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crop rotation

crop rotation An agricultural practice in which different crops are cultivated in succession on the same area of land over a period of time so as to maintain soil fertility and reduce the adverse effects of pests. Legumes are important in the rotation as they are a source of nitrogen for the soil (see nitrogen fixation; root nodule). In the UK, other crops that may be included in a typical four-stage rotation are wheat, barley, and root crops. However, the use of pesticides enables the monoculture of crops in modern farming systems (see agriculture).

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crop rotation

crop rotation Practice of successively growing different crops on the same field. Rotated crops generally complement each other, each providing nutrients required by the others.

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Crop Rotation

Crop Rotation

History

Current crop rotation practices

Resources

Crop rotation is a method of maintaining soil fertility and structure by planting a particular parcel of agricultural land with alternating plant species. Most crop rotation schedules require that a field contain a different crop each year, and some schemes incorporate times when the field remains uncultivated, or lies fallow. Farmers rotate crops to control erosion, promote soil fertility, contain plant diseases, prevent insect infestations, and discourage weeds. Crop rotation has been an important agricultural tool for thousands of years. Modern organic farmers depend on crop rotation to maintain soil fertility and to fight pests and weeds, functions that conventional farmers carry out with chemical fertilizers and pesticides. Crop rotation can also prevent or correct some of the problems associated with monocultures (single crop farms),

including persistent weeds, insect infestations, and decreased resistance to plant diseases.

History

For over 2, 000 years, since the Romans spread their farming practices throughout the Roman Empire, European farmers followed a Roman cropping system calledfood, feed, and fallow.Farmers divided their land into three sections, and each year planted a food grain such as wheat on one section, barley or oats as feed for livestock on another, and let the third plot lie fallow. On this schedule, each section lay fallow and recovered some of its nutrients and organic matter every third year before it was again sown with wheat. Farmers following thefood, feed, and fallowsystem typically only harvested six to ten times as much seed as they had sown, and saved a sixth to a tenth of their harvest to sow the following year. Low yields left little grain for storage; crops failed and people often starved during years of flood, drought, or pest infestation.

The size of agricultural allotments in Europe gradually increased beginning in the fifteenth century, allowing farmers more space to experiment with different crop rotation schedules. By 1800, many European farmers had adopted a four-year rotation cycle developed in Holland and introduced in Great Britain by Viscount Charles (Turnip) Townshend in the mid-1700s. The four-field system rotated wheat, barley, a root crop like turnips, and a nitrogen-fixing crop like clover. Livestock grazed directly on the clover, and consumed the root crop in the field. In the new system, fields were always planted with either food or feed, increasing both grain yields and livestock productivity. Furthermore, adding a nitrogen-fixing crop and allowing manure to accumulate directly on the fields improved soil fertility; eliminating a fallow period insured that the land was protected from soil erosion by stabilizing vegetation throughout the cycle. In the United States, crop rotation was developed in large part because of the research and educational efforts of American botanist George Washington Carver (18641943).

Subsistence farmers in tropical South America and Africa followed a less orderly crop rotation system called slash and burn agriculture. Slash and burn rotation involves cutting and burning nutrient-rich tropical vegetation in place to enhance a plot of nutrient-poor tropical soil, then planting crops on the plot for several years, and moving on to a new plot. Slash and burn agriculture is a successful strategy as long as the agricultural plots remain small in relation to the surrounding rainforest, and the plot has many years to recover before being cultivated again. Large-scale slash and burn agriculture results in permanent destruction of rainforest ecosystems, and in complete loss of agricultural productivity on the deforested land.

Crop rotation fell out of favor in developed nations in the 1950s, when farmers found they could maintain high-yield monoculture crops by applying newly developed chemical fertilizers, pesticides, and weed killers to their fields. Large-scale commercial agriculture that requires prescribed chemical treatments has become the norm in most developed nations, including the United States. However, substantial concerns about the effect of agricultural chemicals on human health, and damage to soil structure and fertility by monoculture crops, have led many farmers to return to more natural practices like crop rotation in recent decades. So-called conventional farmers use crop rotation in concert with chemical treatments. Organic farmers, who cannot by definition use chemical treatments, rely entirely upon methods like crop rotation to maintain soil health and profitable crop yields.

