tillage

1. Cultivation of land.
2. Land that has been tilled.

Farmers perform tillage when they prepare soil for the raising of crops. Soil tillage has three primary purposes. Prior to planting, farmers use tillage to mix compost, manure, and other fertilizers into the root zone where growing plant roots may reach it. Tillage also aids seed germination by creating a smooth, uniform soil surface for planting. After planting, farmers use tillage to control weeds between crop plants—including vegetable, fruit, forest, medicinal, and farm crops. Since early agriculture, tillage has been the first step in the process that makes it possible to harvest food from plants. However, soil tillage has come under close scrutiny since soil is recognized as a natural resource that deserves protection. Agronomists (scientists who study crop production and soil management) are concerned because erosion (soil loss) from tillage is one of the most significant problems in agriculture. If left unchecked, soil erosion leads to loss of soil productivity, as well as off-site deposition of sediments and farm chemicals that pollute surface and groundwater.

Early History of Tillage

Soil tillage had its beginnings ten to twelve millennia ago in the Near East, as early farmers used a digging stick to loosen the soil before planting seeds. The tool evolved from digging stick to spade to triangular blade, and was made of wood, stone, and ultimately metal. One or more people likely used their bodies to pull the first wooden plows. Animals began pulling plows around 3000 B.C.E. in Mesopotamia. Jethro Tull (1674–1741), a pioneering British soil physicist, was the first to recognize that loosening soil helps to supply plant roots with nutrients.

In North America, agricultural innovators copied European trends. Charles Newbold patented the first cast-iron plow in the late 1700s. In 1837, John Deere and Leonard Andrus began manufacturing steel plows. By the 1840s, the growing use of manufactured equipment had increased the farmers' need for cash, thus encouraging the rise of commercial farming. Agriculture, society, and economics were closely linked, as George Marsh said in an address delivered in 1847 to the Agricultural Society of Rutland County, Vermont: "Pure pastoral life, as I have said, advances man to but an humble stage of civilization, but when it is merged in agriculture, and the regular tillage of the soil commences, he is brought under the dominion of new influences, and the whole economy of domestic and social life is completely revolutionized." Marsh explained that once cultivation of soil begins, all aspects of society are affected by changes: "Hence arises the necessity of fixed habitations and store houses, and of laws which shall recognize and protect private exclusive right to determinate portions of the common earth, and sanction and regulate the right of inheritance, and the power of alienation and devise, in short the whole frame work of civil society."

Horses and mules had taken over the work of draft oxen by the late 1800s. As agriculture became increasingly mechanized and commercialized, tractors became more common and replaced most draft animals by the early to mid-1900s. Until then, the size of most family farms was restricted to the land that a man could work using several horses. With the advent of the light, gasoline-powered tractor, both family and commercial farms added crop area and prospered.

The Dust Bowl

Tractors helped to create farm fields that stretched far westward, setting the stage for the Dust Bowl in the 1930s. Open grassland in the southwestern Great Plains region of the United States was settled and farmed by homesteaders who planted row crops and grazed their cattle. Before farmers came, the region was covered by hardy grasses that held the soil in place despite long droughts and torrential rains. Tillage combined with drought left the soil exposed to wind erosion. Lightweight soil components—organic matter, clay, and silt—were carried great distances by the winds, while sand and heavier materials drifted against houses, fences, and barns. This drifting debris buried farm buildings and darkened the sky as far as the Atlantic coast. Over a period of ten years, millions of acres of farmland became useless, and hundreds of thousands of people were forced to leave their homes.

The Dust Bowl gave impetus to the soil conservation movement; nevertheless, mechanization continued to spread. In 1938, Hugh Bennett and Walter Lowder-milk of the United States Soil Conservation Service wrote in the Yearbook of Agriculture: "Soil erosion is as old as farming. It began when the first heavy rain struck the first furrow turned by a crude implement of tillage in the hands of prehistoric man. It has been going on ever since, wherever man's culture of the earth has bared the soil to rain and wind."

Conservation Tillage and Sustainable Agriculture

By 1954, the number of tractors on farms exceeded the number of horses and mules for the first time. The increasing availability of agricultural chemicals in the midto late-1900s, including weed killers that did not harm crop plants, further changed crop and soil management practices. "Conservation tillage"—a broad spectrum of farming methods that help to reduce soil erosion due to wind and water and help to reduce labor and fuel—gained a following among farmers in the 1980s. Early methods of conservation tillage, such as no-tillage, were un sustainable since they relied heavily on chemical weed killers called herbicides. The no-tillage method worked well to control both soil erosion and weeds, while requiring less energy. However, herbicides were highly toxic to people and wildlife and their manufacture and use caused environmental pollution. Tillage reduction methods were fine-tuned to suit local conditions throughout the United States.

