History of American Agriculture

American Agriculture 1776-1990

The history of American agriculture (1776-1990) covers the period from the first English settlers to the modern day. Below are detailed timelines covering farm machinery and technology, transportation, life on the farm, farmers and the land, and crops and livestock.

01
of 05

Farm Machinery and Technology

​​18th century - Oxen and horses for power, crude wooden plows, all sowing by hand, cultivating by hoe, hay and grain cutting with sickle, and threshing with flail

1790s - Cradle and scythe introduced

1793 - Invention of cotton gin
1794 - Thomas Jefferson's moldboard of least resistance tested
1797 - Charles Newbold patented first cast-iron plow

1819 - Jethro Wood patented iron plow with interchangeable parts
1819-25 - U.S. food canning industry established

1830 - About 250-300 labor-hours required to produce 100 bushels (5 acres) of wheat with walking plow, brush harrow, hand broadcast of seed, sickle, and flail
1834 - McCormick reaper patented
1834 - John Lane began to manufacture plows faced with steel saw blades 
1837 - John Deere and Leonard Andrus began manufacturing steel plows
1837 - Practical threshing machine patented

1840s - The growing use of factory-made agricultural machinery increased farmers' need for cash and encouraged commercial farming
1841 - Practical grain drill patented
1842 - First grain elevator, Buffalo, NY
1844 - Practical mowing machine patented
1847 - Irrigation begun in Utah
1849 - Mixed chemical fertilizers sold commercially

1850 - About 75-90 labor-hours required to produce 100 bushels of corn (2-1/2 acres) with walking plow, harrow, and hand planting
1850-70 - Expanded market demand for agricultural products brought adoption of improved technology and resulting increases in farm production
1854 - Self-governing windmill perfected
1856 - 2-horse straddle-row cultivator patented

1862-75 - Change from hand power to horses characterized the first American agricultural revolution
1865-75 - Gang plows and sulky plows came into use
1868 - Steam tractors were tried out
1869 - Spring-tooth harrow or seedbed preparation appeared

1870s - Silos came into use
1870's - Deep-well drilling first widely used
1874 - Glidden barbed wire patented
1874 - Availability of barbed wire allowed fencing of rangeland, ending era of unrestricted, open-range grazing

1880 - William Deering put 3,000 twine binders on the market
1884-90 - Horse-drawn combine used in Pacific coast wheat areas

1890-95 - Cream separators came into wide use
1890-99 - Average annual consumption of commercial fertilizer: 1,845,900 tons 
1890s - Agriculture became increasingly mechanized and commercialized
1890 - 35-40 labor-hours required to produce 100 bushels (2-1/2 acres) of corn with 2-bottom gang plow, disk and peg-tooth harrow, and 2-row planter
1890 - 40-50 labor-hours required to produce 100 bushels (5 acres) of wheat with gang plow, seeder, harrow, binder, thresher, wagons, and horses
1890 - Most basic potentialities of agricultural machinery that was dependent on horsepower had been discovered

1900-1909 - Average annual consumption of commercial fertilizer: 3,738,300
1900-1910 - George Washington Carver, director of agricultural research at Tuskegee Institute, pioneered in finding new uses for peanuts, sweet potatoes, and soybeans, thus helping to diversify southern agriculture.

1910-15 - Big open-geared gas tractors came into use in areas of extensive farming
1910-19 - Average annual consumption of commercial fertilizer: 6,116,700 tons
1915-20 - Enclosed gears developed for tractor
1918 - Small prairie-type combine with auxiliary engine introduced

1920-29 - Average annual consumption of commercial fertilizer: 6,845,800 tons
1920-40 - Gradual increase in farm production resulted from expanded use of mechanized power
1926 - Cotton-stripper developed for High Plains
1926 - Successful light tractor developed

1930-39 - Average annual consumption of commercial fertilizer: 6,599,913 tons
1930s - All-purpose, rubber-tired tractor with complementary machinery came into wide use
1930 - One farmer supplied 9.8 persons in the United States and abroad
1930 - 15-20 labor-hours required to produce 100 bushels (2-1/2 acres) of corn with 2-bottom gang plow, 7-foot tandem disk, 4-section harrow, and 2-row planters, cultivators, and pickers
1930 - 15-20 labor-hours required to produce 100 bushels (5 acres) of wheat with 3-bottom gang plow, tractor, 10-foot tandem disk, harrow, 12-foot combine, and trucks

