This article focuses on the role of agriculture mechanization in the growth process in different fields. Many innovations in agricultural mechanization occurred in the middle of the 19th century. Agricultural mechanization is often exemplified by the development of the tractor. A key figure in the development of tractors was a Michigan farm boy who first became interested in technology when he saw a large steam traction engine. The adoption of the gasoline tractor was aided significantly by successful demonstrations and tests. The many 20th-century advancements in machinery to till soil, plant, remove weeds, and apply fertilizers and pesticides are too numerous to discuss here. However, at least harvesting equipment should be discussed because its mechanization trailed only tractors in importance. Cyrus McCormick’s reaper replaced human-powered cutting tools in small grains with a horse-drawn machine in the 19th century.


The Majority of All Men Who have ever lived have been bound to drudgery on the land. We are breaking away from that servitude." So begins a 1960 book on agricultural mechanization. At the start of the 20th century, a U.S. farmer fed about 2 1/2 people. Today, that farmer feeds 97 Americans and 32 living abroad. This revolution has released the rest of the population to pursue the intellectual, cultural, and social development that has resulted in our modern society. Agricultural mechanization, like manufacturing, can be viewed as an enabling technology that made possible the other advances of the 20th century.

Many innovations in agricultural mechanization occurred in the middle of the 19th century. Cyrus Mc-Cormick's reaper and the thresher first appeared in the 1830s. The steam engine and the steam plow were developed before the American Civil War. But, as Abraham Lincoln said about the steam plow, “To be successful, it must, all things considered, plow better than can be done by animal power.” The value of horses and mules on American farms exceeded the worth of all the machines and equipment, including the animal-powered equipment, past 1910. It took the further developments and engineering of the 20th century to make agricultural mechanization a success.

The Tractor’s Pull

Agricultural mechanization is often exemplified by the development of the tractor. By 1900, about 5,000 traction engines were being produced by 30 companies every year. These giants, operating at steam pressures of 150 to 200 pounds per square inch, often weighed more than 20 tons. But universal adoption of mechanical power depended upon the internal combustion engine, which was being applied to tractors and other uses at that time.

A key figure in the development of tractors was a Michigan farm boy who first became interested in technology when he saw a large steam traction engine. He started experimenting in 1900 and developed an experimental tractor in 1907. But Henry Ford suspended his tractor work to develop and produce the Model T. Finally, in 1916 the Fordson tractor was introduced. Being lightweight, mass- produced, and low-cost, it was a fierce competitor to the other tractors of its time. It eventually achieved 75 percent market share in the United States and 50 percent worldwide.

Some agricultural innovations are adopted quickly. For example, the FMC mobile green pea har- vester/sheller was essentially adopted in three years in the late 1950s because of its obvious superiority over stationary shelters. But the tractor is a universal tool used in widely differing regions, crops, and farms. The adoption rate varied, depending upon crop prices, the economy, and labor availability. For example, the Fordson was helped greatly by the labor shortage of World War I. But the number of tractors on U.S. farms showed a substantial upward trend for 50 years, starting in 1915.

A peak production e nof virtually 800,000 was reached in 1951. Now that the United States is fully tractorized, about 100,000 are sold annually.

The adoption of the gasoline tractor was aided significantly by successful demonstrations and tests. The 1908 public demonstrations in Winnipeg were particularly significant. Nebraska passed a tractor test law in 1919. Rather than hurting sales, the compulsory testing verified the manufacturers’ claims and showed the potential of certain models.

The tractor was continually refined during the rest of the 20th century to be more efficient, productive, and user- friendly. Contemporary tractors perform four times the work per gallon of fuel as the first Nebraska test subjects. The development of the nimble general-purpose tractor in the mid-1920s, led by International Harvester’s Farmall model, made horses completely obsolete, even for small jobs.

Unfortunately, the early tractors were not just user-unfriendly, they were harmful and dangerous. Older farmers’ hearing test results often show a distinctive notch around 4 kilohertz. The seats often amplified the accelerations of the rough terrain at the spine-damaging frequencies. Worst of all, many farmers lost their lives in tractor overturns. Today’s farmers are much safer if they wear their seat belts and follow proper operating procedures.


One example of the several areas in which the needs of tractor productivity, efficiency, and user-friendliness come together is the power transmission from the high-speed engine to the low-speed wheels. Conventional gear transmissions, somewhat similar to automobile manual transmissions, continue to be used. However, they may have as many as 44 speeds. In the late 1950s and early 1960s, on-the- go shifting without operator clutching become commercialized.

Infinitely variable hydrostatic transmissions soon followed, but their commercial popularity has been limited to harvesting machines and special-purpose tractors where the reduced efficiency can be tolerated. Hydromechanical transmissions appeared in the late 1990s to provide infinite speeds at higher efficiencies. The farmer now easily selects the travel speed for the best productivity, and the engine and transmission provide that speed at peak efficiency.

Tractors are expected to provide propulsion power across soft soils. Traction is frequently the limiting factor in performing a job. At the beginning of the 20th century, large steel wheels were used. Now a debate rages between large radial tires and rubber belt tracks.

