46 THE POTATO 



mature fattening animals. The food and the litter 

 used also affect the value of the manure. 



In barn manure the nitrogen, phosphoric acid and 

 potash are slowly available, and are arbitrarily reck- 

 oned to be worth half what they would cost in fer- 

 tilizers. The value of a ton of manure for its physical 

 effect upon soils cannot be expressed in dollars and 

 cents, but in the Eastern States it may be presumed to 

 vary between 50 cents and $1.00 per ton; for while the 

 fertilizing ingredients show a value of about $1.25, 

 the manure often costs, or is valued at, $2.00 per ton. 



Mixing Fertilizers. Fertilizer manufacturers lay 

 great emphasis on the value of proper mixing, and 

 usually charge from $5 to $10 per ton for doing it. 

 For example, a commercial potato manure analyzing 

 nitrogen, 3 percent., phosphoric acid, 6 per cent., and 

 potash, 10 per cent, costs in New Hampshire', in 1904, 

 $36.50 per ton. A fertilizer made up by the station 

 on the same formula was just as satisfactory, and 

 after allowing $1.00 per ton for mixing, it cost $24 

 per ton, a saving of $8.50 per ton, or using 1,500 

 pounds per acre = $7.10 per acre. 



To compound this fertilizer: 

 3 per cent, nitrogen = 60 pounds nitrogen in a ton 



(2,000 pounds). 

 6 per cent, phosphoric acid = 120 pounds phosphoric 



acid in a ton. 

 10 per cent, potash = 200 pounds potash in a ton. 



Nitrate of soda will furnish nitrogen for immediate 

 use, and the nitrogen of the sulphate of ammonia will 



