6 



BULLETIN 1101, U. S. DEPARTMENT OF AGRICULTURE. 



A COW digesting her feed utilizes on the average approximately 25 

 per cent of the nitrogen, 30 per cent of the phosphorus, and 15 per 

 cent of the potash contained in the feed. It is evident, then, that 75 

 per cent of the nitrogen, TO per cent of the phosphorus, and 85 per 

 cent of the potash are voided in the urine or in the solid portion of 

 the manure. 



Dairymen who wish to reduce their net cost of production should 

 remember two important facts in regard to manure: First, that a 

 large proportion of the fertility value represented by the purchase 

 price of the feeds may be recovered by saving all the liquid and 

 solid portions of the manure; and, second, that the urine is more 

 valuable than the solid manure as a source of that high-priced plant 

 food, nitrogen. One of the big losses in liquid manure on many 

 farms is due to leaky floors in the stable. 



Table 4. — Credits for manure and fertilizing constituents during the two unnters 



and the two summers. 



' 



Winter. 



Summer. 



Item. 



1919-20 



1920-21 



Aver- 

 age.i 



1919- 

 202 



1920- 



212 



Aver- 

 age.i 



Total manure saved tons. . 



Manure per cow pounds. . 



Manure credited per 100 pounds of milk do 



656.0 



5,269 



180 



3 515.7 



3,806 



150 



585.9 



4,506 



165 



153.8 



1,238 



47 



81.4 

 558 

 20 



117.6 

 870 



S2 





Winter average. 



Summer average. 





Nitro- 

 gen. 



Phos- 

 phoric 

 acid. 



Pot- 

 ash. 



Nitro- 

 gen. 



Phos- 

 phoric 

 acid. 



Pot- 

 ash. 



Fertilizing constituents in manure pounds. . 



Credit per cow do 



6,035 

 23.2 



2,226 

 8.6 



4,922 

 18.9 



1,211 

 4.5 



447 

 1.7 



988 

 3.7 



1 The averages are weighted. 



2 See notes to Table 1. 



3 Not as large a proportion of the manure voided the second year was saved. 



According to Table 4, an average of 4,506 pounds, or slightly over 

 2.2 tons, of manure was saved per cow during the winter six months. 

 A 1,000-pound cow voids about 6^ tons of manure in six months. 

 The difference between these two amounts shows the quantity which 

 was voided in the yards or was lost in storing or handling. This was 

 due to the fact that much of the manure, especially the liquid portion, 

 was lost through the floors in the barns or allowed to leach away when 

 stored in piles exposed to the weather. Only the manure which was 

 or could have been saved by using reasonable care with the equipment 

 available was credited to the cows. The quantity of manure dropped 

 was approximated by keeping a record of the time the cows were 

 actually in the barn. 