1940-49 - Average annual consumption of commercial fertilizer: 13,590,466 tons
1940 - One farmer supplied 10.7 persons in the United States and abroad
1941-45 -Frozen foods popularized
1942 - Spindle cottonpicker produced commercially
1945-70 - Change from horses to tractors and the adoption of a group of technological practices characterized the second American agriculture agricultural revolution
1945 - 10-14 labor-hours required to produce 100 bushels (2 acres) of corn with tractor, 3-bottom plow, 10-foot tandem disk, 4-section harrow, 4-row planters and cultivators, and 2-row picker 
1945 - 42 labor-hours required to produce 100 pounds (2/5 acre) of lint cotton with 2 mules, 1-row plow, 1-row cultivator, hand how, and hand pick

1950-59 - Average annual consumption of commercial fertilizer: 22,340,666 tons
1950 - One farmer supplied 15.5 persons in the United States and abroad
1954 - Number of tractors on farms exceeded the number of horses and mules for first times
1955 - 6-12 labor-hours required to produce 100 bushels (4 acres) of wheat with tractor, 10-foot plow, 12-foot role weeder, harrow, 14-foot drill and self-propelled combine, and trucks
Late 1950s - 1960s - Anhydrous ammonia increasingly used as cheap source of nitrogen, spurring higher yields

1960-69 - Average annual consumption of commercial fertilizer: 32,373,713 tons
1960 - One farmer supplied 25.8 persons in the United States and abroad
1965 - 5 labor-hours required to produce 100 pounds (1/5 acre) of lint cotton with tractor, 2-row stalk cutter, 14-foot disk, 4-row bedder, planter, and cultivator, and 2-row harvester
1965 - 5 labor-hours required to produce 100 bushels (3 1/3 acres) of wheat with tractor, 12-foot plow, 14-foot drill, 14-foot self-propelled combine, and trucks
1965 - 99% of sugar beets harvested mechanically
1965 - Federal loans and grants for water/sewer systems began
1968 - 96% of cotton harvested mechanically

1970s - No-tillage agriculture popularized
1970 - One farmer supplied 75.8 persons in the United States and abroad
1975 - 2-3 labor-hours required to produce 100 pounds (1/5 acre) of lint cotton with tractor, 2-row stalk cutter, 20-foot disk, 4 -row bedder and planter, 4-row cultivator with herbicide applicator, and 2-row harvester
1975 - 3-3/4 labor-hours required to produce 100 bushels (3 acres) of wheat with tractor, 30-foot sweep disk, 27-foot drill, 22-foot self-propelled combine, and trucks
1975 - 3-1/3 labor-hours required to produce 100 bushels (1-1/8 acres) of corn with tractor, 5-bottom plow, 20-foot tandem disk, planter, 20-foot herbicide applicator, 12-foot self-propelled combine, and trucks

1980s - More farmers used no-till or low-till methods to curb erosion
1987 - 1-1/2 to 2 labor-hours required to produce 100 pounds (1/5 acre) of lint cotton with tractor, 4-row stalk cutter, 20-foot disk, 6-row bedder and planter, 6-row cultivator with herbicide applicator, and 4-row harvester
1987 - 3 labor-hours required to produce 100 bushels (3 acres) of wheat with tractor, 35-foot sweep disk, 30-foot drill, 25-foot self-propelled combine, and trucks
1987 - 2-3/4 labor-hours required to produce 100 bushels (1-1/8 acres) of corn with tractor, 5-bottom plow, 25-foot tandem disk, planter, 25-foot herbicide applicator, 15-foot self-propelled combine, and trucks 
1989 - After several slow years, the sale of farm equipment rebounded
1989 - More farmers began to use low-input sustainable agriculture (LISA) techniques to decrease chemical applications


 

02
of 05

Transportation

18th century 
Transportation by water, on trails, or through wilderness

1794 
Lancaster Turnpike opened, first successful toll road

1800-30 
The era of turnpike building (toll roads) improved communication and commerce between settlements 
1807 
Robert Fulton demonstrated practicability of steamboats 

1815-20 
Steamboats became important in western trade

1825 
Erie Canal finished 
1825-40 
Era of canal building

1830 
Peter Cooper's railroad steam engine, the Tom Thumb, ran 13 miles 

1830's 
Beginning of railroad era

1840 
3,000 miles of railroad track had been constructed 
1845-57 
Plank road movement

