A modern John Deere 8110 Farm Tractor plowing a field using a chisel plow.

The most common use of the term is for the vehicles used on farms. The farm tractor is used for pulling or pushing agricultural machinery or trailers, for plowing, tilling, disking, harrowing, planting, and similar tasks. Charles City, Iowa is the birthplace of the farm tractor in the early 1900's by the Hart-Parr Company,^{[citation needed]} Later sold to White Tractor.

The first powered farm implements in the early 1800s were portable engines – steam engines on wheels that could be used to drive mechanical farm machinery by way of a flexible belt. Around 1850, the first traction engines were developed from these, and were widely adopted for agricultural use. Where soil conditions permitted, like the US, steam tractors were used to direct-haul ploughs, but in the UK, ploughing engines were used for cable-hauled ploughing instead. Steam-powered agricultural engines remained in use well into the 20th century, until reliable internal combustion engines had been developed. ^[3]

In 1892, John Froelich built the first practical gasoline-powered tractor in Clayton County, Iowa. Only two were sold, and it was not until 1911, when the Twin City Traction Engine Company developed the design, that it became successful.

In Britain, the first recorded tractor sale was the oil-burning Hornsby-Ackroyd Patent Safety Oil Traction engine, in 1897. However, the first commercially successful design was Dan Albone's three-wheel Ivel tractor of 1902. In 1908, Saundersons of Bedford introduced a four-wheel design, and went on to become the largest tractor manufacturer outside the USA.

While unpopular at first, these gasoline-powered machines began to catch on in the 1910s when they became smaller and more affordable. Henry Ford introduced the Fordson, the first mass-produced tractor in 1917. They were built in the U.S., Ireland, England and Russia and by 1923, Fordson had 77% of the U.S. market. The Fordson dispensed with a frame, using the strength of the engine block to hold the machine together. By the 1920s, tractors with a gasoline-powered internal combustion engine had become the norm.

The classic farm tractor is a simple open vehicle, with two very large driving wheels on an axle below and slightly behind a single seat (the seat and steering wheel consequently are in the center), and the engine in front of the driver, with two steerable wheels below the engine compartment. This basic design has remained unchanged for a number of years, but enclosed cabs are fitted on almost all modern models, for reasons of operator safety and comfort.

Originally, plows and other equipment were connected via a draw-bar, or a proprietary connecting system; prior to Harry Ferguson patenting the three-point hitch. Recently, Bobcat's patent on its front loader connection has expired; and compact tractors are now being outfitted with quick-connect attachments for their front-end loaders.

A small red tractor towing a cargo cart

Modern farm tractors usually have five foot-pedals for the operator on the floor of the tractor. The pedal on the left is the clutch. The operator presses on this pedal to disengage the transmission for either shifting gears or stopping the tractor. Two of the pedals on the right are the brakes. The left brake pedal stops the left rear wheel and the right brake pedal does the same with the right side. This independent left and right wheel braking augments the steering of the tractor when only the two rear wheels are driven. This is usually done when it is necessary to make a tight turn. The split brake pedal is also used in mud or soft dirt to control a tire that spins due to loss of traction. The operator presses both pedals together to stop the tractor. For tractors with additional front-wheel drive, this operation often engages the 4-wheel locking differential to help stop the tractor when travelling at road speeds.

A fifth pedal just in front of the seat operates the rear differential lock (diff lock) which prevents wheelslip. The differential allows the outside wheel to travel faster than the inside one during a turn. However, in traction conditions on a soft surface the same mechanism could allow one wheel to slip, thus preventing traction to the other wheel. The diff lock overrides this, causing both wheels to supply equal traction. Care must be taken to unlock the differential, usually by hitting the pedal a second time, before turning, since the tractor cannot perform a turn with the diff lock engaged.

Modern farm tractors employ large diesel engines, which range in power output from 18 to 575 horsepower (15 to 480 kW). Tractors can be generally classified as two-wheel drive, two-wheel drive with front wheel assist, four-wheel drive (often with articulated steering), or track tractors (with either two or four powered rubber tracks). Variations of the classic style include the diminutive lawn tractors and their more capable and ruggedly constructed cousins, garden tractors, that range from about 10 to 25 horsepower (7.5-18.6 kW) and are used for smaller farm tasks and mowing grass and landscaping. Their size—especially with modern tractors—and the slower speeds are reasons motorists are urged to use caution when encountering a tractor on the roads.

A PTO shaft connected to a tractor.

Most tractors have a means to transfer power to another machine such as a baler, slasher or mower. Early tractors used belts wrapped around a flywheel to power stationary equipment. Modern tractors use a power take-off (PTO) shaft to provide rotary power to machinery that may be stationary or pulled. Almost all modern tractors can also provide external hydraulic fluid and electrical power.

Most farm tractors use a manual transmission. They have several sets of gear ratios divided into speeds. In order to change the ratio, it is usually necessary to stop the tractor. Between them they provide a range of speeds from less than one mile per hour suitable for working the land, up to about 25 miles per hour (40 km/h) for road use. Furthermore it is usually not necessary to change gear in order to reverse, one simply selects a lever. Older tractors usually require that the operator depress the clutch in order to shift between gears (a limitation of straight-cut gears in the gearbox), but many modern tractors have eliminated this requirement with the introduction of technologies such as power shifting in the 1960s and more modern continuously variable transmissions. This allows the operator more and easier control over working speed than the throttle alone could provide.

The classic Row Crop tractor (an Allis-Chalmers WD). Note the absence of any rollover protection system.

Agriculture in the United States is one of the most hazardous industries, only surpassed by mining and construction. No other farm machine is so identified with the hazards of production agriculture as the tractor.^[4] Tractor related injuries account for approximately 32% of the fatalities and 6% of the non-fatal injuries in agriculture. Over 50% is attributed to tractor overturns.^[5]

The roll over protection structure(ROPS) and seat belt, when worn, are the two most important safety devices to protect operators from death during tractor overturns.^[6]

Modern tractors have rollover protecti