AGRICULTURAL EXPERIMENT STATION. 57 



The average amount of manure from one cow is estimated at 

 9 tons, or 2 1-4 tons of dry matter. One ton contains about 15 

 pounds of potash and 7 pounds of phosphoric acid. The 

 milk of a single cow, therefore, contained as much potash as 

 three-fourths of a ton of the manure, and as much phosphoric 

 acid as two tons. 



As nitrogen is not contained in the ash, it has not been noticed 

 here. But in view of the fact that it is found in large quan- 

 tities in milk and is the most valuable ingredient of manures it 

 should be considered. Six thousand eight hundred^ and [fourteen 

 pounds of milk, the average product of one cow, contains 37.48 

 pounds of nitrogen (.55 of one per cent.) worth at least 15 cents 

 per pound, or $5.62 per year for the milk of a single cow. One 

 ton of manure contains about 12 pounds of nitrogen, worth $1.80. 

 The milk from a single cow, therefore, contains in one year as 

 much nitrogen as three tons of manure. As in the case of the 

 other constituents, however, the greater part of this is retained in 

 the skimmed milk. 



2W 