There has been a substantial increase in tractor travel speeds, which has had a significant effect on the other equipment. Planters, tillage equipment, and other machinery must now perform satisfactorily at those speeds and their controllers must have sufficient dynamic response.

Reaping What’s Sown

The many 20th-century advancements in machinery to till soil, plant, remove weeds, and apply fertilizers and pesticides are too numerous to discuss here. But at least harvesting equipment should be discussed because its mechanization trailed only tractors in importance.

Cyrus McCormicks reaper replaced human-powered cutting tools in small grains with a horse-drawn machine in the 19 th century. During the 20th century, the rest of the operations, including threshing and separation, were blended into the modern “combine.” The productivity gains from many improvements have advanced grain harvesting from 10 kilograms per manhour to as high as 60,000 kg/man-hour today. The importance of these machines can be seen by the special World War II approval for Massy-Harris to build 500 combines to follow the ripening small grain crop from Texas to Canada in the Harvest Brigade.

The mechanization of harvesting other crops was also important. The corn picker was developed in the early 1900s and the hay baler in the 1930s. After much expense and effort, cotton harvesting was mechanized in the 1940s. But innovations continued to improve the productivity and quality of the job performed throughout the century. The heavy, summer labor of manually handling small rectangular bales was relieved by the development, in the 1970s, of the baler, which produces the large, cylindrical hay bales that now commonly dot the countryside.


Automation of The Field

Agricultural mechanization developments early in the 20th century were spurred by new restrictions limiting immigrants into the United States. A contemporary question is what will happen to those U.S. fruit and vegetable crops for which manual harvesting constitutes more than half the total labor requirement. Most harvesters of some commodities are illegal entrants to the country because the work is seasonal, rural, and unappealing to most U.S. residents.

Perhaps the future is indicated by the trend in tomatoes. The tomatoes processed for pastes and sauces are mechanically harvested. Fragile, fresh-market tomatoes are moving to Mexico, accelerated by the North American Free Trade Agreement.

Agricultural mechanization has always been a political-social issue. Increasing farm consolidation has made many farmers and farm employees redundant, and has decimated some rural towns. Some current commentators anticipate the complete automation of farms within the next couple of decades. They see dire consequences in unemployed labor.

But empirical data might contradict this pessimism. The U.S. economy has absorbed the labor released over the last century to generate a high standard of living. India is another, very different, demonstration. It is the world’s largest tractor producer and consumer, with almost 280,000 predicted for this year. Indian farmers feed almost one billion people (although a large number of them poorly) and export grain. Compare their situation to the few countries in Africa with more than 80 percent of the agricultural energy supplied by humans, and their problems with inadequate food supply.

While seed genetics, agronomic practices, and political stability are rightly credited, the contribution of appropriate agricultural mechanization to food security should not be forgotten. A detailed study of paired Indian villages found that the tractorized villages were able to produce more crops per year by having the needed power at critical times. Not only was the production increased, but so was hired labor use.

Mechanization has reduced labor in the developed countries, but has not eliminated it. A very popular attraction at the big Century of Progress Fair in Chicago in 1933 was the radio-controlled tractor. Flowever, its unmanned successors have not found commercial success.

But automation has had many achievements in improving machine performance. The self-leveling combine was an early example. Perhaps the most famous was the ingenious system patented by Harry S. Ferguson to control the depth of implements in the soil. Its hydromechanical servo kept a constant load on the tractor. His 1939 oral agreement with Henry Ford allowed Ford, who had left tractor manufacturing, to reclaim much of his lost market share. Unfortunately, the collaboration ended in a nasty and record-breaking lawsuit.

The last third of the 20th century was dominated by electronics automation rather than mechanical and hydromechanical. Bob Dickey and Jack Littlejohn formed DICKEY-john Corp. to manufacture a monitor to verify that individual seeds are being planted correctly. Subsequently, an entire agricultural electronics industry has developed to the extent that there is now difficulty in standardizing electronic communications among the many sensors, controllers, and actuators.

Power on The Farm

The inclusion of electronics brought the mechanical and agricultural engineers who dominated agricultural mechanization into contact with electrical engineers at the end of the century. But that was not the first time. An argument can be made that stationary farmstead mechanization was just as important as tractors and other mobile equipment. This was achieved during the 20th century by electrification of the barns, sheds, granaries, and greenhouses.

The first use of electricity was in the farmhouse, raising the rural standard of living. Electrification eased the burden of farm women who shared their urban sisters’ household workload in addition to often-unrecognized farm duties. But soon lights were also on in henhouses, increasing egg production. A study in Wisconsin showed that good farmstead lighting saved an hour per day by making work more productive.

One of the innovations aided by electrification was the milking machine. Imagine the labor that would be required to hand-milk the thousands of cows m some contemporary herds. Gustav de Laval, famous for his 92 Swedish patents and 37 founded companies, was a key contributor to the milking machine. However, despite also inventing the centrifugal separator and the steam turbine and being a Ph.D. in engineering, he died in poverty.

