SILOS AND SILAGE 151 



The figures for file capacity of silos given in the table refer to 

 Indian corn cut when nearly mature. Somewhat larger quantities 

 can be put in of immature corn or sorghum, and less of dry corn, 

 alfalfa, grain sorghums, and similar crops that do not pack well. 

 If cut when nearly ripe, the grain sorghums will occupy at least 

 one-third more space than Indian corn cut at the usual time, and the 

 capacity of a silo for these crops would then be decreased in this 

 ratio from the figures given in the table. 



Important Points in Building Silos. — The following points 

 should be kept in mind in building silos : 



1. The silo must be air-tight. The process of silage making is 

 largely a series of fermentation processes. Bacteria pass into the 

 silo with the green fodder and after a short time begin to multiply 

 there, favored by the presence of air and an abundance of feed 

 materials in the fodder, especially soluble carbohydrates. As a 

 result of this action, as well as of the respiration of the plant cells, 

 carbon-dioxide and heat are evolved. The more air at the disposal 

 of the bacteria, the further the fermentations will progress, and the 

 greater will be the losses of feed materials. If a supply of air is 

 admitted to the silo from the outside, the bacteria will have a 

 chance to continue to . grow, and more fodder will, therefore, be 

 wasted. If no further supply of air is at hand, except what remains 

 in the air spaces between the siloed fodder, the bacteria will gradu- 

 ally die out, or only such forms will survive as are able to grow in 

 the absence of air. The changes occurring in, siloed fodder are also 

 due in part to intramolecular respiration in the plant tissues, which 

 continues until the cells are killed. When there is available oxygen 

 in contact with the plant cells, these will live longer and the loss of 

 plant materials will be greater than when only a smaller supply of 

 air (oxygen) remains in the air spaces in the siloed mass. 



2. The silo must be deep. Depth in the silo is essential in mak- 

 ing silage so as to have the siloed mass under great pressure ; this 

 will cause it to pack well and will leave as little air as possible in 

 the interstices between the cut fodder, thus reducing the loss of feed 

 materials to a minimum. 



The early silos built in this country or abroad were shallow struct- 

 ures, often not over 12 to 15 feet deep, and were longer than they 

 were deep. Experience showed that it was necessary to weight heavily 

 the fodder placed in these silos in order to avoid a large amount of 

 moldy silage. In modern silos no weighting is necessary, since the 

 material placed in the silo, on account of the great depth, is suffi- 



