524 NATURE AND PROPERTIES OF SOILS 



means of a covered barnyard. Siicli a yard should have a 

 more or less impervious floor. The manure is spread out in 

 the yard and is kept thoroughly packed as well as damp by 

 the animals. This is a common method of handhng the ma- 

 nure in the fattening of steers in the Middle "West and pro- 

 duces manure at a minimum loss, providing hogs are not al- 

 lowed to follow the steers. The storage of manure in deep 

 stalls, a favorite method in England, is similar to this system 

 and has been shown to be very economical. It also affords an 

 opportunity for the mixing of the manure from different 

 classes of animals. The desirability of this has already been 

 shown in the case of horse and cow excrements. The advan- 

 tages of trampling, so far as the keeping qualities of manure 

 are concerned, are clearly shown by the following figures 

 taken from the work of Prear : ^ 



Table CXYI 

 loss of manure in covered sheds. 



Condition 



Percentage Loss of 





NH3 



K2O 



P.O. 



Covered and tramped 



Covered and untramped 



5.7 

 34,1 



5.5 



19.8 



8.5 

 14.2 







Throwing manure in heaps under a shed and allowing hogs 

 to work the mass over, is a desirable practice so far as food 

 utilization is concerned. It interferes, however, with a proper 

 and economical packing of the manure. The question to be 

 decided is whether the added food value of the manure over- 

 balances the extra losses by decomposition incurred by the 

 rooting of the swine. 



301. Increased value of protected manure.— From the 

 previous discussion, it is evident that a well-protected and 



^ Prear, W., Losses of Manwe; Pa. Agr. Exp. Sta., Bui. 63, 1903. 