1850's 
Major railroad trunk lines from eastern cities crossed the Appalachian Mountains 
1850's 
Steam and clipper ships improved overseas transportation

1860 
30,000 miles of railroad track had been laid 
1869 
Illinois passed first designated "Granger" law regulating railroads 
1869 
Union Pacific, first transcontinental railroad, completed

1870's 
Refrigerator railroad cars introduced, increasing national markets for fruits and vegetables 

1880 
160,506 miles of railroad in operation 
1887 
Interstate Commerce Act

1893-1905 
Period of railroad consolidation

1909 
The Wrights demonstrated the airplane

1910-25 
Period of road building accompanied increased use of automobiles 
1916 
Railroad network peaks at 254,000 miles  
1916 
Rural Post Roads Act began regular Federal subsidies to road building 
1917-20 
Federal Government operates railroads during war emergency

1920's 
Truckers began to capture trade in perishables and dairy products 
1921 
Federal Government gave more aid for farm-to-market roads 
1925 
Hoch-Smith Resolution required the Interstate Commerce Commission (ICC) to consider agricultural conditions in making railroad rates

1930's 
Farm-to-market roads emphasized in Federal roadbuilding 
1935 
Motor Carrier Act brought trucking under ICC regulation

1942 
Office of Defence Transportation established to coordinate wartime transport needs

1950's 
Trucks and barges competed successfully for agricultural products as railroad rates rose 
1956 
Interstate Highway Act

1960's 
Financial condition of northeastern railroads deteriorated; rail abandonments accelerated 
1960's 
Agricultural shipments by all-cargo planes increased, especially shipments of strawberries and cut flowers

1972-74 
Russian grain sale caused massive tieups in rail system

1980 
Railroad and trucking industries were deregulated

03
of 05

Life on the Farm

17th century 
Farmers endured rough pioneer life while adapting to new environment 
18th century 
Ideas of progress, human perfectibility , rationality, and scientific improvement flourished in the New World 
18th century 
Small family farms predominated, except for plantations in southern coastal areas; housing ranged from crude log cabins to substantial frame, brick, or stone houses; farm families manufactured many necessities

1810-30 
Transfer of manufactures from the farm and home to the shop and factory was greatly accelerated

1840-60 
Growth in manufacturing brought many laborsaving devices to the farm home 
1840-60 
Rural housing improved with use of balloon-frame construction 
1844 
Success of the telegraph revolutionized communications 
1845 
Mail volume increased as postage rated lowered

1860's 
Kerosene lamps became popular 
1865-90 
Sod houses common on the prairies

 

1895 
George B. Seldon was granted U.S. Patent for automobile 
1896 
Rural Free Delivery (RFD) started

1900-20 

Urban influences on rural life intensified 
1908 
Model T Ford paved way for mass production of automobiles 
1908 
President Roosevelt's Country Life Commission was established and focused attention on the problems of farm wives and the difficulty of keeping children on the farm 
1908-17 
Period of the country-life movement

1920s 
Movie houses were becoming common in rural areas 
1921 
Radio broadcasts began 

1930 
58% of all farms had cars 
34% had telephones 
13% had electricity 
1936 
Rural Electrification Act (REA) greatly improved quality of rural life

1940 
58% of all farms had cars 
25% had telephones 
33% had electricity

1950s 
Television widely accepted 
1950s 
Many rural areas lost population as many farm family members sought outside work 
1954 
70.9% of all farms had cars 
49% had telephones
93% had electricity ​

1954 
Social Security coverage extended to farm operators

1962 
REA authorized to finance educational TV in rural areas 

1968 
83% of all farms had phones 
98.4% had electricity

1970s 
Rural areas experienced prosperity and inmigration 

1975 
90% of all farms had phones 
98.6% had electricity

Mid-1980s 

Hard times and indebtedness affected many farmers in the Midwest
04
of 05

Farmers and the Land

17th century 
Small land grants commonly made to individual settlers; large tracts often granted to well-connected colonists  

1619 
First African slaves brought to Virginia; by 1700, slaves were displacing southern indentured servants 
18th century 
English farmers settled in New England villages; Dutch, German, Swedish, Scotch-Irish, and English farmers settled on isolated Middle Colony farmsteads; English and some French farmers settled on plantations in tidewater and on isolated Southern Colony farmsteads in Piedmont; Spanish immigrants, mostly lower middle-class and indentured servants, settled the Southwest and California.

