264 SOILS 



The experiments show a loss of twenty per cent, of the 

 total weight of the manure between January and April. 

 The loss in effectiveness is indicated by the fact that the 

 ton of fresh manure produced an average increase in the 

 three crops of the rotation to the value of $2.94, while 

 that from the same original quantity of manure, after 

 lying four or five months in the barnyard, amounted to 

 but $1.70, a loss of more than forty per cent. 



Chemical analyses made in January and April show that 

 the manure lost between these dates was twenty-two per 

 cent, of its total phosphorus, nearly fifty per cent, of its 

 total potassium, and more than forty per cent, of its total 

 nitrogen ; but when the water soluble constituents are de- 

 termined, it was found that, while the loss of phosphorus 

 retained practically the same proportion, that of potas- 

 sium amounted to fifty-four per cent, and that of nitrogen 

 to seventy-three per cent. 



Losses occur at all times during the year. It will be 

 observed that these experiments show only the losses that 

 may occur in exposed manure during a few months of 

 the winter, and it is probable that manure does lose in 

 value more rapidly during the first few months than later 

 on, through the leaching out of the liquid, and of the 

 more soluble portions of the solid manure ; but these 

 losses do not stop with the winter season, nor are they 

 confined to leaching; but with wanner weather fermenta- 

 tion becomes more active, and fermentation means not 

 only the combination of the nitrogen of the manure with 

 hydrogen and its escape as ammonia gas, but also the 

 conversion of the ash elements into more soluble forms, 

 in which they may be more readily leached out by sub- 

 sequent rains. The mere loss of total weight, however, is 

 not a safe guide as to the actual loss which may occur in 

 the manure heap. In its fresh condition a lot of manure 



