A baler is a machine that compresses and binds a volume of material into a round or rectangular shape for transportation and storage. In farm applications, the baler processes cut vegetation or hay usually intended for animal feed and is towed behind a tractor. In industrial applications, a stationary baler is used to compress and bind materials such as paper and cardboard in preparation for recycling.
Cut vegetation such as alfalfa, clover, or hay is chopped and left in the field in a narrow strip known as a windrow. A tractor pulling the baler moves along the windrow, where a row of teeth rakes the cut material up from the ground. The interior mechanism keeps the feed under pressure to compress it and continues adding material until the bale is the desired size. The bale is wrapped with twine or wire to secure it.
Different farm balers can produce various size and shape bales. Smaller rectangular bales are suitable for more modest, less-mechanized farm operations. They are more easily handled, weighing only about 50 pounds. Sizable rectangular or round bales are produced by large-scale commercial operations. These bales can weigh as much as a ton and require specialized heavy equipment to transport them. In the case of small bales, the baler either drops the bales on the ground to be picked up later or uses an ejector to throw the bale into an open trailer towed behind the baler. Large heavy bales are left in the field for later pickup.
Power for a farm baler comes from the tractor that pulls it. Using a power takeoff, power from the tractor is diverted to the baling machinery. The horsepower of the tractor provides sufficient force for all the steps performed by the bailing equipment.
A round baler is often used for the production of silage, i.e., animal feed that is cut and baled while still green. The baled material is sealed inside plastic wrapping and allowed to ferment. This fermented feed provides better nutrition for livestock than dried hay during seasons when there is no harvest.
Industrial balers processing waste materials for recycling can be used alone or as part of an automated process that shreds or segregates materials before baling. A variation is called a baling press, which uses a large plate to flatten the material and then binds it into a bale. A vertical unit is top-loading and can be intended to produce only one bale before requiring manual unloading. A horizontal unit loads from one side and produces a finished bale on the other. Most industrial balers are powered by electricity.