RELATION OF FOOD TO MANURE 



313 



with wheat and clover without further manuring or 

 fertilizing. The table following shows the average 

 increase of each crop for both kinds of manure : 



YARD AND FRESH MANURE COMPARED 



In discussing these tests, Director Thorne says 

 that not only was the manure greatly reduced in 

 quantity, but the quality likewise was impaired by 

 exposure, the rain leaching out the most soluble and 

 therefore the most valuable portion. At current 

 prices the average increase from a ton of open yard 

 manure, including the straw and stover, was worth 

 about $2, while that from the fresh manure reached 

 an average value of nearly $3, and this value was in- 

 creased to $4.50 when the manure was reinforced 

 with acid phosphate. 



That manure materially decreases in bulk and 

 plant food value is shown in an experiment recorded 

 by Professor Roberts. Starting with 4,000 pounds 

 of manure the amount decreased to 1,730 pounds; 

 because of poor preservation 60 per cent of the nitro- 

 gen escaped into the air; and 75 per cent of the 

 potassium and 40 per cent of the phosphorus leached 

 away in rain water. When this pile of manure is 

 considered from the standpoint of money value, it is 

 found that at the beginning it was worth $5.48; but 



