thumb|A [[cotton picker at work. The first successful models were introduced in the mid-1940s and each could do the work of 50 hand pickers.]]
Mechanised agriculture or agricultural mechanisation is the use of machinery and equipment, ranging from simple and basic hand tools to more sophisticated, motorised equipment and machinery, to perform agricultural operations. In modern times, powered machinery has replaced many farm task formerly carried out by manual labour or by working animals such as oxen, horses and mules.
The entire history of agriculture contains many examples of the use of tools, such as the hoe and the plough. The ongoing integration of machines since the Industrial Revolution has allowed farming to become much less labour-intensive.
Agricultural mechanisation is part of this technological evolution of agricultural automation. It can be summarised as a progressive move from manual tools to animal traction, to motorised mechanization, to digital equipment and finally, to robotics with artificial intelligence (AI). These advances can raise productivity and allow for more careful crop, livestock, aquaculture and forestry management; provide better working conditions; improve incomes; reduce the workload of farming; and generate new rural entrepreneurial opportunities.
Since the beginning of agriculture threshing was done by hand with a flail, requiring a great deal of labour. The threshing machine, which was invented in 1794 but not widely used for several more decades, simplified the operation and allowed the use of animal power. Before the invention of the grain cradle (ca. 1790) an able bodied labourer could reap about one quarter acre of wheat in a day using a sickle. It was estimated that each of Cyrus McCormick's horse-pulled reapers (ca. 1830s) freed up five men for military service in the US Civil War. Later innovations included raking and binding machines. By 1890 two men and two horses could cut, rake and bind 20 acres of wheat per day.
In the 1880s the reaper and threshing machine were combined into the combine harvester. These machines required large teams of horses or mules to pull. Steam power was applied to threshing machines in the late 19th century. There were steam engines that moved around on wheels under their own power for supplying temporary power to stationary threshing machines. These were called road engines, and Henry Ford seeing one as a boy was inspired to build an automobile.
With internal combustion came the first modern tractors in the early 1900s, becoming more popular after the Fordson tractor (ca. 1917). At first reapers and combine harvesters were pulled by teams of horses or tractors, but in the 1930s self powered combines were developed.
Advertising for motorised equipment in farm journals during this era did its best to compete against horse-drawn methods with economic arguments, extolling common themes such as that a tractor "eats only when it works", that one tractor could replace many horses, and that mechanisation could allow one man to get more work done per day than he ever had before. The horse population in the US began to decline in the 1920s after the conversion of agriculture and transportation to internal combustion. Peak tractor sales in the US were around 1950. In addition to saving labour, this freed up much land previously used for supporting draft animals. The greatest period of growth in agricultural productivity in the US was from the 1940s to the 1970s, during which time agriculture was benefiting from internal combustion powered tractors and combine harvesters, chemical fertilisers and the green revolution.
Although US farmers of corn, wheat, soy, and other commodity crops had replaced most of their workers with harvesting machines and combines by the 1950s enabling them to efficiently cut and gather grains, growers of produce continued to rely on human pickers to avoid the bruising of the product in order to maintain the blemish-free appearance demanded by customers. The continuous supply of undocumented workers from Latin America that harvest the crops for low wages further suppressed the need for mechanisation. As the number of undocumented workers has continued to decline since reaching its peak in 2007 due to increased border patrols and an improving Mexican economy, the industry is increasing the use of mechanisation.
Extensive adoption started in the United States of America, where tractors replaced about 24 million draught animals between 1910 and 1960 and became the main source of farm power. United Kingdom first started using tractors in the 1930s, but agricultural transformation in Japan and some European countries (Denmark, France, Germany, Spain and former Yugoslavia) did not take place until about 1955. Thereafter, the adoption of motorised mechanization took place very quickly, completely superseding animal traction. Using tractors as farm power enabled, and even triggered, innovations in other agricultural machinery and equipment that greatly eased the toil associated with agriculture and allowed farmers to carry out tasks more quickly. At a later stage, motorised machinery also increased in many Asian and Latin American countries. A study in 11 countries proves this low level of mechanisation in the region, finding that only 18 per cent of the sampled households have access to tractor-powered appliances. The remaining ones make use of either simple hand-held tools (48 per cent) or animal-powered equipment (33 per cent).
If rising wages and labour scarcities drive the adoption of automation then it is not likely to create unemployment. Asparagus is a difficult crop to harvest since each spear matures at a different speed making it difficult to achieve a uniform harvest. A prototype asparagus harvesting machineusing a light-beam sensor to identify the taller spearsis expected to be available for commercial use.
As of 2014, prototype chili pepper harvesters are being tested by New Mexico State University. The New Mexico green chile crop is currently hand-picked entirely by field workers as chili pods tend to bruise easily. The first commercial application commenced in 2015. The equipment is expected to increase yield per acre and help to offset a sharp decline in acreage planted due to the lack of available labour and drought conditions.
As of 2010, approximately 10% of the processing orange acreage in Florida is harvested mechanically, mainly with citrus canopy shaker machines. Mechanization has progressed slowly due to the uncertainty of future economic benefits due to competition from Brazil and the transitory damage to orange trees when they are harvested. Fresh peaches destined for direct customer sales must still be hand-picked.
As of 2007, mechanised harvesting of raisins is at 45%; however the rate has slowed due to high raisin demand and prices making the conversion away from hand labour less urgent. A new strain of grape developed by the USDA that drys on the vine and is easily harvested mechanically is expected to reduce the demand for labour.
Strawberries are a high cost-high value crop with the economics supporting mechanisation. In 2005, picking and hauling costs were estimated at $594 per ton or 51% of the total grower cost. However, the delicate nature of fruit make it an unlikely candidate for mechanisation in the near future. A new strawberry harvester made by Agrobot that will harvest strawberries on raised, hydroponic beds using 60 robotic arms is expected to be released in 2016. As of 2010, 95% of the US processed tomato crop is produced in California. To withstand the rigour of the machines, new crop varieties were bred to match the automated pickers. UC Davis Professor G.C. Hanna propagated a thick-skinned tomato called VF-145. But even still, millions were damaged with impact cracks and university breeders produced a tougher and juiceless "square round" tomato. Small farms were of insufficient size to obtain financing to purchase the equipment and within 10 years, 85% of the state's 4,000 cannery tomato farmers were out of the business. This led to a concentrated tomato industry in California that "now packed 85% of the nation’s tomato products". The monoculture fields fostered rapid pest growth, requiring the use of "more than four million pounds of pesticides each year" which greatly affected the health of the soil, the farm workers, and possibly the customers.