SILAGE— SOILAGE 207 



blower. The forage will settle considerably after the silo is filled, and 

 more may then be put in, any spoiled surface material being first 

 removed. If feeding is not to begin immediately, the surface should 

 be wet down thoroly and tramped well several times the first week, 

 when the rotting forage will fonn a layer on top that protects the rest. 

 To lessen the waste, it is well to remove the ears from the last few loads 

 of forage and cover the top witli cheap refuse such as straw or weeds, 

 wet with water. "When feeding begins, all spoiled silage should be 

 discarded. 



On going into the silo after an intermission in filling, one should 

 always beware of the danger from carbon dioxid. This may accumu- 

 late in sufficient quantities to prove fatal. If a lighted lantern or 

 candle lowered into the silo continues to burn, it is safe, but if the 

 light goes out it means death to one entering. Opening a door low 

 down in the silo or pouring in a lot of fresh cut forage will soon drive 

 out the deadly gas. 



Types of silos. — Silos may be constructed of wood, solid concrete, 

 concrete blocks, brick, stone, glazed tile, or sheet steel. In the semi- 

 arid regions pit silos, preferably with cement lining and curb, are 

 extensively used, but these are impracticable in humid climates. In 

 the southwestern states silos are sometimes built of adobe, reinforced 

 with wire and plastered with cement. The choice between the various 

 types of construction, all of which make good silos when well-built, 

 will depend upon local conditions. This work presents only the pri- 

 mary principles relating to silo construction, advising those interested 

 to secure from the state experiment stations or the United States 

 Department of Agriculture instructions concerning materials and man- 

 ner of construction suited to their locality. 



Requisites of a good silo. — The satisfactory silo meets the following 

 conditions: 1. Air-tight walls: The silo w^alls must be air-tight and 

 the doors fit snugly, for if air gains entrance the fermentations will 

 continue and molds will grow, spoiling the silage. 



2. Cylindrical shape. In the early silos, which were rectangular, it 

 was exceedingly difficult to pack the mass in the corners so that it 

 would not spoil. The cylindrical silo has no comers, the sides are 

 strong and unyielding, and it provides the largest possible cubic 

 capacity for a given amount of building material. 



3. Smooth, perpendicular, strong iralls. Unless the walls of the silo 

 are smooth and perpendicular, cavities will form along the walls as 

 the mass settles and the adjacent silage will spoil. The walls must be 

 strong and rigid, for while the silage is settling a great outward pres- 

 sure is developed. 



4. Depth. By making the silo deep the great pressure compacts all 