By 1989, a far-sighted handful of new-generation farmers became interested in lowering costs, avoiding agricultural chemicals, and saving soil. They started the agricultural movement that became known as "sustainable agriculture." Low-input methods meet the needs of more farmers each year. They are promoted by a program of the United States Department of Agriculture called Sustainable Agriculture Research and Education (SARE). Farmers practicing sustainable agriculture produce food and fiber while enhancing environmental quality and natural resources, make the most efficient use of nonrenewable resources and on-farm resources. Further, they integrate natural biological cycles and pest controls and sustain the economic viability of farm operations.

Today's tillage practices reflect society's concern with environmental quality, and the farmer's need to reduce costs while preventing soil erosion and compaction. However, significant amounts of soil are still lost annually around the world where soil is not protected.

Bibliography

Blann, K., review of Coughenour, C. M., and S. Chamala, "Conservation Tillage and Cropping Innovation: Constructing the New Culture of Agriculture," in Conservation Ecology 5 (2): 2 (2001). Ames: Iowa State University Press.

Hillel, Daniel. Environmental Soil Physics. San Diego: Academic Press, 1998.

Jasa, P. J., D. P. Shelton, A. J. Jones, and E. C. Dickey. Conservation Tillage and Planting Systems. Bulletin G91-1046. Lincoln, Neb.: Cooperative Extension, Institute of Agriculture and Natural Resources, University of Nebraska, Lincoln, 1997.

Library of Congress. The Evolution of the Conservation Movement 1850–1920. Library of Congress: Washington, D.C.

Robinson, Clay. Dr. Dirt. Online notes for courses in soil science. Canyon, Tex.: West Texas A&M University.

United States Department of Agriculture, Economic Research Service. A History of American Agriculture 1776–1990. Washington, D.C.: U.S. Government Printing Office, n.d.

—Patricia S. Michalak

The noun has 2 meanings:

Meaning #1: arable land that is worked by plowing and sowing and raising crops
  Synonyms: cultivated land, farmland, plowland, ploughland, tilled land, tilth

Meaning #2: the cultivation of soil for raising crops

Cultivating after early rain.

Tillage is the agricultural preparation of the soil by ploughing, ripping, or turning it. Tillage can also mean the land that is tilled. There are two types of tillage: primary and secondary tillage.

Contents 1 Tillage systems 1.1 Intensive tillage 1.2 Reduced tillage 1.3 Conservation tillage 1.4 Purposes Of Tillage 1.5 General comments 2 Definitions 3 History of tilling 4 Alternatives to tilling 5 See also 6 References 6.1 Further information

Tillage systems

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Intensive tillage

Intensive tillage systems leave less than 15% crop residue cover less than 500 pounds per acre (560 kg/ha) of small grain residue. These types of tillage systems are often referred to as conventional tillage systems but as reduced and conservation tillage systems have been more widely adopted, it is often not appropriate to refer to this type of system as conventional. These systems involve often multiple operations with implements such as a mold board, disk, and/or chisel plow. Then a finisher with a harrow, rolling basket, and cutter can be used to prepare the seed bed. There are many variations.

Reduced tillage

Reduced tillage systems leave between 15 and 30% residue cover on the soil or 500 to 1000 pounds per acre (560 to 1100 kg/ha) of small grain residue during the critical erosion period. This may involve the use of a chisel plow, field cultivators, or other implements. See the general comments below to see how they can affect the amount of residue.

Conservation tillage

Conservation tillage systems are methods of soil tillage which leave a minimum of 30% of crop residue on the soil surface or at least 1,000 lb/ac (1,100 kg/ha) of small grain residue on the surface during the critical soil erosion period. This slows water movement, which reduces the amount of soil erosion. Conservation tillage systems also benefit farmers by reducing fuel consumption and soil compaction. By reducing the number of times the farmer travels over the field, farmers realize significant savings in fuel and labor. Conservation tillage was used on about 38%, 109,000,000 acres (440,000 km²), of all US cropland, 293,000,000 acres (1,190,000 km²) planted as of 2004 according to the USDA.

However, conservation tillage systems delay warming of the soil due to the reduction of dark earth exposure to the warmth of the spring sun, thus delaying the planting of the next year's spring crop. ^[1]

• No-till
• Strip-Till
• Mulch-Till
• Ridge-Till

Purposes Of Tillage

• Ploughing loosens and aerates the soil which in turn facilitates deeper penetration of roots. A drawback is the compaction of the lower layers of soil.^{[citation needed]}
• It helps in the growth of microorganisms present in the soil and thus, maintains the fertility of the soil, though fertility can decline as microorganisms' boom period after tilling is followed by a bust period. It is debatable whether worms benefit or suffer from tillage.^{[citation needed]}
• It helps in the mixing of organic matter(humus)and nutrients evenly throughout the soil.
• It is used for destroying weeds.

