Silage

Silage is fermented, high-moisture stored fodder which can be fed to cattle, sheep and other such ruminants (cud-chewing animals) or used as a biofuel feedstock for anaerobic digesters. It is fermented and stored in a process called ensilage, ensiling or silaging, and is usually made from grass crops, including maize, sorghum or other cereals, using the entire green plant (not just the grain). Silage can be made from many field crops, and special terms may be used depending on type; oatlage for oats, haylage for alfalfa — but see below for the different British use of the term haylage.

Silage is made either by placing cut green vegetation in a silo or pit, by piling it in a large heap and compressing it down so as to leave as little oxygen as possible and then covering it with a plastic sheet, or by wrapping large round bales tightly in plastic film.

The crops suitable for ensilage are the ordinary grasses, clovers, alfalfa, vetches, oats, rye and maize; various weeds may also be stored in silos, notably spurrey such as Spergula arvensis. Silage must be made from plant material with a suitable moisture content: about 50% to 60% depending on the means of storage, the degree of compression, and the amount of water that will be lost in storage, but not exceeding 75%. Weather during harvest need not be as fair and dry as when harvesting for drying. For corn, harvest begins when the whole-plant moisture is at a suitable level, ideally a few days before it is ripe. For pasture-type crops, the grass is mowed and allowed to wilt for a day or so until the moisture content drops to a suitable level. Ideally the crop is mowed when in full flower, and deposited in the silo on the day of its cutting.

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