THE SILO
The Egyptians, the Romans, and the American Indians all stored grain in pits or silos which were air-tight, or as nearly so as large rude structures could be made. The custom of using silos for storing grain in Spain and France never became common, though several attempts were made to preserve large quantities of grain for several years, that the overproduction of one year might be kept until there were deficient harvests.
The subject of ensilaging green “roughage” material attracted attention in the United States soon after 1870. As early as 1875, Doctor Manly Miles, then connected with the Illinois Industrial University, was fairly successful in preserving the green tops of broom corn in an earthen silo. Interest in the subject of preserving green material in silos was widely aroused in America by the appearance of a book on ensilage, translated in 1878-9. The book was published in France in 1877, by M. Auguste Goffart.
When the practice of ensilaging green material for feeding animals was first introduced into the United States there was much discussion as to the construction of silos. Many advocated building them of stones, brick, or grout, though some were built of wood. As a rule, they were built either square or in the form of a parallelogram, in a few cases octagonal. Experience soon showed that the silage was preserved better in the wooden silo than in those constructed of other material. For this reason, and because the wooden silo is most cheaply constructed, wood is now in universal use for building them.
At first heavy frames were erected which were covered with two, three, and even four thicknesses of boards. Sometimes building paper was placed between the inner and outer boards. The octagon and the round silo soon supplanted those having square corners. As built, too often the walls could not be or were not fully ventilated. The thick walls remained more or less damp throughout the entire year or, if dried out when empty, lack of ventilation superinduced dry rot. Cases were not infrequent where silos were found to be practically useless without rebuilding in four or five years. Where everything was at its best, the frequent shrinking and swelling of the wood resulted finally in so destroying its elasticity that it did not return to its normal size when the silo was refilled. Since there was no means of tightening these silos the air soon entered them freely, which resulted in serious loss of fodder. By reason of the costliness and defects of stone and grout silos, and the failure in many cases of square-cornered wooden ones to preserve the material satisfactorily, and because of their perishable nature, much attention has been given to the shape and material of silos.
Fig. 130. The stave silo.
From all the evidence attainable, the conclusion is reached that the round, tall, stave silo is best. It is simple in construction, inexpensive as compared with most other kinds, and reasonably durable. The fact that it dries out fully during the summer, thereby destroying all germs of decay, coupled with the other fact that at any time it can be made tight by means of the hoops which serve to hold the staves in place, makes the round, stave silo par excellent. The staves should be two inches thick and from four to six inches wide, bevelled to suit the size of the structure. The hoops are usually of round galvanized iron one-half inch in diameter. They are placed about three feet apart, the spaces between the hoops being wider near the top than they are near the bottom. The hoops are made in sections of variable lengths; the ends of each section are furnished with lugs, that the hoop may be shortened and the silo tightened with ease. The illustration (Fig. 130) shows an emergency silo built of rough green hemlock plank unbevelled, hooped with “American woven wire fence.” It is 24 feet high, 12 feet in diameter, cost $35, and has a nominal capacity of 50 tons. A flat board roof serves to keep out the snow and most of the rain. It is placed in the open to test its durability. It has been in use one year, and so far it is entirely satisfactory, though the staves would be better if they had been beveled.
How long will this inexpensive silo last? That remains to be determined. Judging from other silos of similar construction which were erected several years ago, I judge it will last 15 or 20 years with slight repairs. When left thus exposed, will the silage freeze during the winter? In extremely cold weather in central New York, when the thermometer drops to 10° or 15° below zero, the material at the top will freeze. If straw be spread over the silage to the depth of a few inches, it will prevent the escape of heat and freezing. A portion of the straw covering is thrown back out of the way, the silage wanted removed, and the covering returned. Such precaution is only necessary during a few of the coldest days.