EXTENSION COUESE IN SOILS. 



55 



BARNYARD MANURES. 



(Kef. No. 1, pp. 113-121; or No. 7, pp. 316-347; or No. 9, pp. 229-236; or No. 6, 

 pp. 131-148; No. 5, pp. 541-543; No. 4, pp. 158-160.) 



Materials retained and voided hy animals. — Much of the plant food 

 removed from the soil by crops may be returned in the manure from 

 animals to which the crops are fed. The actual amount of plant food 

 so returned depends on the quantity absorbed by animals in their 

 bones and flesh or converted into milk, and on the loss from the 

 manure before it is returned to the soil. The more digestible the 

 food and the younger the animal the larger is the portion retained in 

 the form of bone and flesh. Hall, in England, found that when lin- 

 seed cake was fed to fattening steers and milch cows, the distribu- 

 tion of the nitrogen, phosphorus, and potassium were as shown in 

 Table III. 



Table III. — Distribution of nitrogen, phosphorus, and potassium contained in linseed 

 cake token fed to fattening oxen and milch cows. 



Nitrogen. 



Phospho- 

 rus. 



Potassium. 



Content of 100 pounds of linseed cake 

 When fed to fattening oxen: 



Retained in meat 



Voided in urine 



Voided in dung 



When fed to milch cows: 



Retained in milk 



Voided in urine 



Voided in dung 



Pounds. 



4.75 



.21 



3.88 



.66 



1.33 



2.75 



.67 



Pounds. 

 0.872 



.061 

 .039 



.772 



.218 

 .031 

 .623 



Pounds. 

 1.162 



.017 

 .913 

 .232 



.116 

 .872 

 .174 



This table is of special value in showing the comparative quantities 

 of nitrogen, phosphorus, and potassium retained in meat and milk; 

 also in the comparative quantities of these essential elements shown 

 to be voided in liquid and solid excrement. It emphasizes the cost 

 of producing milk from the fertility standpoint, and it clearly shows 

 the importance of saving the liquid manure and returning it to the 

 soil. Hopkins shows that as a general average for dairy farming, 

 cattle feeding, and sheep feeding, practically one-third of the organic 

 matter, three-fourths of the nitrogen, and three-fourths of the phos- 

 phorus contained in the feed and bedding are recovered in the total 

 manures. Nearly all of the potassium may be recovered except that 

 sold in milk. 



Value of harnyard manure. — From a large number of chemical 

 analyses it has been determined that the average sample of fresh 

 manure, including bedding used in absorbing the urine, contains 

 about 10 pounds of nitrogen, 2 pounds of phosphorus, and 8 pounds 

 of potassium per ton of material, varying with the age of the animal 

 and the feed. Estimated upon the fertility value of the three essen- 

 tial elements nitrogen, phosphorus, and potassium, fresh barnyard 



