112 Agricultural Chemistry. 



other constituents may exert an important influence upon the 

 soil. 



Barnyard manure. Of all fertilizers, barnyard manure is the 

 oldest and still the most popular. It consists of the liquid and- 

 solid excreta of the farm stock, plus the litter employed. Early 

 Roman writers called atttention to the fact that the application 

 of the excreta of farm animals resulted in increased production, 

 and from that time to the present the majority of farmers have 

 placed their reliance on this class of manures for maintaining 

 the fertility of the land. 



A well kept manure heap may safely be taken as one of the 

 surest indications of thrift and success in farming. Neglect of 

 this resource causes losses which, though little appreciated, are 

 vast in extent. " Waste of manure is either so common as to 

 breed indifference, or so silent as to escape notice. According 

 to recent statistics there are in the United States in round num-* 

 bers, 19,500,000 horses, mules, etc., 61,000,000 cattle, 47,000,000 

 hogs and 51,600,000 sheep. Experiments indicate that if these 

 animals were kept in stalls or pens throughout the year and thq 

 manure carefully saved, the approximate value of the fertilizing 

 constituents of the manure produced by each horse or mule an- 

 nually would be $27, by each head of cattle $20, by each hog $8j 

 and by each sheep $2. The fertilizing value of the manure pro- 

 duced by the different classes of farm animals in the Uniteij 

 States, would therefore be for horses, mules, etc., $526,500,000; 

 cattle $1,220,000,000; hogs, $376,000,000, and sheep, $103,200,- 

 000, or a total of $2,225,700,000. These estimates are based on 

 the values usually assigned to phosphoric acid, potash and nitroj 

 gen in commercial fertilizers, and are possibly somewhat too higll 

 from a practical standpoint. On the other hand it must be bornij 

 in mind that no account is taken of the value of manure for im- 

 proving the mechanical condition and drainage of soils, which is 

 fully as important a consideration as its direct fertilizing value." 



It is fair to assume that at least one-third of the value of the 

 manure is annually lost through careless methods of manage- 



