810 



SILOS, THEIR CONSTRUCTION AND USES. 



Fio. 8. 



Though silos are generally constructed be- 

 low-ground, it is by no means necessary to 

 build them so. They can be 

 made above the surface as well 

 as below it, by using double 

 walls, as for the preservation 

 of ice, but one of the walls, at 

 least, should be air-tight, to 

 guard against the percolation 

 of air through whatever is 

 used to fill the space between 

 the walls. 



To effect the destruction of 

 organic matter, three things 

 are necessary : a temperature 

 at which changes can be car- 

 ried on; free oxygen, to pro- 

 duce new combinations ; and 

 moisture, as a medium for it to 

 work through. If either one 

 of these essentials is absent, 

 destruction would be prevent- 



Fio. 2. 



ed. It would be exceedingly difficult, either 

 to maintain a temperature so low, or to re- 

 move so much moisture from succulent vege- 

 tation, as to prevent destruction. The most 

 available resort is to exclude the free oxygen 

 of the air. In building a silo, the chief ef- 

 fort of the builder should, therefore, be to 

 secure the most perfect exclusion of air possi- 



FIG. 4. SECTION OF A PORTION or SILO. 



ble. This, it is true, will not prevent all change. 

 Where there is sufficient moisture present, as 

 there always is in green vegetation, and a me- 

 dium temperature, sugar will be changed into 

 lactic acid, but this change is little else than a 

 rearrangement of the atoms of sugar, without 

 involving any destructive disintegration. It is 

 simply analogous to the changes which take 

 place in a mass of half-masticated herbage, 



lying wet and warm in the pouch of a rumi- 

 nant, by which the sugar assumes a new form, 

 that makes it more easily utilized by the living 

 organism. This change is inevitable, and will 

 occur whether oxygen, or air, is present or not; 

 but if no further change takes place, material 

 loss in the value of the food preserved will 

 not necessarily be sustained. The destructive 

 agents in a silo are alcoholic and acetic fer- 

 mentation. 



The work of filling a silo should be done 

 as rapidly as possible, in order that what is 

 first put in may not begin to heat and ferment 

 before the cover is laid on. For this reason it 

 is not advisable to make silos or their compart- 

 ments larger than to hold about 200 tons. 

 The majority of experience favors cutting the 

 fodder (especially corn) very short, a half inch 

 or less in length, but it can be safely preserved 

 whole, and cut afterward if desired. When 

 any considerable amount is to be cut, steam- 

 power is preferred. A ten horse-power engine 

 will cut fine 10 tons per hour, or 100 tons a 

 day, including necessary stops, so that a 200- 

 ton compartment can be tilled in two days. 

 Filling thus rapidly makes the work secure 

 against heating or other exposure. A louger 

 time in filling would not be fatal to results, but 

 the shorter the time the better. While the till- 

 ing is going on, the surface should be kept as 

 level as possible, and the corners well filled in 

 and trodden down, in order that the whole may 

 settle alike. If unevenly packed, and some 

 places sink more than others, the covering will 

 be liable to warp and injure, and open crevices 

 for the admission of air. The best covering 

 yet devised consists of sound, two-inch plank, 

 grooved together in sections, two and a half to 

 three feet wide, for convenience in handling, 

 and long enough to reach across the silo, 

 usually sixteen feet. The sections are also 

 joined with grooves and tongues, making the 

 whole air-tight. As these sections will come 

 apart easily, they are very con- 

 venient for removing, one at a 

 time, when feeding the ensilage, 

 so that no more surface will be 

 exposed than what is desired for 

 cutting down at once. 



As soon as the silo is filled, the 

 covering should be laid on at once, 

 and immediately weighted down 

 with stone or other weights, at 

 the rate of 200 to 250 pounds to 

 each square foot of surface. When 

 the settling is done, the joints 

 around the edges of the cover may 

 be cemented, to prevent any possible admis- 

 sion of air. Thus protected, the contents will 

 remain sound for an indefinite time. 



The destructive agents in a silo are alcoholic 

 and acetic fermentation. They can not occur 

 without the contact of air, and are therefore 

 not necessary accompaniments of ensilage. 

 They can be avoided first, by excluding air 

 from the silo ; and, secondly, by feeding the en- 



