Agronomy Journal 12(5): 175-182 (May 1920)
THE HISTORY OF THE SILO.1
Contribution from Office of Forage-Crop Investigations, Bureau of Plant
Industry, United States Department of Agriculture, Washington, D. C. Received
for publication February 27, 1920.
2 Numbers in parentheses refer to "Literature cited," p. 181.
The term "silo" is of ancient origin and means a grain pit (2).2
Hermetically sealed granaries either above or below ground, usually partly below and partly above, were in use in the dry Mediterranean countries long before the Christian era. Varro (4) states:
Some farmers have their granaries under ground like caverns, which they call silos as in Cappadocia and Thrace while hither in Spain in the vicinity of Carthage and at Osca pits are used for this purpose the bottoms of which are covered with straw; and they take care that neither moisture nor air has access to them except when they are opened for use, a wise precaution because where the air does not move the weevil will not hatch. Corn stored in this way is preserved for fifty years and millet indeed for more than a century.
The Egyptians built batteries of granaries separate from their other buildings. These were constructed of masonry above ground, were conical in shape, and were filled through an opening near the top (5). The grain was taken out through a door near the base. They were used to store grain in years of plenty for years of scarcity. The accumulation of carbon dioxid from partial fermentation of the grain effectually preserved the remainder. Varro (4, p. 172) says:
Those who store their grain in the pits which are called silos should not attempt to bring out the grain for some time after the silo has been opened because there is danger of suffocation in entering a recently opened silo.
Attempts to introduce this method of storing grain into France early in the nineteenth century copied from underground silos used in Spain failed because of the porous nature of the soil and seepage of water. This trouble was finally overcome by Doyere in 1855, who suggested building masonry silos lined with sheet iron. The Paris Omnibus Company constructed several silos, some underground and some above, after Doyere's plan which were in use for several years (5).
The practice of storing grain in underground pits was not confined to any one country or race of people. Some tribes of American Indians made use of this method to store their own corn while they were away on winter hunting expeditions (14). It was practiced more or less perhaps by all nomadic peoples.
There does not appear to be much connection, however, between this ancient method of storing grain and modern methods of ensiling forage. About all that the old method furnished was the name "silo" for the structure for the new process, from which were derived the terms silage and ensiling. As the secret of success of storing grain in silos was to have it dry when ensiled it does not seem probable that the preserving of green forage by the same method would be the natural outcome.
ENSILING GREEN FORAGE.
It is impossible to say when or where the practice of preserving green forage in pits or silos originated. The statement has been made many times that the process was known and practiced by the Romans. Not much evidence is apparent to substantiate this statement. Cato (4, p. 43) does say:
As long as they are available feed green leaves of elm, poplar, oak and fig to your cattle and sheep.
Store leaves also to be fed to the sheep before they have withered.
As the first reference in modern times to the matte of storing green forage for cattle, that of Prof. John Symonds (11) of the University of Cambridge in 1786, was made from observations in Italy of the process of preserving the leaves of trees in casks and pits, it seems highly probable that the practice as far as that class of forage is concerned comes down from the time of the Romans. A French correspondent to The American Farmer (13) in 1875, referring to the preserving of green forage, states:
There is nothing positively new in the idea. Since time immemorial vine leaves have been preserved in a green state in the district of Lyons and which has made the reputation of the famous Mt. Dore cheese.
If it had been customary for the Roman farmers to ensile green grains and other forages it seems probable that some of the agricultural writers of the time would have mentioned it. Their descriptions, however, with the exception noted above, deal with the storing of dry seeds in silos and not with green forages.
No matter whether the ancients ensiled green forages or not, the modern practice traces directly to the process of making sour hay in Germany and Hungary. This method was called to the attention of English-speaking farmers in 1843 by Prof. J. F. W. Johnston (6). It consisted of storing green grass, clover, or vetches in pits 12 feet square and 12 feet deep. Salt at the rate of 1 pound to each hundred-weight of green grass was added and the material was thoroly tramped by five or six men. After the pit was filled it was covered with boards and on these was placed a foot and a half of earth. Each pit held about 5 tons of fresh grass. It was found later that salting was unnecessary.
The similarity in the methods of making sauerkraut and silage has frequently led to the suggestion that ensiling green forages was the direct application of that well-known method of preserving cabbage. There is some basis for the belief. Sauerkraut-making was an older process than ensiling, judging from available historical data, and was commonly practiced in the countries where the method of making sour hay originated. Murray's New English Dictionary, defining the word sauerkraut, gives the following quotation under date of 1633 from Hart's Diet of the Diseased:
They pickle it (cabbage) up in all high Germany with salt and barberies and so keepe it all the yeere, being commonly the first dish you have served in at table which they call their sawerkraut.
