14 DEPARTMENT OF AGRICULTURE. 



One pound of actual nitrogen would therefore cost 1/300 of $90=30 cents. 



Similarly, superphosphate contains 16 per cent, available phosphoric acid. 



One ton contains 16 per cent, of 2,000 Ib. or 16/100 of 2,000=320 Ib. 



If the commercial value is $32 per ton, 320 Ib. of available phosphoric acid costs 

 $32. 



One pound of available phosphoric acid therefore costs 1/320 of $32=10 cents. 



Similarly, muriate of potash contains 50 per cent, actual potash. 



One ton contains 50 per cent, of 2,000 Ib. or 50/100 of 2,000=1000 Ib. 



If the commercial value of muriate of potash is $150 per ton, 1,000 Ib. of actual 

 potash costs $150. 



One pound of actual potash would therefore cost 1/1000 of $150=15 cents. 



A mixed fertilizer is guaranteed as a 4-9-5 fertilizer. A ton would contain the 

 following amounts of plant-food : 



Nitrogen, 4 per cent. ; therefore 1 ton contains 4/100 X 2,000 = 80 Ib. 



Available phosphoric acid, 9 per cent. ; therefore 1 ton contains 9/100 X 2,000 = 

 180 Ib. 



Potash, 5 per cent. ; therefore 1 ton contains 5/100 X 2,000 = 100 Ib. . 



A ton of mixed fertilizer guaranteed to contain 4 per cent, nitrogen, 9 per cent 

 phosphoric acid, and 5 per cent, potash consists of 80 Ib. actual nitrogen, 180 Ib. 

 actual available phosphoric acid, and 100 Ib. actual potash. 



Having calculated the value per pound of these three plant-foods when purchased 

 singly, it is not difficult to estimate whether it is more economical to ftuy a mixed 

 fertilizer. 



The value of a 4-9-5 fertilizer based on the commercial values of the nitrate of 

 soda, superphosphate, and muriate of potash quoted above would be : 



80 Ib. nitrogen at 30c $24 00 



180 phosphoric acid at lOc 18 00 



100 potash at 15c 15 00 



Total $57 00 



Added to this is the manufacturer's charges for mixing. 



No fertilizer contains 100 per cent, plant-food; therefore purchasing by the ton 

 without calculating the number of pounds of actual plant-food contained in each 

 ton is not a safe practice. 



On soils that are deficient in humus or rotted vegetable matter the organic 

 fertilizers have a value in access of their actual plant-food content owing to their 

 effect in improving the physical condition of the soil. 



MIXING FERTILIZERS. 



The operation of home-mixing must be thoroughly done or the result may prove 

 unsatisfactory. Select a clean dry floor, preferably of concrete, and dump the 

 fertilizers in their required proportions in a heap. After thoroughly mixing with a 

 shovel the whole should be passed through a %-inch mesh screen. If the bulk to 

 be applied to an acre is less than half a ton the quantity should be increased by 

 adding fine dry sand or earth. 



Some fertilizers cannot be mixed on account of unfavourable chemical action. 

 To avoid trouble do not mix the following : 



(1.) Lime, wood-ashes, or basic slag with any fertilizer containing ammonia, 

 such as ammonium sulphate, farmyard manure, or organic manure. 



(2.) Lime, wood-ashes, or calcium cyanamide with any fertilizer containing 

 soluble phosphate, such as superphosphate or dissolved bones. 



(3.) Nitrate of soda with superphosphate or dissolved bones, except for 

 immediate application, and under no circumstances if the superphosphate or bones 

 be not in a fine dry condition. 



(4.) When muriate of potash and other potash salts are mixed with super- 

 phosphate a hard cement-like mass is likely to form if the mixture is not spread 