Current crop rotation practices

Because climate, soil type, extent of erosion, and suitable cash crops vary around the globe, rotation schemes vary as well. The principles of crop rotation, however, are universal: to maintain soil health, combat pests and weeds, and slow erosion farmers should alternate crops with different characteristicssod-base crops with row crops, weed-suppressing crops with those that do not suppress weeds, crops susceptible to specific insects with those that are not, and soil-enhancing crops with those that do not enhance soils.

Farmers use cover crops to stabilize soils during the off-season when a cash crop has been harvested. Cover crops are typically grown during dry or cold seasons when erosion and nutrient depletion threaten exposed soil. Slow-starting legume crops like sweet clover, red clover, crimson clover, and vetch can be planted during the cash crops growing season. These nitrogen-fixing legumes also restore nitrogen to depleted soils during the off-season, which will benefit the next cash crop. Farmers typically plant fast-growing crops like rye, oats, ryegrass, and Austrian winter peas after harvesting

KEY TERMS

Fallow Cultivated land that is allowed to lie idle during the growing season so that it can recover some of its nutrients and organic matter.

Nutrients The portion of the soil necessary to plants for growth, including nitrogen, potassium, and other minerals.

Organic matter The carbonaceous portion of the soil that derives from once living matter, including, for the most part, plants.

the cash crop. Cover crops are plowed into the soil as green manure at the end of the season, a practice that increases soil organic content, improves structure, and increases permeability.

Increasing the number of years of grass, or forage, crops in a rotation schedule usually improves soil stability and permeability to air and water. Sloping land may experience excessive soil loss if row crops like corn, or small-grain crops like wheat, are grown on it for too many years in a row. Rotation with sod-based forage crops keeps soil loss within tolerable limits. Furthermore, forage crops can reverse the depletion of organic nutrients and soil compaction that occur under corn and wheat.

Crop rotation also works to control infestations of crop-damaging insects and weeds. Crop alternation interrupts the reproductive cycles of insects preying on a specific plant. For example, a farmer can help control cyst nematodes, parasites that damage soybeans, by planting soybeans every other year. Crop rotation discourages weeds by supporting healthier crop plants that out compete wild species for nutrients and water, and by disrupting the weed-friendly ecosystems that form in long-term monocultures. Rotation schedules that involve small fields, a large variety of rotated crops, and a long repeat interval contain insect infestations and weeds most successfully. Complex rotations keep weeds and insects guessing, and farmers can exert further control by planting certain crops next to each other. For example, a chinch bug infestation in a wheat field can be contained by planting soybeans in the next field instead of a chinch bug host like forage sorghum.

Farmers undertaking crop rotations must plan their planting more carefully than those who plant the same crop year after year. Using a simple principle, that there are the same number of fields or groups of fields as there are years in the rotation, farmers can assure that they produce consistent amounts of each crop each year even though the crops shift to different fields.

Resources

BOOKS

Atlieri, Miguel Angel. Biodiversity and Pest Management in Agroecosystems. New York: Food Products Press, 2004.

Clements, David, and Anil Shrestha, eds. New Dimensions in Agroecology. Binghamton, NY: Food Products Press, 2004.

Hatfield, Jerry L, ed. The Farmers Decision: Balancing Economic Agriculture Production with Environmental Quality. Ankeny, IA: Soil and Water Conservation Society, 2005.

Pollan, Michael. Botany of Desire: A Plants Eye View of the World. New York: Random House, 2001.

Taji, Acram, and John Reganold, eds. Organic Agriculture: A Global Perspective. Collingwood, Canada: CSIRO Publishing, 2006.

