Throughout agriculture's evolution, machinery and technologies have been devised and revised to increase farm production and decrease farm labor. Those who work the soil know it requires different treatment at each stage of the growing cycle. Hence, various machines have been developed for the differing tasks. The machines are used toward a common purpose: bringing forth a harvest from dirt and seed.
Providing the power: the tractor
Central to all modern farming is the tractor. The steam engine that ushered in the Industrial Revolution of the 1800s likewise changed farming forever. As populations grew and farm implements became larger, human labor and farm animals were not enough to cope with the increased demand. Following the initial steam-powered engines came today's self-propelled models that run on gasoline. Upgrades to the tractor most often are in response to improvements in the implements. The belt pulley, draw bar and power take-off, usually referred to as PTO, are all features developed for the driving, pulling and powering of attached agricultural machinery.
Preparing the Soil
Although several attachments break up and prepare soil for planting, the primary apparatus is the plow. Usually metallic in frame, the plow consists of one or more curved blades, known as mold boards, which can be set at varying degrees of depth. The mold boards cut into and turn over the soil: the vertical blades (called coulters) and the horizontal blades, or plowshares. Modern plows allow for adjustments in the length and width of coverage. Plowing uproots weeds and expels stones.
Planting the Seed
Originally dubbed "sowing machines, seed planters are able to plant multiple rows of seed at equal spacing and depth. Planters consist of sharpened discs that open and close furrows in which to drop the seeds. Gauge wheels ensure consistent depth, a metal point perfects the furrow, and a feeding tube helps deposit the seed. Lastly, specialized wheels turn to close the furrow.
Cultivating the Field
The cultivator functions similarly to the plow, except that it get s used once seed is planted and crops are growing. Cultivators possess teeth that straddle the plant rows, sifting and refining the surrounding soil. This task is essential so that minuscule spaces, known as macro-pores, can remain in the soil, affording room for water, oxygen and growing roots. Most modern cultivators cover three to five rows, although some models exceed 15 rows.
Harvesting the Crop
Combine harvesters take the stalk from the ground, remove grain from the stalk, and shake excess debris from the grain. This process of harvesting, threshing and cleaning gives the combine its name. The header, a set of scissor-like teeth, cuts the stalks, which are then pulled onto a pick-up reel that transfers them to the threshing drum. Here the stalks are subject to high-impact pounding as the grain is released and then sifted.