1776 
Continental Congress offered land grants for service in the Continental Army 
1785, 1787 
Ordinances of 1785 and 1787 provided for survey, sale, and government of northwestern lands  
1790 
Total population: 3,929,214 
Farmers made up about 90% of labor force  
1790 
The U.S. area settled extended westward an average of 255 miles; parts of the frontier crossed the Appalachians 
1790-1830 
Sparse immigration into the United States, mostly from the British Isles 
1796 
Public Land Act of 1796 authorized Federal land sales to the public in minimum 640-acre plots at $2 per acre of credit

1800 
Total population: 5,308,483 
1803 
Louisiana Purchase 
1810 
Total population: 7,239,881 
1819 
Florida and other land acquired through treaty with Spain 
1820 
Total population: 9,638,453 
1820 
Land Law of 1820 allowed purchasers to buy as little as 80 acres of public land for a minimum price of $1.25 an acre; credit system abolished

1830 
Total population: 12,866,020 
1830 
The Mississippi River formed the approximate frontier boundary 
1830-37 
Land speculation boom 
1839 
Anti-rent war in New York, a protest against the continued collection of quitrents

1840 
Total population: 17,069,453 
Farm population: 9,012,000 (estimated) 
Farmers made up 69% of labor force 
1841 
Preemption Act gave squatters first rights to buy land 
1845-55 
The potato famine in Ireland and the German Revolution of 1848 greatly increased immigration 
1845-53 
Texas, Oregon, the Mexican cession, and the Gadsden Purchase were added to the Union 
1849 
Gold Rush

1850 
Total population: 23,191,786 
Farm population: 11,680,000 (estimated)  
Farmers made up 64% of labor force 
Number of farms: 1,449,000 
Average acres: 203 
1850s 
Successful farming on the prairies began 
1850 
With the California gold rush, the frontier bypassed the Great Plains and the Rockies and moved to the Pacific coast 
1850-62 
Free land was a vital rural issue 
1854 
Graduation Act reduced price of unsold public lands 
1859-75 
The miners' frontier moved eastward from California toward the westward-moving farmers' and ranchers frontier

1860 
Total population: 31,443,321 
Farm population: 15,141,000 (estimated)  
Farmers made up 58% of labor force 
Number of farms: 2,044,000 
Average acres: 199 
1862 
Homestead Act granted 160 acres to settlers who had worked the land 5 years 
1865-70 
The sharecropping system in the South replaced the old slave plantation system 
1865-90 
Influx of Scandinavian immigrants 
1866-77 
Cattle boom accelerated settlement of Great Plains; range wars developed between farmers and ranchers

1870 
Total population: 38,558,371 
Farm population: 18,373,000 (estimated)  
Farmers made up 53% of labor force 
Number of farms: 2,660,000 
Average acres: 153

1880 
Total population: 50,155,783 
Farm population: 22,981,000 (estimated)  
Farmers made up 49% of labor force 
Number of farms: 4,009,000 
Average acres: 134 
1880s 
Heavy agricultural settlement on the Great Plains began 
1880 
Most humid land already settled 
1880-1914 
Most immigrants were from southeastern Europe 
1887-97 
Drought reduced settlement on the Great Plains

1890 
Total population: 62,941,714 
Farm population: 29,414,000 (estimated)  
Farmers made up 43% of labor force 
Number of farms: 4,565,000 
Average acres: 136 
1890s 
Increases in land under cultivation and number of immigrants becoming farmers caused great rise in agricultural output 
1890 
Census showed that the frontier settlement era was over

1900 
Total population: 75,994,266 
Farm population: 29,414,000 (estimated)  
Farmers made up 38% of labor force 
Number of farms: 5,740,000 
Average acres: 147 
1900-20 
Continued agricultural settlement on the Great Plains 
1902 
Reclamation Act 
1905-07 
Policy of reserving timberlands inaugurated on a large scale

1910 
Total population: 91,972,266 
Farm population: 32,077,00 (estimated)  
Farmers made up 31% of labor force 
Number of farms: 6,366,000 
Average acres: 138 
1909-20 
Dryland farming boom on the Great Plains 
1911-17 
Immigration of agricultural workers from Mexico 
1916 
Stock Raising Homestead Act

