ENSILAGE, the process of preserving green crops in a suc culent condition in a silo, i.e., a pit, a stack or a tall cylindrical tower above ground (from Gr. atpas, Lat. sirus, a pit for holding grain). The fodder which is the result is called silage.
The method seems to have been practised in Central Europe (its principles are similar to those involved in the making of sauerkraut) when special attention was first directed to it by Auguste Goffart, a French agriculturist, who in 1877 published a work (Manuel de la culture et de l'ensilage des mais et autres fourrages verts) detailing the experiences of many years in pre serving green crops in silos. A translation of Goffart's book by J. B. Brown was published in New York in 1879. This attracted considerable attention in the United States, where the practice was then in its infancy. With the development of the tower silo and the investigations of S. M. Babcock, of Wisconsin, and others the practice has become the main source of succulent fodder for winter feeding in America and in other parts of the world where labour is costly. In the United Kingdom, following the disastrously wet year, 1879, and investigations by George Fry, of Chobham, the practice was widely tried, but under the conditions then prevailing proved unsuccessful. It was revived by George Jaques, of Tivetshall, Norfolk, who, in 1912, introduced the tall America tower silo, and aided by investigations at Cambridge and elsewhere the practice shows slow but steady growth.
The most suitable crops for silage in Britain are mixtures con taining pulse and cereals and, in suitable localities, maize. In warmer climates maize is used almost exclusively. Meadow grass and sown grass mixtures can ad vantageously be made into silage when weather conditions prevent hay-making, but cruciferous crops (mustard, turnip, cabbage, etc.) are not suitable. On heavy soils and in districts of consid erable rainfall the best mixture is composed largely of beans, with a light seeding of tares or peas and oats of a straw-produc ing variety. This mixture pro duces heavy crops which, owing to the robust stems of the beans, stand well, smother weeds and are easy to harvest. On light soils in a dry district beans are unsuit able. In this case a mixture of oats and tares alone is more suit able, but again the proportion of tares must not be too large lest the climbing stems and weight of the tares cause the whole crop to be "laid" on the ground. Maize can only be grown satisfactorily on warm soils in early districts, and even then care must be taken to use suitable varieties which ripen early. The varieties commonly grown in Britain for green soiling are unsuitable because they do not mature early enough. At the time of ensiling maize should be so mature that the fully formed cobs contain grains which are firm and glazed. The most suitable varieties are Jaune Gros du Domaine, a French variety, and to a lesser extent Salzer's North Dakota and Longfellow, which are American varieties.
It can be fed, if required, immediately it is made, or in times of plenty it can be stored in the silo for indefinite periods with out depreciation, provided air is excluded. In silage stacks and clamps air cannot be completely excluded, and therefore continu ous wastage is occasioned by storage. Digestibility experiments have shown that well made silage possesses a feeding value in accordance with that suggested by its chemical analysis, and feed ing experiments have confirmed this fact. In one series of ex periments by H. E. Woodman at Cambridge, in which parts of the same oat and tare crop cut at the same time, were fed firstly as green crop, secondly as hay, and thirdly as silage, it was shown that the food value of the silage was equal to the green crop and greater than that of the hay.
Stack silage by reason of the large surface exposed to the air is liable to continuous moulding and consequently to considerable wastage from decay. For this reason it is not suitable for general adoption in ordinary farm practice. But it involves no capital outlay and can be brought into play at a moment's notice. It is therefore a useful method of saving hay crops in seasons when hay-making is rendered impossible or difficult by continuous rain. Clamp silage is liable to similar though smaller losses. It, too, involves little time or outlay in preparing the clamp. The site for the clamp must be carefully chosen lest the clamp be comes full of water in winter. This method may be adopted in regular farm practice, as, for example, with maize in South Africa, where subsoil water is not troublesome, or less frequently in Britain with mixed crops. Like stack silage it may also be used to save hay crops in adverse seasons.
In general it may be said that silage making lends itself to in dustrial conditions of management more than most farming processes, and for this reason the practice is likely to secure a permanent place in agriculture.
Next to maize the sorghums, both saccharine and non-saccharine, constitute the most satisfactory silage crop. Being somewhat more drought resistant than maize, they are generally used where the rainfall is rather limited and also in some of the hot, irrigated districts where maize does not thrive. In feeding value good sorghum silage is nearly equal to maize silage. In recent years sunflowers have received considerable attention as a silage crop especially in the extreme north where the seasons are too short and too cool for maize. The silage is much less palatable but after the animals become accustomed to the flavour they eat consider able quantities of it and seem to do well. Legumes alone have not proved altogether satisfactory as a silage. In some cases they have yielded a palatable product ; in others a silage that was rank flavoured and not relished by cattle. One reason for this failure is the higher water content. For this reason such crops should be allowed to become as mature as practicable before ensiling, or if cut earlier, should be allowed partially to cure. Mixtures of maize and legumes make excellent silage. Small grains, peas and oats mixed, beet tops, cane tops, rape, etc., are ensiled in a limited way with a fair degree of success.
In the United States the stack silage is used chiefly in putting up refuse from pea canneries. This method of preserving fodder in a succulent state has also been employed occasionally with maize and sweet clover. The pit or trench silos are employed chiefly in those regions where the rainfall is rather limited. In locating such silos it is essential that they be placed in firm, dry and well-drained soil, otherwise there it *danger of spoilage through accumulation of water in the pit. The advantages of the pit and trench silos are that they are cheap, easily constructed, will not blow down, and do not require the silage blower in filling.
The preservation of forage as silage possesses a number of ad vantages, especially with coarse plants like maize and sorghum. Among these advantages are : ( 1) Silage preservation saves all of the forage in edible form. The loss both in preserving and feeding is much smaller than with dry fodder. (2) Silage is more palatable than dry fodder and animals will eat a larger quantity. (3) Silage preservation is not dependent upon favourable weather. conditions. (4) Silage requires less space for storage than the equivalent amount of hay or f odder. (5) The cost of the ration is materially reduced by feeding ensilage to all classes of live stock.