228 



SOILS AND FERTILIZERS 



materials that are soluble in water and that consequently 

 represent the most valuable part of the manure. As about 

 one-half of the nitrogen and two-thirds of the potash of farm 

 manure is in a soluble condition, the possibility of loss by 

 leaching is very great. Even phosphoric acid may thus 

 be removed. 



It is rather difficult to distinguish between the losses due 

 to fermentation and those caused by leaching. In an experi- 

 ment conducted in Canada a carefully mixed quantity of 

 farm manure was divided into two parts, one of which was 

 placed in a bin under a shed, the other was exposed to the 

 weather outside, in a similar bin. After a year the two por- 

 tions were analyzed and the losses thus computed are stated 

 in the following table. 



Table 50. 



Losses by Fermentation Alone and by Fermen- 

 tation and Leaching Combined 



Constituent Lost 



Percentage Loss 



Organic matter 

 Nitrogen . 

 Phosphoric acid 

 Potash . . . 



288. Protected manure more effective. — Over a period 

 • of fourteen years, in a three year rotation of corn, wheat 

 and hay at the Ohio Experiment Station, stall manure gave 

 an average yield of 30 percent more than did equal quantities 

 of yard manure. This gives a fair basis on which to cal- 

 culate whether it would pay to protect the manure when the 

 expense of doing so, and the quantity of manure produced, 

 are considered. 