1920 
Total population: 105,710,620 
Farm population: 31,614,269 (estimated) 
Farmers made up 27% of labor force 
Number of farms: 6,454,000 
Average acres: 148 
1924 
Immigration Act greatly reduced number of new immigrants

1930 
Total population: 122,775,046 
Farm population: 30,455,350 (estimated) 
Farmers made up 21% of labor force 
Number of farms: 6,295,000 
Average acres: 157 
Irrigated acres: 14,633,252 
1932-36 
Drought and dust-bowl conditions developed 
1934 
Executive orders withdrew public lands from settlement, location, sale, or entry 
1934 
Taylor Grazing Act

1940 
Total population: 131,820.000  
Farm population: 30,840,000 (estimated)  
Farmers made up 18% of labor force 
Number of farms: 6,102,000 
Average acres: 175 
Irrigated acres: 17,942,968 
1940s 
Many former southern sharecroppers migrated to war-related jobs in cities

1950 
Total population: 151,132,000  
Farm population: 25,058,000 (estimated)  
Farmers made up 12.2% of labor force 
Number of farms: 5,388,000 
Average acres: 216  
Irrigated acres: 25,634,869 
1956 
Legislation passed providing for Great Plains Conservation Program

1960 
Total population: 180,007,000  
Farm population: 15,635,000 (estimated)  
Farmers made up 8.3% of labor force 
Number of farms: 3,711,000 
Average acres: 303 
Irrigated acres: 33,829,000 
1960s 
State legislation increased to keep land in farming 
1964 
Wilderness Act 
1965 
Farmers made up 6.4% of labor force

1970 
Total population: 204,335,000 
Farm population: 9,712,000 (estimated)  
Farmers made up 4.6% of labor force 
Number of farms: 2,780,000 
Average acres: 390

1980, 1990 
Total population: 227,020,000 and 246,081,000  
Farm population: 6,051,00 and 4,591,000  
Farmers made up 3.4% and 2.6% of labor force 
Number of farms: 2,439,510 and 2,143,150 
Average acres: 426 and 461 
Irrigated acres: 50,350,000 (1978) and 46,386,000 (1987) 
1980s 
For the first time since the 19th century, foreigners (Europeans and Japanese primarily) began to purchase significant acreages of farmland and ranchland 
1986 
The Southeast's worst summer drought on record took a severe toll on many farmers 
1987 
Farmland values bottomed out after a 6-year decline, signalling both a turnaround in the farm economy and increased competition with other countries' exports 
1988 
Scientists warned that the possibility of global warming may affect the future viability of American farming 
1988 
One of the worst droughts in the Nation's history hit midwestern farmers

05
of 05

Crops and Livestock

16th century 
Spanish cattle introduced into the Southwest 
17th and 18th centuries 
All forms of domestic livestock, except turkeys, were imported at some time 
17th and 18th centuries 
Crops borrowed from Indians included maize, sweet potatoes, tomatoes, pumpkins, gourds, squashes, watermelons, beans, grapes, berries, pecans, black walnuts, peanuts, maple sugar, tobacco, and cotton; white potatoes indigenous to South America 
17th and 18th centuries 
New U.S. crops from Europe included clover, alfalfa, timothy, small grains, and fruits and vegetables 
17th and 18th centuries 
African slaves introduced grain and sweet sorghum, melons, okra, and peanuts 
18th centuries 
Tobacco was the chief cash crop of the South

1793 
First Merino sheep imported 
1795-1815 
The sheep industry in New England was greatly emphasized

1805-15 
Cotton began to replace tobacco as the chief southern cash crop 
1810-15 
Demand for Merino sheep sweeps the country 
1815-25 
Competition with western farm areas began to force New England farmers out of wheat and meat production and into dairying, trucking, and, later, tobacco production 
1815-30 
Cotton became the most important cash crop in the Old South 
1819 
Secretary of Treasury instructed consuls to collect seeds, plants, and agricultural inventions 
1820s 
Poland-China and Duroc-Jersey swine were being developed, and Berkshire swine were imported 
1821 
Edmund Ruffin's first Essay on Calcareous Manures

1836-62 
Patent Office collected agricultural information and distributed seeds 
1830s-1850s 
Improved transportation to the West forced eastern staple growers into more varied production for nearby urban centers

