READY-MIXED FERTILIZER IO3 



of the fertilizer. Add the products ; the sum is the com- 

 mercial value of the fertilizer. 



EXAMPLE. What is the commercial value of one ton of complete 

 fertilizer which the printing on the bags guarantees to contain 1.65 per 

 cent of nitrogen, 10 per cent of available phosphoric acid, and 2 per cent 

 of potash ? 



Plant-food Lbs. Cents Commercial 

 in one ton value 



Nitrogen i .65 % x 2000 Ibs. = 33 Ibs. 33x15= $ 4.95 



Available phos- 

 phoric acid 10% x 2000 Ibs. = 200 Ibs. 200 x 5= 10.00 

 Potash 2%X2ooolbs. = 40 Ibs. 40 x 5= 2.00 



$16.95 



The above calculation shows a commercial value of $16.95 when 

 nitrogen, phosphoric acid, and potash have the prices of 15, 5, and 5 

 cents a pound respectively. 1 



If the cash price asked by the dealer is many dollars per 

 ton above the estimated commercial value for that year, 

 a calculation should be made to learn what it would cost 

 for the farmer to make his own fertilizer by mixing together 

 acid phosphate, cotton-seed meal, and kainit, or other 

 chemicals. 



EXAMPLE. What will it cost to make a home-mixed fertilizer, having 

 the same composition as the fertilizer given in the table, with cotton-seed 

 meal at $22 per ton, acid phosphate (with 16 per cent available phos- 

 phoric acid) at $15 per ton, and kainit at $14 per ton? The price 

 asked for the ready-mixed fertilizer is $21 per ton. How much meal, 

 phosphate, and kainit must be mixed in order to obtain an equivalent, 

 but less expensive, fertilizer? 



1 These figures will answer for practice. To get the exact prices of nitro- 

 gen, phosphoric acid, and potash for any particular year, write to the State 

 Commissioner of Agriculture at the state capital. 