OTHER

Organic Farming Research Foundation (OFRF).Home page for OFRF.<http://www.ofrf.org/index.html.> (accessed November 12, 2006).

Beth Hanson

Laurie Duncan

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"Crop Rotation." The Gale Encyclopedia of Science. . Retrieved November 10, 2018 from Encyclopedia.com: https://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/crop-rotation

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  • In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.

Crop Rotation

Crop rotation

Crop rotation is a method of maintaining soil fertility and structure by planting a particular parcel of agricultural land with alternating plant species. Most crop rotation schedules require that a field contain a different crop each year, and some schemes incorporate times when the field remains uncultivated, or lies fallow. Farmers rotate crops to control erosion , promote soil fertility, contain plant diseases , prevent insect infestations, and discourage weeds. Crop rotation has been an important agricultural tool for thousands of years. Modern organic farmers depend on crop rotation to maintain soil fertility and to fight pests and weeds, functions that conventional farmers carry out with chemical fertilizers and pesticides . Crop rotation can also prevent or correct some of the problems associated with monocultures (single crop farms), including persistent weeds, insect infestations, and decreased resistance to plant diseases.


History

For 2,000 years, since the Romans spread their farming practices throughout the Roman Empire, European farmers followed a Roman cropping system called "food, feed, and fallow." Farmers divided their land into three sections, and each year planted a food grain such as wheat on one section, barley or oats as feed for livestock on another, and let the third plot lie fallow. On this schedule, each section lay fallow and recovered some of its nutrients and organic matter every third year before it was again sown with wheat. Farmers following the "food, feed, fallow" system typically only harvested six to ten times as much seed as they had sown, and saved a sixth to a tenth of their harvest to sow the following year. Low yields left little grain for storage; crops failed and people often starved during years of flood, drought , or pest infestation.

The size of agricultural allotments in Europe gradually increased beginning in the fifteenth century, allowing farmers more space to experiment with different crop rotation schedules. By 1800, many European farmers had adopted a four-year rotation cycle developed in Holland and introduced in Great Britain by Viscount Charles "Turnip" Townshend in the mid-1700s. The four-field system rotated wheat, barley, a root crop like turnips, and a nitrogen-fixing crop like clover. Livestock grazed directly on the clover, and consumed the root crop in the field. In the new system, fields were always planted with either food or feed, increasing both grain yields and livestock productivity. Furthermore, adding a nitrogen-fixing crop and allowing manure to accumulate directly on the fields improved soil fertility; eliminating a fallow period insured that the land was protected from soil erosion by stabilizing vegetation throughout the cycle.

Subsistence farmers in tropical South America and Africa followed a less orderly crop rotation system called "slash and burn" agriculture. Slash and burn rotation involves cutting and burning nutrient-rich tropical vegetation in place to enhance a plot of nutrient-poor tropical soil, then planting crops on the plot for several years, and moving on to a new plot. Slash and burn agriculture is a successful strategy as long as the agricultural plots remain small in relation to the surrounding rainforest , and the plot has many years to recover before being cultivated again. Large-scale slash and burn agriculture results in permanent destruction of rainforest ecosystems, and in complete loss of agricultural productivity on the deforested land.

Crop rotation fell out of favor in developed nations in the 1950s, when farmers found they could maintain high-yield monoculture crops by applying newly developed chemical fertilizers, pesticides, and weed killers to their fields. Large-scale commercial agriculture that requires prescribed chemical treatments has become the norm in most developed nations, including the United States. However, substantial concerns about the effect of agricultural chemicals on human health, and damage to soil structure and fertility by monoculture crops, have led many farmers to return to more "natural" practices like crop rotation in recent decades. So-called conventional farmers use crop rotation in concert with chemical treatments. Organic farmers, who cannot by definition use chemical treatments, rely entirely upon methods like crop rotation to maintain soil health and profitable crop yields.

