270 ELEMENTARY TREATISE ON STOCK FEEDS AND FEEDING 



barley to show its almost permanent effect. A plot of grass 

 land received 14 tons of farm manure per acre for 8 years and 

 was then left unmanured. For the two years following the dis- 

 continuance of manure the crop was double that of the un- 

 manured plot; yet the yield has slowly declined from year to 

 year but has averaged 15 per cent, more than the unmanured 

 plot. The barley experiment is as follows : The first plot re- 

 ceived an application of 14 tons of farm manure per acre for 

 20 years (1852-71) and since that time has been left unmanured. 

 Another plot has been left unmanured during the entire period 

 since 1852. The yield on the first plot for twenty years after 

 the application of manure was discontinued, was 30 bushels 

 per acre per year, while the unmanured plot where nothing was 

 applied gave an average yield of 13 bushels per acre per year. 

 Amount of Manure Voided by Animals. — It is estimated by 

 Heiden that for every 100 lbs. of dry matter fed there are, 

 210 pounds of fresh manure voided by the horse, 

 380 pounds of fresh manure voided by the covr, and 

 i8o pounds of fresh manure voided by the sheep. 



Snyder^ estimates that a well fed horse will produce about 50 

 lbs.*of manure per day of which one quarter will be urine. A 

 horse will produce about 6 tons of manure per year in the stable. 

 A milch cow will produce from 60-70 lbs. of total manure of 

 which 20-30 lbs. are liquid. He estimates that a well fed cow 

 will produce about 80 lbs. of manure per day including absorbents. 



Composition of Manure. — The following table gives the compo- 

 sition of solid and liquid manure from some farm animals : 



The above table shows that the liquid portion is richest in 



1 "Soils and Fertilizers." 



2 Approximate. 



