El arado es una herramienta de labranza utilizada en la agricultura para abrir surcos y remover el suelo antes de sembrar las semillas. Se puede considerar como la evolución del pico y de la azada. En un principio el arado era tirado por personas, luego por bueyes o mulas, y en algunas zonas por caballos, y actualmente también los tractores tiran de ellos. Arar aumenta la porosidad, lo que favorece el crecimiento de las plantas, aunque al remover el suelo se pierde agua por evaporación y algo de suelo por erosión, y las eventuales lluvias lavan los nutrientes y abonos que puedan haberse aplicado al suelo, generando pérdidas. El arado surgió posiblemente en Mesopotamia. El arado tradicional tirado por animales procede del arado romano, que consta de una esteva (para guiar) y reja (de hierro) que es la que rompe el terreno. El arado Rotherham fue construido en Inglaterra en 1730. Su forma triangular hizo más fácil tirar de él y se adaptó para ser tirado por caballos. Fue construido por el holandés Joseph Foljambe y marca el comienzo de su fabricación industrial.

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A plough (UK) or plow (US; both /ˈplaʊ/) is a tool or farm implement used in farming for initial cultivation of soil in preparation for sowing seed or planting to loosen or turn the soil. Ploughs are traditionally drawn by working animals such as horses or cattle, but in modern times may be drawn by tractors. A plough may be made of wood, iron, or steel frame with an attached blade or stick used to cut the earth. It has been a basic instrument for most of recorded history, although written references to the plough do not appear in English until c. 1100 at which point it is referenced frequently. The plough represents one of the major agricultural inventions in human history. The primary purpose of ploughing is to turn over the upper layer of the soil, bringing fresh nutrients to the surface, while burying weeds and the remains of previous crops and allowing them to break down. As the plough is drawn through the soil it creates long trenches of fertile soil called furrows. In modern use, a ploughed field is typically left to dry out, and is then harrowed before planting. Plowing and cultivating a soil homogenizes and modifies the upper 12 to 25 cm of the soil to form a plow layer. In many soils, the majority of fine plant feeder roots can be found in the topsoil or plow layer. Ploughs were initially human powered, but the process became considerably more efficient once animals were pressed into service. The first animal powered ploughs were undoubtedly pulled by oxen, and later in many areas by horses (generally draft horses) and mules, although various other animals have been used for this purpose. In industrialised countries, the first mechanical means of pulling a plough were steam-powered (ploughing engines or steam tractors), but these were gradually superseded by internal-combustion-powered tractors. Modern competitions take place for ploughing enthusiasts like the National Ploughing Championships in Ireland. Use of the plough has decreased in some areas, often those significantly threatened by soil damage and erosion, in favour of shallower ploughing and other less invasive conservation tillage techniques. Natural farming methods are emerging that do not involve any ploughing at all, unless an initial ploughing is necessary to break up hardpan on a new plot to be cultivated, so that the newly introduced soil life can penetrate and develop more quickly and deeply. By not ploughing, beneficial fungi and microbial life can develop that will eventually bring air into the soil, retain water and build up nutrients. A healthy soil full of active fungi and microbial life, combined with a diverse crop (making use of companion planting), suppresses weeds and pests naturally and retains rainwater. Thus the intensive use of water-, oil- and energy hungry irrigation, fertilizers and herbicides are avoided. Cultivated land becomes more fertile and productive over time, while tilled land tends to go down in productivity over time due to erosion and the removal of nutrients with every harvest. Proponents of permaculture claim that it is the only way of farming that can be maintained when fossil fuel runs out. On the other hand, the advantage of agricultural methods that require repeated ploughing are that they allow monocropping on a large scale at remote locations, using industrial machinery rather than human labor.

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