials may be used, and it will not be difficult, 

 knowing just what they contain, to use such quantities of them as 

 may be necessary to furnish the 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. 



