8 BULLETIN 923, U. S. DEPARTMENT OF AGRICULTURE. 
Table 6. — Credit for manure and fertilizmg constituents ty seasons — Continued. 
Winter. 
Summer. 
Item. 
Nitrogen. 
Phos- 
phoric 
acid. 
Potash. 
Nitrogen. 
Phos- 
phoric 
acid. 
Potash. 
Manure 
Pounds. 
39,470 
1,145 
Pounds. 
13,005 
397 
Pounds. 
42,102 
2,854 
Pounds. 
7,587 
Pounds. 
2,525 
Pounds. 
8,152 
Total fertilizing constituents 
40,615 
13,402 
44,956 
7,587 
2,525 
8,152 
Credit per cow 
49.6 
16.4 
54.9 
8.7 
2.9 
9.3 
The average credit allowed for manure and bedding each year in- 
cludes the manure from the bulls, and represents what was or could 
easily have been saved under local conditions. Since the total cost of 
keeping bulls is charged against the cows, the bull manure is included 
as a direct credit to the herd, and the combined credit was estimated 
to be 5.3 tons per cow. 
The fertilizing constituents in 1 ton of average manure and bed- 
ding from the cows during the winter were estimated to be as follows : 
Pounds 
per ton. 
Nitrogen 10. 8 
Commercial phosphoric acid 3.5 
Potash 11.9 
Without bedding, 1 ton of average winter manure was estimated to 
contain: 
Pounds 
per ton. 
Nitrogen 10. 7 
Commercial phosphoric acid 3. 5 
Potash 11. 4 
The fertilizing constituents in the manure and bedding were valued 
at the following prices a pound during the first year : Nitrogen, 21 
cents ; commercial phosphoric acid, 6 cents ; and potash, 7 cents ; and 
during the second year : Nitrogen, 25 cents ; phosphoric acid, 6 cents ; 
and potash, 7 cents. 
On the average dairy farm the commercial value of manure de- 
pends upon the use to which it is put. The return in dollars depends 
upon the increase in the crops raised and the amount received from 
the sale of these crops. These facts may reduce or increase the value 
of manure below or above the market price of the fertilizing constitu- 
ents contained in it. 
REQUIREMENTS FOR KEEPING A BULL. 
The record on one bull for one month, called a bull month, was 
taken as a working unit. The bulls on about three-fourths of the 
farms were kept in the barn in the summer. This accounts for the 
