Cultivator

A cultivator is a farming tool for secondary tillage. One type consists of a frame with teeth, or shanks, that are dragged through the soil in a straight line. Another type uses rotating disks or teeth, like a rotary tiller (sometimes called a rotavator), to achieve a similar effect. Cultivators break up and loosen the soil. This is done either before planting to aerate the ground and create a smooth, loose seedbed, or after the crop has started growing to control weeds. By carefully disturbing the topsoil near the crop plants, they uproot weeds, bury their leaves to block photosynthesis, or both. Unlike a harrow, which churns the entire soil surface, a cultivator works in precise patterns that avoid damaging the crops while targeting the weeds.

Toothed cultivators look similar to chisel plows, but serve a different purpose. Cultivator teeth work near the surface, mainly for weed control, while chisel plow shanks dig deep to break up hardpan. Small, toothed cultivators pushed or pulled by one person are used in home gardens or small market gardens. Similarly sized rotary tillers combine the jobs of a harrow and a cultivator into one machine. Motorized cultivators can be self-propelled or attached as an implement behind a two-wheel or four-wheel tractor. On two-wheel tractors, they are usually fixed rigidly and powered by the tractor’s transmission. On four-wheel tractors, they typically connect via a three-point hitch and run off a power take-off. Drawbar hookup is also still common worldwide. Draft animals are sometimes still used for cultivators, especially in developing nations, though this is rare in industrialized economies.

**History**

The basic idea of scratching the soil to control weeds is ancient, done with hoes or plows for millennia before larger equipment was developed to reduce labor and speed the work. Grouping several hoes together and using draft animals to pull them led to harrows, which, though newer than the hoe, are still very old. During the eighteenth and nineteenth centuries, as the Industrial Revolution progressed, many new cultivator designs appeared. These were pulled by draft animals like horses, mules, or oxen, or pushed or pulled by people, depending on need and cost.

The powered rotary hoe was invented by Arthur Clifford Howard. In 1912, he began experimenting with rotary tillage on his father’s farm in Gilgandra, New South Wales, Australia. Using his father’s steam tractor engine for power, he found that soil could be tilled mechanically without the soil-packing that occurred with normal plowing. His early designs threw soil sideways, but he improved the machine by creating an L-shaped blade mounted on widely spaced flanges on a small-diameter rotor. With fellow apprentice Everard McCleary, he started a company to build his machine, but World War I interrupted their plans. In 1919, Howard returned to Australia and resumed his work, patenting a design in 1920 that featured five rotary hoe blades and an internal combustion engine. In March 1922, he formed Austral Auto Cultivators Pty Ltd, later known as Howard Auto Cultivators, based in Northmead, a suburb of Sydney, from 1927.

Meanwhile, in North America during the 1910s, tractors were becoming smaller, lighter, and more affordable, moving away from the huge traction engines. The Fordson tractor, in particular, made tractors practical and affordable for small and medium family farms for the first time. Cultivating was an afterthought in the Fordson’s design, since simply bringing motorized traction to that market was itself a milestone. This left room for others to improve motorized cultivating. Between 1915 and 1920, inventors and farm implement companies experimented with “motor cultivators”—modified horse-drawn shank-type cultivators with motors added for self-propulsion. These had limited market success. But by 1921, International Harvester combined motorized cultivating with other tractor tasks—tractive power and belt work—to create the Farmall, a general-purpose tractor designed for cultivating that essentially invented the category of row-crop tractors.

In Australia, by the 1930s, Howard struggled to meet growing worldwide demand for his machines. He traveled to the United Kingdom and founded Rotary Hoes Ltd in East Horndon, Essex, in July 1938. Branches later opened in the United States, South Africa, Germany, France, Italy, Spain, Brazil, Malaysia, Australia, and New Zealand. This company eventually became the holding company for Howard Rotavator Co. Ltd. The Howard Group was acquired by the Danish Thrige Agro Group in 1985, and in December 2000 it became part of Kongskilde Industries of Soroe, Denmark.

In modern commercial agriculture, the use of cultivators for weed control has greatly declined due to herbicides. However, herbicides are not always desirable—for example, in organic farming. When herbicidal weed control was first widely commercialized in the 1950s and 1960s, it fit the optimistic worldview of that era, in which sciences like chemistry were expected to usher in a new age.