The fact that the Germans first used salt in making their sour hay also lends strength to this suggestion.
The method of making sour fodder was described by a correspondent to the American Agriculturist (1) in 1873 from Albrechtsfeld, Hungary. Instead of using pits, it was customary there to dig trenches 12 feet wide at the top, 6 feet wide at the bottom, 12 feet deep, and 10 to 20 rods long. The process of filling and covering was similar to that described above. He stated that sour fodder could be stored for a few years without injury. Neither of these descriptions seems to have created much interest in the subject at the time it was published. Some French farmers tried the method, but for the same cause which resulted in the failure of the first underground grain pits in France, water seepage, the practice was abandoned.
The first recorded attempt to ensile green maize was made in 1861 by Herr Adolph Reihlen (15), a sugar manufacturer, near Stuttgardt, Germany. Herr Reihlen had previously traveled in America and had taken back seed of maize which he was growing largely for soiling purposes. He was undoubtedly familiar with the German method of making sour hay and had adapted the method to the storing of beet tops and beet pulp, both of which are easily preserved as silage. As early frosts often killed the maize crop, Herr Reihien tried storing it in trenches. He was so well pleased with the experiment that he gave his experience in a letter dated April, 1862, which was published in the Würtemberg Wochenblatt. This was followed by another letter by the same gentleman dated September 23, 1865, and published in the same paper. These letters were translated into French by M. Vilmorin-Andrieux and published in 1870 in the Journal d'Agriculture Pratique. At the time M. Vilmorin-Andrieux prepared his report Herr Reihien had increased his acreage of maize until he filled silos 15 feet wide at the top and slightly narrower at the bottom, 10 feet deep, and with an aggregate length of over three-fourths of a mile.
It is also of historic interest to note that Count Roederer of BoisRoussel in the Department of the Orne in 1867 began to preserve chopped green maize mixed with cut straw in silos (5, p. 136). This method was described in a letter dated June 18, 1870, published in the journal d'Agriculture Progressive the following week. The purpose of this experiment was to render the straw palatable as well as to preserve the green maize. M. Piret, farm manager for A. Houette at Bleneau, Belgium, in 1868 successfully experimented with the ensiling of chopped maize. He constructed in 1870 two pits of masonry. "They were found equally serviceable to those below ground" (12).
The publication of these articles in the French agricultural press in 1870, together with a disastrous drouth which prevailed that year thruout France and ruined the hay crop, caused widespread interest to be taken in the subject. M. Moreul of La Grignonniere in 1870 built an aboveground silo of masonry and filled it with unchopped but salted maize (9). His success induced M. Crevat in 1872 to construct three pit silos 26 feet by 10 feet at the top, 22 feet by 6.5 feet at the bottom, and 6. feet deep. A number of other attempts were made to ensile forage besides these which are here mentioned. Reports of experiences with this process kept appearing from time to time in the agricultural press. Another drouth in 1874 brought this subject prominently before the French farmers. The French Agricultural Society offered a prize that year to be awarded in 1876 for the best essay on the subject, "Preserving Green Forage." This action resulted in a great many literary efforts on the part of those who had tried the ensiling method. M. Goffart (3), a gentleman farmer of Burtin in Sologne, was one of the ablest of these writers. He had had considerable experience with the German system of making "brown hay" and had grown maize for forage for a number of years. He built four silos in 1852 hollowed out of the ground and plastered with Portland cement. He did not claim success for his method, however, until 1873. His earliest silos were too small to be practicable, each holding only about 2 cubic yards. They were used to store cut and mixed straw and maize for immediate feeding. They prolonged his period of feeding green corn fodder three or four weeks but did not effectually preserve the fodder. Goffart states:
In 1873, I had a real success, due mainly to accident . . . . Until this time I had hardly believed that the preservation of green maize for a long time was possible and I had very little confidence.
As Goffart had at that time the benefit of the successful experience of Herr Reihien, Count Roederer, M. Piret, and M. Moreul in preserving green maize, he can hardly be credited with being the originator of the process. His comprehensive experiments, his useful writings, and his frequent lectures before agricultural societies, however, well earned the decoration of Legion of Honor which he received in 1876 and the popular esteem in which he has been held in America as the "Father of Ensilage."
THE SILO IN AMERICA.
The introduction of the silo in America was due directly to the publicity given the subject in France.
The first appearance of a description of the French process of preserving green forage appears to have been in a series of letters from a French correspondent to the American Farmer published in Baltimore, Md. These letters were dated Paris and signed F. C. They ran through a number of years. This correspondent referred to the matter in a letter in the issue of October, 1874. In the January, 1875, issue he wrote:
Quite a revolution is taking place in the agriculture of the south of France by the cultivation of maize for green fodder and its preservation in a green state chopped and mixed with straw in trenches for winter consumption.
