FARM MANAGEMENT 137 



Exclusion of Air. The fundamental principle in the preser- 

 vation of green forage when placed in a silo is to exclude air as far 

 as possible from the silage and in this way prevent decay. To pre- 

 vent the air from reaching the silage all silos must have air tight 

 walls. These must be rigid enough not to be sprung out of shape 

 by the pressure of the silage, permitting air to enter next to the 

 wall. Not only the walls but the doors also, must be perfectly air 

 tight. To accomplish this they should be well fitted and the joints 

 made more perfect by felt pads or gaskets. It is good practice 

 where the silo door sets against a shoulder, to place clay worked into 

 the consistency of putty in the joint. The clay is placed on the 

 bearing surface and the door placed over it, and when the pressure 

 of the silage comes against the door an air tight joint is obtained. 

 Tar paper is successfully used by some silo owners either in strips 

 to cover the cracks around the doors, or in width sufficient to cover 

 the entire door and lap a few inches on the silo walls. 



Stave Silo. It is probable that no better material can be ob- 

 tained for the staves than Southern cypress. This, however, is so 

 expensive in some localities as to preclude its use in most cases. Of 

 the cheaper materials hemlock, white pine, and yellow pine are 

 usually the most available. At the present time hemlock is one of 

 the cheapest satisfactory materials which can be purchased and it is 

 probably as good as any of the cheaper materials. It should be 

 sound and free from loose knots. If the staves are left perfectly 

 plain, then when they are set in place and drawn together the first 

 point of contact will be the inner edge and the tighter the hoops 

 are drawn the closer will become the contact of the staves at the 

 inner edge. If it is impossible to purchase material for staves the 

 length of which shall be equal to the desired depth of the silo then 

 shorter staves may be used and set up. The staves should be sur- 

 faced on the inside so that a smooth face may be presented which 

 will facilitate the settling of the silage. Whether the outside of the 

 staves shall be planed is a matter of taste, but if hemlock is used the 

 handling of the staves will be found much easier if both sides are 

 planed. To prevent stave and wooden-hoop silos from becoming 

 displaced from their foundations by high winds and to prevent 

 creeping due to the swelling and shrinking of the wood, they should 

 be anchored with three or four three-eighths inch rods or wire cables 

 running from the eaves to the top of the foundation, or to anchors 

 buried in the earth a few feet from the base of the wall. Rods 

 with a hook or eye to which these stay rods or wires may be at- 

 tached can readily be embedded in the masonry of the foundation. 

 These stay wires can easily be made by stringing four No. 12 wires 

 loosely from tha eaves to the rods in the foundation and then twist- 

 ing them into a taut cable with a short stick. 



Concrete Silo. The single wall concrete silo is the most com- 

 mon style of construction. The thickness of the walls of silos now 

 in use varies from six inches at the bottom to four inches at the top 

 for the lightest wall to a wall two feet in thickness. Six inches seems 



