336 SOILS AND PLANT LIFE 



240. The Care and Importance of Barnyard Manure. — 



About eighty per cent of the essential elements contained in 

 the grain and hay fed to live stock is returned in the excre- 

 ment. If the manure, both solid and liquid, is carefully 

 preserved and returned to the soil without loss, only 

 about twenty per cent of the fertility contained in the crops 

 fed is lost from the land. Usually, however, the manure 

 is not properly handled ; and as a result, about one third 

 of the fertility which it contains is lost.. In this case, 

 but little more than half of the fertility taken from the 

 soil in the crops gets back to it again. 



It follows that no farm can maintain its fertility indefi- 

 nitely simply by feeding the crops which it produces to 

 live stock and returning the manure to the land. If the 

 fertility is to be maintained by means of barnyard manure, 

 it is necessary either to secure some from an outside source 

 to be added to that which the farm produces or to purchase 

 supplementary feeds or grain from others and feed them 

 on the farm. 



The chief losses of fertihzing elements from manure 

 occur in three ways : 



(1) The manure is not protected from rains, and much 

 of the fertility which it contains is leached, or washed out 

 of it. This may be prevented by protecting it by a suit- 

 able roof or by applying it at once to the fields. 



(2) The liquid manure is allowed to escape. Pound 

 for pound, it is more valuable than the solid manure, owing 

 to the large amount of nitrogen and potassium which it 

 contains. Sufficient bedding should be used to absorb 

 all of it, or it should be drained into a cistern to be ap- 

 plied later to the land. 



(3) Much loss results from fermentation, by which 

 nitrogen escapes in the form of ammonia. This fermenta- 

 tion may be detected by the heating and steaming of the 