1840 
Justos Liebig's Organic Chemistry appeared 
1840-1850 
New York, Pennsylvania, and Ohio were the chief wheat States 
1840-60 
Hereford, Ayrshire, Galloway, Jersey, and Holstein cattle were imported and bred 
1846 
First herdbook for Shorthorn cattle 
1849 
First poultry exhibition in the United States

1850s 
Commercial corn and wheat belts began to develop; wheat occupied the newer and cheaper land west of the corn areas, and was constantly being forced westward by rising land values and the encroachment of the corn areas 
1850s 
Alfalfa grown on the west coast 
1858 
Grimm alfalfa introduced

1860s 
The Cotton Belt began to move westward 
1860s 
The corn Belt began stabilizing in its present area 
1860 
Wisconsin and Illinois were the chief wheat States 
1866-86 
The days of the cattlemen on the Great Plains

1870s 
Increased specialization in farm production 
1870 
Illinois, Iowa, and Ohio were the chief wheat States 
1870 
Foot-and-mouth disease first reported in the United States 
1874-76 
Grasshopper plagues serious in the West 
1877 
U.S. Entomological Commission established for work on grasshopper control

1880's 
The cattle industry moved into the western and southwestern Great Plains
1882 
Bordeau mixture (fungicide) discovered in France and soon used in the United States 
1882 
Robert Koch discovered tubercle bacillus 
Mid-1880s 
Texas was becoming the chief cotton State 
1886-87 
Blizzards, following drought and overgrazing, disastrous to northern Great Plains cattle industry 
1889 
Bureau of Animal Industry discovered carrier of tick fever

1890 
Minnesota, California, and Illinois were the chief wheat States 
1890 
Babcock butterfat test devised 
1892 
Boll weevil crossed the Rio Grande and began to spread north and east 
1892 
Eradication of pleuropneumonia 
1899 
Improved method of anthrax inoculation

1900-10 
Turkey red wheat was becoming important as commercial crop 
1900-20 
Extensive experimental work was carried out to breed disease-resistant varieties of plants, to improve plant yield and quality, and to increase the productivity of farm animal strains 
1903 
Hog cholera serum developed 
1904 
First serious stem-rust epidemic affecting wheat

1910 
North Dakota, Kansas, and Minnesota were the chief wheat States 
1910 
Durum wheats were becoming important commercial crops 
1910 
35 States and territories required tuberculin testing of all entering cattle 
1910-20 
Grain production reached into the most arid sections of the Great Plains 
1912 
Marquis wheat introduced 
1912 
Panama and Colombia sheep developed 
1917 
Kansas red wheat distributed

1926 
Ceres wheat distributed 
1926 
First hybrid-seed corn company organized 
1926 
Targhee sheep developed

1930-35 
Use of hybrid-seed corn became common in the Corn Belt 
1934 
Thatcher wheat distributed 
1934 
Landrace hogs imported from Denmark 
1938 
Cooperative organized for artificial insemination of dairy cattle

1940s and 1950s 
Acreages of crops, such as oats, required for horse and mule feed dropped sharply as farms used more tractors 
1945-55 
Increased use of herbicides and pesticides 
1947 
United States began formal cooperation with Mexico to prevent spread of foot-and-mouth disease

1960s 
Soybean acreage expanded as farmers used soybeans as an alternative to other crops 
1960 
96% of corn acreage planted with hybrid seed 
1961 
Gaines wheat distributed 
1966 
Fortuna wheat distributed

1970 
Plant Variety Protection Act 
1970 
Nobel Peace Prize awarded to Norman Borlaug for developing high-yielding wheat varieties 
1975 
Lancota wheat introduced 
1978 
Hog cholera officially declared eradicate 
1979 
Purcell winter wheat introduced

1980s 
Biotechnology became a viable technique for improving crop and livestock products  
1883-84 
Avian influenza of poultry eradicated before it spread beyond a few Pennsylvania counties 
1986 
Antismoking campaigns and legislation began to affect the tobacco industry

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Bellis, Mary. "History of American Agriculture." ThoughtCo, Aug. 16, 2016, thoughtco.com/history-of-american-agriculture-farm-machinery-4074385. Bellis, Mary. (2016, August 16). History of American Agriculture. Retrieved from https://www.thoughtco.com/history-of-american-agriculture-farm-machinery-4074385 Bellis, Mary. "History of American Agriculture." ThoughtCo. https://www.thoughtco.com/history-of-american-agriculture-farm-machinery-4074385 (accessed December 16, 2017).