EXTENSION COURSE IN SOILS. 
55 
BARNYARD MANURES. 
(Ref. 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 by 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 when 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 
Pounds. 
0.872 
.061 
.039 
.772 
1.33 
2.75 
.67 
.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 barnyard 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 