General comments

• The type of implement makes the most difference, although other factors can have an effect^[2].
• Tilling in absolute darkness (night tillage) might reduce the number of weeds that sprout following the tilling operation by half. Light is necessary to break the dormancy of some weed species' seed, so if fewer seeds are exposed to light during the tilling process, fewer will sprout. This may help reduce the amount of herbicides needed for weed control^[3].
• Greater speeds, when using certain tillage implements (disks and chisel plows), lead to more intensive tillage (ie., less residue is on the soil surface).
• Increasing the angle of disks causes residues to be buried more deeply. Increasing their concavity makes them more aggressive.
• Chisel plows can have spikes or sweeps. Spikes are more aggressive.
• Percentage residue is used to compare tillage systems because the amount of crop residue affects the soil loss due to erosion ^[2][4].
• See Soybean management practices to see what types of tillage are currently recommended for Soybean Production.

Definitions

Primary tillage loosens the soil and mixes in fertilizer and/or plant material, resulting in soil with a rough texture.

Secondary tillage produces finer soil and sometimes shapes the rows. It can be done by an using various combinations of equipment: plough, disk plough, harrow, dibble, hoe, shovel, rotary tillers, subsoiler, ridge or bed forming tillers, roller.

Weed plants (seeds, tubers, etc.) may be exhausted by repeated tilling. The weeds expend energy to reach the surface, and then get turned into the soil by tilling. The cycle is repeated until the weeds are dead.

History of tilling

Tilling was first performed via human labor, sometimes involving slaves. Hoofed animals could also be used to till soil via trampling. The wooden plough was then invented. It could be pulled by mule, ox, elephant, water buffalo, or similar sturdy animal. Horses are generally unsuitable, though breeds such as the Clydesdale could work. The steel plough allowed farming in the American Midwest, where tough prairie grasses and rocks caused trouble. Soon after 1900, the farm tractor was introduced, which eventually made modern large-scale agriculture possible.

Alternatives to tilling

Modern agricultural science has greatly reduced the use of tillage. Crops can be grown for several years without any tillage through the use of herbicides to control weeds, crop varieties that tolerate packed soil, and equipment that can plant seeds or fumigate the soil without really digging it up. This practice, called no-till farming, reduces costs and environmental change by reducing soil erosion and diesel fuel usage (although it does require the use of herbicides). Most organic farming tends to require extensive tilling, as did most farming throughout history, although researchers are investigating farming in polyculture that would eliminate the need for both tillage and pesticides, such as no-dig gardening.

See also

• Advance sowing
• Optimum water content for tillage
• SWEEP (Soil and Water Environmental Enhancement program)
• TERON (Tillage erosion)

References

Sprague, Milton A., and Glover B. Triplett. 1986. No-tillage and surface-tillage agriculture : the tillage revolution. New York, Wiley. ISBN 978-0-471-88410-1

Troeh, Frederick R., J. Arthur Hobbs, Roy L. Donahue. 1991. Soil and water conservation for productivity and environmental protection, 2nd ed. Englewood Cliffs, N.J., Prentice-Hall. ISBN 978-0130968074

Soil Science of America. 2009. Glossary of Soil Science Terms. [Online]. Available at https://www.soils.org/publications/soils-glossary (28 Sep 2009; verified 28 Sep 2009). Soil Science of America, Madison, WI.

1. ^ Strip Till for Field Crop Production
2. ^ ^{a b} Conservation Tillage and Residue Management to Reduce Soil Erosion University of Missouri: Extension
3. ^ http://www.ars.usda.gov/is/AR/archive/dec95/tilling1295.htm
4. ^ Methods for measuring crop residue Integrated Crop Management, May 2002

Further information

• Brady, Nyle C.; R.R. Weil (2002). The nature and property of soils, 13th edition. New Jersey: Prentice Hall. ISBN 0-13-016763-0. 
• Natural Resource Conservation Service
• Farm Bill Conservation Provisions
• Conservation Tillage Conservation Technology Information Centre
• Yusuf, Raji I.; Siemens, John C.; Bullock, Donald G. (November 1999). "Growth Analysis of Soybean under No-Tillage and Conventional Tillage Systems". Agronomy Journal (Madison, WI: American Society of Agronomy) 91: 928-933. ISSN 1435-0645. http://agron.scijournals.org/cgi/content/abstract/91/6/928. Retrieved October 2009. 

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