152 



DESCRIPTION OF FEEDING STUFFS 



ciently heavy to largely exclude the air in the siloed fodder and 

 thus secure a good quality of silage. In case of deep silos the loss 

 from spoiled silage on the top is smaller in proportion to the amount 

 of silage stored, and a smaller loss occurs while the silage is being 

 fed out. As the silage packs better in a deep silo than in a shallow 



„™^, one, the former kind of silos 



; will hold more silage per cubic 



foot than the latter (Fig. 28). 

 3. The silo m u s t have 

 smooth, perpendicular walls, 

 which will allow the fodder to 

 settle without forming cavities 

 along the walls. In a deep silo 

 the fodder will settle several 

 feet during the first few days 

 after filling. Any unevenness 

 in the wall will prevent the 

 mass from settling uniformly, 

 and air spaces thus formed will 

 cause the surrounding silage 

 to spoil. 



The walls of the silo must 

 be made rigid and very strong, 

 so as not to spring when the 

 siloed mass settles. The lateral 

 (outward) pressure of cut corn 

 when settling at the time of 

 filling is considerable, and in- 

 creases with the depth of the 

 silage, at the rate of about 

 eleven pounds per square foot 

 for every foot in depth of sil- 

 age. At a depth of 20 feet 

 there is, therefore, an outward 

 pressure of 220 pounds per square foot; at 30 feet, a pressure of 33'0 

 pounds. It is because of this great pressure that it was difficult to 

 make large, rectangular silos deep enough to be economical, since 

 the walls of such silos always spring more or less under the 

 pressure of the silage, and this seldom keeps as well in them as it 

 does in those whose walls cannot spring. In the round wooden silos 

 every board acts as a hoop, and, as the wood does not stretch much 

 lengthwise, there is but little danger of spreading of such walls ; it 



Fig. 28. — A good concrete silo costs more 

 than a wooden s'lo, but will last indefinitely 

 when properly cared for, and needs no atten- 

 tion beyond an application of a coat of pure 

 cement wash every two or three years. (Wis- 

 consin Station.) 



