The Bulletin 51 



of potash. Indications are that a mixture containing 6 per cent avail- 

 ahle phosphoric acid, 6 per cent nitrogen and 1 to 2 per cent potash will 

 give close to if not the hest returns. Six per cent nitrogen is equal to 

 7.3 per cent ammonia. This mixture can be usually used at the rate 

 of 100 to 300 pounds per acre with fairly good returns and profits. 

 Large quantities cannot as a general thing be recommended for eastern 

 soils. 



The nitrogen may be all derived from blood, tankage, cotton-seed 

 meal or similar products, or in part from one or all of these and in part 

 from nitrate of soda or sulphate of ammonia. Nitrate of soda may be 

 used as the entire source of nitrogen when divided into two parts. 



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

 potash, and acid phosphate the phosphoric acid. 



One hundred pounds of the above mixture would contain 6 pounds of 

 available phosphoric acid, 1 to 2 pounds of potash and 6 pounds of 

 nitrogen; and 300 pounds would contain 18 pounds of available phos- 

 phoric acid, 3 to 6 pounds of potash and 18 pounds of nitrogen. The 

 required amounts of phosphoric acid in 100 and 300 pounds, respect- 

 ively, of this mixture would be supplied by 42.9 pounds and 128.6 

 pounds of 14 per cent acid phosphate; the nitrogen by 46 pounds and 

 138.4 pounds of- 13 per cent dried blood, and the potash by 5 and 10 

 pounds, and 15 and 30 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, nitro- 

 gen, and potash that is desired rather than a given weight of mixed 

 fertilizer. 



It is perhaps less difficult to calculate the number of pounds of the 

 three plant foods (N P K) to be applied per acre to any crop from 

 materials on hand than to estimate the exact number of pounds of the 

 material to make a formula of a certain composition, as for example 

 take an 8-2-2 fertilizer. 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 equiva- 

 lent of 300 pounds per acre of a fertilizer mixture containing 6 per cent 

 available phosphoric acid, 2 per cent potash and 6 per cent nitrogen, or 

 18 pounds of phosphoric acid, 6 pounds of potash and 18 pounds of 

 nitrogen, it is only necessary after multiplying by 100 to divide the 



