12 Silo Construction in Nebraska 



and furthermore the air in the silo is warmer than the outside 

 air, hence air currents are set up which carry the gases away. 



TYPES OP PIT SILOS. 



There are three types of pit silos: (1) The plain hole in the 

 ground which very much resembles a dug well without any curb- 

 ing; (2) the semi-pit silo which has a part of the silo above 

 ground and a part located in the ground; and (3) the bank silo, 

 which is a silo either located on the bank in such a way that by 

 tunneling in at the bottom a chute can be made up along the silo 

 similar to that of a silo which sets above ground, or where the 

 silo sits so close to the bank that the silage can simply be 

 thrown out at the doors and permitted to drop to the ground. 

 Probably this last type of silo is the most convenient and in- 

 expensive and most satisfactory of any silo that can be con- 

 structed. 



CONSTRUCTING PIT SILOS. 



The pit silo is built down instead of up. The first operation 

 is to dig a trench around the top which has an inside diameter 

 the same as the inside diameter of the silo. This trench should 

 be as narrow as can be conveniently dug with a spade and as 

 deep as the spade will conveniently reach. Fill the trench with 

 concrete and when it has set remove the dirt from inside, down 

 to a depth of about six feet. 



When this depth is reached, the silo walls should be plastered. 

 A mixture of one part of cement to two and one-half parts of 

 screened sand is the best proportion for the plaster. Layers 

 should be plastered on until the coat of plaster is about three- 

 quarters of an inch thick or more. It will take two or three 

 coats to do this. 



After the first section of the silo has been plastered, then take 

 out about six feet more of earth and plaster this in the same 

 manner. Continue this process until the proper depth is reached. 



By digging and plastering a silo in this manner there is no 

 need of staging, and one has a good strong floor upon which to 

 work. 



When the bottom of the silo is reached, the floor can be put 

 in if desired. However, it is not material whether the silo has 

 a floor or not. 



If a part of the silo is to be built above the ground, it can 

 be built before the dirt is thrown out, or afterwards, depending 

 upon the convenience of the farmer. 



There are three ways to build that part of the silo which is 

 above ground. One is to make a form and build it of solid con- 



