420 IOWA DEPARTMENT OF AGRICULTURE 



ESSENTIALS OF A GOOD SILO. 



An attempt is here made to outline the essentials or points of merit 

 to be found in the ideal silo. This is done in order that a direct comparison 

 may be made between this ideal silo and the Iowa silo. 



IMPEBVIOUSNESS OF THE WALLS. 



The fundamental principle involved in preservation of silage is the re- 

 tention of moisture within the silage and the exclusion of air. For this 

 reason, the silo wall must be non-porous. Moisture must be prevented from 

 passing out and air from passing in. 



RIGIDITY, STRENGTH AXD SMOOTHNESS OF WALLS. 



An ideal silo must have rigid walls. It must be strong enough to resist 

 the bursting pressure of the silage. This acts outward in all directions as 

 the silage settles. The friction of the silage against the wall, and the 

 weight of the wall produce a crushing action which is great near the bot- 

 tom of the silo. A silo when empty should be heavy enough to stand 

 against heavy winds. The inside of a silo wall should be reasonably 

 smooth to permit the silage to settle freely. If the wall is not smooth 

 or if there are shoulders or offsets on the inside surface air pockets will 

 be formed and a considerable loss of silage will result. 



DURABILITY. 



After due consideration to all other points of merit to be found in 

 silos, the most desirable silo is the one that is the most durable and 

 will give the longest term of service. The durability of a silo depends 

 first upon its strength, and second, the durability of the material used in 

 its construction. 



To be durable, any material must resist the action of the weather, the 

 constant wetting and drying, freezing and thawing in the winter season, 

 and any disintegrating action which may be due to the silage itself. 

 Some material will disintegrate with age, and other materials suffer 

 from rapid decay when subject to the warm, moist conditions which exist 

 in the silo. 



CARE AND REPAIR. 



It is desirable that a silo require the minimum expenditure in the way 

 of labor and material for its up-keep. A silo which must be adjusted for 

 shrinkage and expansion is of less value than one which does not need 

 such attention. Often this work is neglected, and loss results. 



Some silos must be frequently repainted in order to present a pleasing 

 appearance. This means added expense. All parts should be equally 

 durable and lasting. The replacement of pai'ts which are short-lived, the 

 substitution of new pieces for those which have become decayed or faulty 

 for any other reason, adds materially in many cases to the cost of main- 

 taining the silo. 



