264 Bureau of Farmers' Institutes. 



for $40 a ton, each pound of nitrogen in this form costs about 

 12^ cents. As between these two forms, the nitrogen of one is 

 two and one-half cents a pound cheaper than the nitrogen of the 

 other, and it will, therefore, be found more economical to use 

 nitrate of soda rather than sulphate of ammonia, when special 

 circumstances do not require the use of the latter. Dried blood, 

 containing 13 per cent, of nitrogen, at $36 a ton, furnishes nitro- 

 gen at an approximate cost of 14 cents a pound. The nitrogen 

 in fish scrap may cost somewhat less. In such forms as wool 

 waste, ground leather and hair, nitrogen may be purchased at 

 much less, but these forms are not usually economical at any price. 



The cheapest possible manner in which farmers can provide 

 their crops with nitrogen is by means of such plants as clover. 

 These plants can supply themselves with nitrogen from the air, 

 and can thus store up nitrogen for future use in the soil. Nitro- 

 gen supplied in this way can be made, to a considerable degree, to 

 take the place of the nitrogen of commercial fertilizers, and at 

 a greatly diminished cost. By such means the use of the most 

 expensive of fertilizing materials can be greatly diminished and 

 much saving effected. 



Soluble phosphoric acid can in general be more cheaply pur- 

 chased in the form of dissolved rock than in the form of dissolved 

 bone or bone-black. 



Muriate of potash costs less than sulphate, and is, therefore, 

 more economical when its use answers one's purpose. With the 

 exception of a few crops, like tobacco, sugar beets, and potatoes, 

 muriate of potash can nearly always be used to advantage. Pot- 

 ash in the form of carbonate, as found in wood ashes, is apt to be 

 somewhat expensive. When ashes contain five per cent, of potash 

 and two per cent, of phosphoric acid and cost $10 a ton, each 

 pound of potash costs about eight cents, while in the form of 

 muriate of sulphate, the cost would be about one-half. It is 

 easily conceivable, however, that on acid and certain other soils 

 the use of ashes might prove economical. The only way of. tell- 

 ing with absolute certainty whether ashes will prove more eco- 

 nomical than other forms of potash is to make an actual trial. 



In applying fertilizers, bulk is often desirable, but in purchas- 

 ing commercial fertilizers, the object should be to secure as murk 

 nitrogen, potash and phosphoric acid in available forms as possible 

 for one dollar, instead of as many pounds as possible of fertilizer, 

 regardless of the amount of plant food contained in it. This is 

 particularly applicable to mixed fertilizers, which at present form 