Current crop rotation practices

Because climate, soil type, extent of erosion, and suitable cash crops vary around the globe, rotation schemes vary as well. The principles of crop rotation, however, are universal: to maintain soil health, combat pests and weeds, and slow erosion farmers should alternate crops with different characteristics—sod-base crops with row crops, weed-suppressing crops with those that do not suppress weeds, crops susceptible to specific insects with those that are not, and soil-enhancing crops with those that do not enhance soils.

Farmers use cover crops to stabilize soils during the off-season when a cash crop has been harvested. Cover crops are typically grown during dry or cold seasons when erosion and nutrient depletion threaten exposed soil. Slow-starting legume crops like sweet clover, red clover, crimson clover, and vetch can be planted during the cash crop's growing season. These nitrogen-fixing legumes also restore nitrogen to depleted soils during the off-season, which will benefit the next cash crop. Farmers typically plant fast-growing crops like rye, oats, ryegrass, and Austrian winter peas after harvesting the cash crop. Cover crops are plowed into the soil as "green manure" at the end of the season, a practice that increases soil organic content, improves structure, and increases permeability.

Increasing the number of years of grass, or forage, crops in a rotation schedule usually improves soil stability and permeability to air and water . Sloping land may experience excessive soil loss if row crops like corn, or small-grain crops like wheat, are grown on it for too many years in a row. Rotation with sod-based forage crops keeps soil loss within tolerable limits. Furthemore, forage crops can reverse the depletion of organic nutrients and soil compaction that occur under corn and wheat.

Crop rotation also works to control infestations of crop-damaging insects and weeds. Crop alternation interrupts the reproductive cycles of insects preying on a specific plant. For example, a farmer can help control cyst nematodes, parasites that damage soybeans, by planting soybeans every other year. Crop rotation discourages weeds by supporting healthier crop plants that out compete wild species for nutrients and water, and by disrupting the weed-friendly "ecosystems" that form in long-term monocultures. Rotation schedules that involve small fields, a large variety of rotated crops, and a long repeat interval contain insect infestations and weeds most successfully. Complex rotations keep weeds and insects guessing, and farmers can exert further control by planting certain crops next to each other. For example, a chinch bug infestation in a wheat field can be contained by planting soybeans in the next field instead of a chinch bug host like forage sorghum .

Farmers undertaking crop rotations must plan their planting more carefully than those who plant the same crop year after year. Using a simple principle, that there are the same number of fields or groups of fields as there are years in the rotation, farmers can assure that they produce consistent amounts of each crop each year even though the crops shift to different fields.

Resources

books

Bender, Jim. Future Harvest: Pesticide Free Farming. Lincoln, NB: University of Nebraska, 1994.

Pollan, Michael. Botany of Desire: A Plant's Eye View of theWorld. New York: Random House, 2001.

Troeh, Frederick R., and Louis M. Thompson. Soils and SoilFertility. New York: Oxford University Press, 1993.


organizations

Organic Farming Research Foundation, P.O. Box 440 Santa Cruz, CA, 95061. (831) 426-6606. <http://www.ofrf.org/index.html.>


Beth Hanson
Laurie Duncan

KEY TERMS

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fallow

—Cultivated land that is allowed to lie idle during the growing season so that it can recover some of its nutrients and organic matter.

Nutrients

—The portion of the soil necessary to plants for growth, including nitrogen, potassium, and other minerals.

Organic matter

—The carbonaceous portion of the soil that derives from once living matter, including, for the most part, plants.

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"Crop Rotation." The Gale Encyclopedia of Science. . Encyclopedia.com. 10 Nov. 2018 <https://www.encyclopedia.com>.

"Crop Rotation." The Gale Encyclopedia of Science. . Encyclopedia.com. (November 10, 2018). https://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/crop-rotation-0

"Crop Rotation." The Gale Encyclopedia of Science. . Retrieved November 10, 2018 from Encyclopedia.com: https://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/crop-rotation-0

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Encyclopedia.com gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia.com cannot guarantee each citation it generates. Therefore, it’s best to use Encyclopedia.com citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:

Modern Language Association

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Notes:
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  • In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.