Even in 1919, only 1.9 percent of U.S. farms had electric power. By 1960, the coverage had increased to 97 percent. The peak effort came in 1949, when 707 miles of power lines were constructed every workday. Some greatly credit President Roosevelt’s 1935 executive order establishing the Rural Electrification Administration. Other political views say that electrification was already inevitable.


The first known farm installation of an electric motor was on an irrigation pump in 1898. At the start of the 20th century, irrigation was practiced on 16 million acres. Four times that amount of land is now irrigated using electric and internal combustion motors to drive pumps, with less dependence on gravity flow. Water and energy-use efficiencies have been increased by the development of various technologies using tubes, pipes, and low pressure.

The green circles in America’s heartland make center pivot irrigation technology vividly apparent. Frank Zybach sold his patent for the center pivot to Valmont in 1953. With one end of a pipe located at a well or other water source, the long pipe travels on wheels applying water, fertilizer, and pesticides around the circle.

Electricity at the farmstead has also permitted environmental controls for barns and greenhouses. These controls, developed throughout the century starting from simple fans, encourage peak productivity from animals and plants. For example, temperature, humidity, solar radiation, and artificially elevated C02 can be optimized for production of a specific vegetable.

With the mechanization of harvesting, a similar mechanization of storage and the processing of harvested crops was required in order to handle the huge volumes quickly. Engineers have developed sophisticated, productive systems for such operations as drying, cooling, and storage. Their tasks were greatly complicated by the fragility and quality-maintenance demands of some commodities.

Indeed, the whole processing and food engineering area could be viewed as a significant innovation of the 20th century. The 19th-century consumer had primarily local, in-season foods. Now all foods are always available, through canning, freezing, or refrigerated transportation.

All of the above achievements, and many more, depended heavily upon engineers in the 20th century. Although some technologies had their roots in the 19th century, it was not until the 20th that they were refined enough to be commercially successful. Mechanical engineers joined farmers and craftsmen with mechanical aptitude to perform the work that led to successful mechanization.


Future In The Present

It is difficult to predict the future. In 1960, a top tractor expert predicted nuclear or electric-powered tractors. Even his short-term prediction of higher- octane engines was wrong, as the industry immediately converted to diesel. However, extrapolations from the present remain the most reliable prediction method.

The area of the greatest contemporary excitement and growth is what goes by the poorly chosen term of “precision agriculture.” Mechanization has caused farmers to lose their ability to treat each animal or small area within a field individually. The record-keeping capability of computers allows that ability to be recovered.

Precision agriculture essentially came to animal agriculture in the 1960s. Computerized records of milk production and animal physical characteristics were used to select artificial insemination for individual cows to improve the next generation. Transponders were introduced in 1968 so each cow could receive the optimum feed from feeding machines.

Precision agriculture for plant agriculture started in the 1980s, but is just now receiving widespread commercial acceptance. Soil-Teq (which is now owned by AgChem) developed a fertilizer and pesticide applicator that changes rates on the go according to predetermined maps. A team of Texas A&M University engineers, including this author, developed a system that automatically generated maps of the crop yield during harvest. Contemporary precision agriculture uses the global positioning system and geographic information systems to manage each small area within a field.

An example of the future is what we envision for the almost 100 million citrus trees in Florida.

Databases will include historical records of production, soil parameters, tree characteristics, and pests for each tree. The water, fertilizer, and pesticide to each tree will be controlled to maximize economic returns. This procedure would also serve to prevent the overconsumption of water and the excess introduction of chemicals into the environment. Many of the component technologies are currently being tested or are seeing limited commercial adoption.

Accurate sensing in the heterogeneous physical/chemical/biological environments of agriculture is difficult. Accurate control of actuators is also not trivial. For example, imagine mixing and accurately applying granular and liquid materials to many small areas with a 20- meter-wide applicator traveling 30 kilometers per hour.

All other areas of the agricultural industry also require substantial engineering efforts. For example, the possibility of replacing large tractors, which can compact the soil, with small, lightweight robots can’t be effectively evaluated until such robots are designed. As another example, harvesting and processing equipment is needed for the new pharmaceutical crops developed through biotechnology.


Taking A Biological Tilt

Unfortunately, there has been little applied research and development in such areas. The National Science Foundation and other engineering supporters leave the area to the U.S. Department of Agriculture and the land-grant universities. But they are taking a biological tilt, especially to biotechnology. Due to the maturation of the market and the low agricultural crop prices affecting farmers’ purchasing power, the agricultural equipment industry has retrenched and consolidated.

Although there were 186 tractor manufacturers in 1921, there are now only two U.S. corporations, Deere and AGCO, producing a substantial number of tractors. In addition, Fiat-controlled CNH, which includes the remnants of International Harvester and Ford, has a substantial presence.

Perhaps their engineers, and those from companies that make the other types of agricultural equipment, will continue the tradition of improving agricultural mechanization to increase productivity, efficiency, product quality, and environmental protection. Ample amounts of good food will continue to be mankind’s primary need as the world’s population and its desired standard of living continue to increase.