The subject was referred to again in subsequent letters. It was these, accounts which induced Francis Morris, of Oakland Manor, Md., to try the method in 1876 (10).
In the American Agriculturist of June, 1875, was an illustrated article entitled "Curing Green Fodder" which was translated from the Journal d'Agriculture Pratique. The terms silo was used in this article, probably for the first time in an English publication. In England the terms trenching, pitting, and potting were used. The experiences of M. Piret and M. Goffart were given. Practically everything connected with the French method was given in this article. This information was restated many times during the next five years. A more complete résumé of the subject was published in 1876 in the Annual Report of the United States Commissioner of Agriculture for 1875 (15). This was similar to the article in the American Agriculturist, being copied from the same French journal.
The Cultivator and Country Gentleman in its issue of October 21, 1875, had a communication signed B. F. J. (probably B. F. Johnson), Champaign County, Ill., from which is quoted the following:
Prof. Miles of the Illinois Industrial University has made pretty liberal experiments in the ensilage of maize and broom corn seed in the course of this autumn, the outcome of which will be given to the public as soon as the success or want of it in the undertaking has been determined .... To ensilage is to bury in silo or pits.
This communication is of special interest not only because it records the first American effort to preserve green corn but it also introduces the word "ensilage" into our language. Prof. Manly Miles in the issue of October 5, 1876, of the same paper gave a summary of the experiences of farmers in Europe with the process of ensiling and also of the results of his own experiments. The following is quoted from this letter:
Last season at Champaign, Ill., experiments on a small scale were made under my direction in the ensilage of corn stalks and broom corn seed with results that were on the whole satisfactory. Two pits 12 feet long, 6 feet wide, and about 8 inches below the surface of the soil were filled with cut corn stalks of a late variety and the piles carried up as high as the stalks could readily be made to keep their place. A covering of straw about 4 inches thick was then put over the pile and about 6 to 8 inches of earth added. After two or three weeks when the pile had settled an additional layer of earth about 8 inches in thickness was added. The stalks were cut by hand with a very inferior straw cutter.
Professor Miles went on to state that one of the pits of corn stalks was opened in December and that there was a layer of rotted material about 3 inches thick. The second pit was opened March 13, 1876, and considerably more had decayed. Below this decayed layer the silage had kept perfectly. Similar results were obtained in the case of the broom corn seed. Professor Miles suggested that the term ensilage be adopted to designate the method as there was no English equivalent.
Francis Morris, of Oakland Manor, near Ellicott City, Maryland, built a silo in 1876 and filled it with corn. This silo was a trench 4 feet wide, 10 feet deep, and 24 feet long. Mr. Morris became a very enthusiastic advocate of the silo and his experiences were given in a number of farm papers. Mr. J. B. Brown, of New York, translated the book "Ensilage of Maize" of A. Goffart. This was published in 1879 and distributed largely as an advertisement of an implement company of which Mr. Brown was president. This little book created a great deal of interest and Goffart was heralded as the "Father of Ensilage." From that time until the present, books, bulletins, and articles in the agricultural press on the subject "silos and silage"—much of it controversial—have appeared so frequently that the literature is too voluminous to need special enumeration. For the first 20 years after its introduction, silo‑building was a haphazard proposition. Each farmer tried his own individual ideas. Some of these were good, others were costly experiences to the builders. On the whole many valuable data were gained during this experimental stage. It was soon found that with air-tight walls all of the spoiled silage was at the top. This led to building the silos above ground and taller. With the taller silos weighting on the top of the silage was unnecessary. There was also a big saving in labor of tramping the cut material at filling time.
In 1891, Prof. F. H. King, of the Wisconsin Agricultural Experiment Station, began a study of the whole subject of silo construction and ensiling. This study covered a number of years in which he personally inspected over 200 silos. He was aided by quite a mass of data which had been collected at other experiment stations. The publication of Professor King's researches marked a new era in silo construction (7, 8). A few cylindrical silos had been constructed before that time, but King's description of the details of construction were so clear that the Wisconsin silo became for a decade the most popular type built. The pits, trenches, and low, squatty, rectangular structures gave way to the tall, cylindrical silos. The Wisconsin silo is no longer practicable owing to the comparative high cost of construction and early decay. But the principles of construction, the weights and lateral pressure of silage at different depths, and the size of silo to build for a given number of animals as worked out by King and published in several reports and bulletins of the Wisconsin Agricultural Experiment Station are used more today than when they were first written. King's silage tables are classics. No man has done more than he to make the silo a success.
Also the following unsigned articles: